Docs: keep the progress table in one piece

Progress log entry for the wild-case rendering fixes; "Bevel and 3-D
rotation" moves from missing to partial (approximate bevels, cameras and
face lighting; no extrusion, rigs or 3-D pane); gap estimate narrowed.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

Cargo.lock

@@ -1109,6 +1109,7 @@ dependencies = [
 name = "deckcraft-render"
 version = "0.6.1"
 dependencies = [
+ "deckcraft-anim",
  "deckcraft-color",
  "deckcraft-fonts",
  "deckcraft-geom",

ROADMAP.md

@@ -128,11 +128,15 @@ app's JSON control channel (`deckcraft --control PORT`).
 
 | Date | What landed |
 |---|---|
+| 2026-10-13 | Slide transitions like PowerPoint: every transition and option measured frame by frame against PowerPoint's video export and retuned (curves, directions, soft edges, 3-D perspective, contents moving over backgrounds); PowerPoint's own XML elements and defaults read and written (diagonal Wipe, Zoom, Shape In/Out, Glitter Hexagons, Shred In/Out, Page Curl Single); `deckcraft-cli render-transition` renders frames headless |
+| 2026-10-13 | Wild text cases measured against PowerPoint (102 synthetic slides): bidi by run language, East Asian vertical text upright, mongolianVert/wordArtVert/wordArtVertRtl, underline styles and strikethrough at the font's metrics, centre/right/decimal tabs, East Asian, Thai, Hindi, Arabic and Hebrew numbering, small caps, all-caps "ß", transparent text, soft hyphens, kinsoku, rtlCol and just/dist anchoring, emoji presentation, fallback faces that no longer move the baseline |
+| 2026-10-13 | Render matches PowerPoint more closely on wild shape, picture and table cases: even-odd custom paths, dashes and caps, arrowheads, radial and path gradients, tile rects, rotWithShape, gradient lines, shadows cast by what is drawn (group and perspective too), group fill, picture borders, tiles, reflection, recolour (biLevel, alphaInv, brightness/contrast), table borders and grid default, 20+ preset shapes by their ECMA formulas, default miter joins, and approximate 3-D bevels, cameras and face lighting |
 | 2026-10-12 | Objects off the slide show and can be selected and moved around it in Normal view, as in PowerPoint; the show, exports and thumbnails still clip to the slide (#270) |
 | 2026-10-12 | Korean, Japanese and Chinese input: IME composition shown in place and underlined, one undo step per composition, candidate window at the caret (slide text, notes, fields); interface text (title, notes, outline, sections, comments) borrows installed fonts for scripts the interface fonts lack (#101) |
 | 2026-10-12 | Selection Pane like PowerPoint (#133): front-most first, groups fold, drag and drop restacks among siblings, Bring Forward / Send Backward, Show All / Hide All, eye, rename in place, keyboard; Lock (pane padlock, canvas menu) keeps objects from moving, sizing or rotating and round-trips PowerPoint's locking attributes |
 | 2026-10-12 | Text keys like PowerPoint for Windows (#268): Ctrl+arrows and Ctrl+Shift+arrows by word (punctuation, CJK, emoji, RTL), Ctrl+Backspace/Delete with smart spacing, Ctrl+Up/Down by paragraph, Ctrl+Home/End, End on wrapped lines, Ctrl+]/[ and Ctrl+Shift+>/< font size, Shift+F3 case cycle, word and paragraph selection |
 | 2026-10-12 | EMF/WMF pictures draw their text (fonts, alignment, dx advances, escapement, symbol fonts), pattern and hatch brushes, PATBLT and the XOR/AND see-through shadow; legacy OLE objects show their VML preview and ActiveX controls their pictures |
+| 2026-10-12 | File tab (Backstage) like PowerPoint's (#76): File or Alt+F opens Home, New, Open, Info, Save, Save As, Print, Export, Close, Account and Options over the window, Esc or Back returns, arrows walk the side menu; the start screen is File › Home. Pages run the existing file commands; new `file.info`, print slide ranges (`"1-3, 5"`), Print through a PDF, Ctrl+P, and Close/Ctrl+W ask about unsaved changes |
 | 2026-10-12 | WordArt text warps (`prstTxWarp`): all 40 presets drawn, curves fitted to PowerPoint by observation; warp adjusts round-trip |
 | 2026-10-12 | Render: line widths, dashes and arrowheads inside a group no longer scale with the group's child-coordinate mapping, so a group in a small legacy child space (scale about 1600) draws thin lines instead of covering the slide (#233) |
 | 2026-10-10 | Progress docs restructured to the craftrules standard; full re-measure (breadth 79%, ready ~55%, mainstream ~53%, essentials ~62%, alpha). Landed: Animation Painter (#54), Morph geometry outlines (#27), animated GIF playback (#39), hyperlink colour and following links in the show (#37, #45), date fields in their own format (#36), flipped shapes keep readable text (#35), show transition fix (#46), start screen from the Home button (#49), MCP export lists PDF (#65), OmaStore manifest (#57) |
@@ -146,6 +150,8 @@ app's JSON control channel (`deckcraft --control PORT`).
 
 | Date | Change | Summary |
 |---|---|---|
+| 2026-10-13 | trivial | Progress log: wild text cases |
+| 2026-10-12 | trivial | Progress log: File tab (Backstage, #76) |
 | 2026-10-12 | trivial | Progress log: lines in scaled groups (#233) |
 | 2026-10-10 | minor | Readiness-by-audience table with hours to ~95% for full, mainstream and essentials |
 | 2026-10-10 | minor | Added mainstream practitioner (~53%) and essentials user (~62%); features recomputed from written area weights, ready ~56% → ~55% |

apps/deckcraft-cli/src/main.rs

@@ -3,6 +3,7 @@
 //! ```text
 //! deckcraft-cli info FILE                       # slides, titles, layouts (JSON)
 //! deckcraft-cli render (FILE | --sample) [--slide N | --all] [--scale S] OUT.png|OUT_DIR
+//! deckcraft-cli render-transition FILE --slide N --t T[,T…] [--width PX] OUT.png   # transition frame(s)
 //! deckcraft-cli convert IN OUT                  # .deckcraft ⇄ .pptx, outline .txt, .png (first slide)
 //! deckcraft-cli run [--in FILE | --sample] [--cmd ID[=JSON]]... [--save OUT] [--export OUT] [--print]
 //! deckcraft-cli commands [FILTER]               # list commands (JSON)
@@ -34,6 +35,7 @@ macro_rules! outln {
 
 const USAGE: &str = "usage: deckcraft-cli info FILE
        deckcraft-cli render (FILE | --sample) [--slide N | --all] [--scale S] [--edit] OUT
+       deckcraft-cli render-transition FILE --slide N --t T[,T...] [--width PX] OUT.png
        deckcraft-cli convert IN OUT
        deckcraft-cli run [--in FILE | --sample] [--cmd ID[=JSON]]... [--save OUT] [--export OUT] [--print]
        deckcraft-cli commands [FILTER]
@@ -52,6 +54,7 @@ fn main() -> ExitCode {
         }
         Some("info") => report(info(rest)),
         Some("render") => report(render(rest)),
+        Some("render-transition") => report(render_transition(rest)),
         Some("convert") => report(convert(rest)),
         Some("run") => report(run(rest)),
         Some("commands") => {
@@ -161,6 +164,80 @@ fn render(args: &[String]) -> Result<(), String> {
     Ok(())
 }
 
+/// Frames of slide N's transition (0-based N; from slide N-1, or black for the first slide) at
+/// the given progress values. With several values, OUT gets `-t<value>` before its extension.
+fn render_transition(args: &[String]) -> Result<(), String> {
+    use deckcraft_engine::render;
+    let mut input = None;
+    let mut slide: Option<usize> = None;
+    let mut ts: Vec<f64> = Vec::new();
+    let mut width: Option<f64> = None;
+    let mut out = None;
+    let mut it = args.iter();
+    while let Some(a) = it.next() {
+        match a.as_str() {
+            "--slide" => slide = Some(it.next().and_then(|v| v.parse().ok()).ok_or("--slide needs a number")?),
+            "--t" => {
+                let v = it.next().ok_or("--t needs a value")?;
+                for x in v.split(',') {
+                    let t: f64 = x.trim().parse().map_err(|_| format!("bad --t value `{x}`"))?;
+                    if !t.is_finite() {
+                        return Err(format!("bad --t value `{x}`"));
+                    }
+                    ts.push(t);
+                }
+            }
+            "--width" => {
+                width = Some(it.next().and_then(|v| v.parse().ok()).filter(|w: &f64| w.is_finite() && *w >= 1.0).ok_or("--width needs pixels")?)
+            }
+            other if input.is_none() => input = Some(other.to_string()),
+            other => out = Some(other.to_string()),
+        }
+    }
+    let input = input.ok_or("render-transition needs a FILE")?;
+    let out = out.ok_or("render-transition needs an output path")?;
+    let i = slide.ok_or("render-transition needs --slide N")?;
+    if ts.is_empty() {
+        return Err("render-transition needs --t".into());
+    }
+    let mut s = Session::new();
+    open(&mut s, Some(&input), false)?;
+    let st = s.doc().map_err(|e| e.to_string())?;
+    let doc = &st.doc;
+    let n = doc.slides.len();
+    let Some(sl) = doc.slides.get(i) else { return Err(format!("no slide {i} (the deck has {n})")) };
+    let sw = doc.slide_size.width.max(1.0);
+    let w = width.unwrap_or(sw * 2.0).min(render::MAX_SIDE as f64);
+    let opts = render::RenderOpts { scale: w / sw, ..Default::default() };
+    let tr = sl.transition.clone().unwrap_or_default();
+    // Render both slides once and composite every frame from them (morph re-renders per frame).
+    let prev = i.checked_sub(1);
+    let cached = (tr.kind != "morph").then(|| {
+        let parts = render::uses_slide_parts(&tr.kind, &tr.option).then(|| render::SlideParts::render(doc, prev, i, &opts));
+        (prev.map(|p| render::render_slide(doc, p, &opts)), render::render_slide(doc, i, &opts), parts)
+    });
+    let aspect = sw / doc.slide_size.height.max(1.0);
+    for t in &ts {
+        let img = match &cached {
+            Some((old, new, parts)) => {
+                render::composite_transition(old.as_ref(), new, parts.as_ref(), &render::transition_frame(&tr.kind, &tr.option, *t, aspect))
+            }
+            None => render::render_transition(doc, i, *t, &opts),
+        };
+        let path = if ts.len() == 1 {
+            out.clone()
+        } else {
+            let p = std::path::Path::new(&out);
+            let stem = p.file_stem().and_then(|x| x.to_str()).unwrap_or("frame");
+            let name = format!("{stem}-t{t:.3}.png");
+            p.with_file_name(name).to_string_lossy().into_owned()
+        };
+        std::fs::write(&path, img.to_png()).map_err(|e| format!("{path}: {e}"))?;
+        outln!("{path} ({}×{}) {} {} t={t}", img.width, img.height, tr.kind, tr.option);
+    }
+    Ok(())
+}
+
 fn convert(args: &[String]) -> Result<(), String> {
     let (Some(input), Some(out)) = (args.first(), args.get(1)) else { return Err("convert needs IN and OUT".into()) };
     let mut s = Session::new();

crates/anim/src/lib.rs

@@ -14,24 +14,30 @@
 
 mod easing;
 mod effects;
+mod mesh;
 mod morph;
 mod path;
 mod show;
 mod timeline;
 mod transition;
+mod transition_fx;
+mod transition_geom;
 
 #[cfg(test)]
 mod tests;
+#[cfg(test)]
+mod transition_tests;
 
 pub use deckcraft_model::Rgba;
 use serde::{Deserialize, Serialize};
 
 pub use easing::ease;
+pub use mesh::{MeshVertex, layer_mesh};
 pub use morph::{MorphFrame, MorphPath, MorphText, morph_frame, morph_pairs, morph_xfrm};
 pub use path::{MotionPath, default_path};
 pub use show::{LinkJump, ShowAction, ShowState, safe_url, show_order};
 pub use timeline::{EffectTiming, Sequence, Timeline, TriggerPlay};
-pub use transition::{Layer, Source, transition_layers};
+pub use transition::{DEFAULT_ASPECT, Layer, Source, transition_frame, transition_layers, uses_slide_parts};
 
 /// Animation state of one shape (or one paragraph of a shape's text) at one moment of the show.
 ///

crates/anim/src/mesh.rs

@@ -0,0 +1,139 @@
+//! Triangle meshes for transition layers.
+//!
+//! A [`Layer`] is a textured quad. Drawn as two triangles, a trapezoid (a slide seen in
+//! perspective) bends its texture along the diagonal, because GPUs and simple rasterisers
+//! interpolate texture coordinates linearly in screen space. [`layer_mesh`] splits such quads into a
+//! grid whose vertices follow the projective map from the source rectangle to the quad, so the
+//! picture looks like a flat card turned in 3-D. Rectangles and parallelograms stay two triangles,
+//! wedges one: the per-frame cost stays a handful of vertices per layer.
+
+use crate::transition::Layer;
+
+/// One mesh vertex: position in slide-unit space (0..1, y down), texture coordinate (0..1) and
+/// opacity (the layer's alpha times its corner fade, interpolated).
+#[derive(Clone, Copy, Debug, PartialEq)]
+pub struct MeshVertex {
+    pub pos: [f64; 2],
+    pub uv: [f64; 2],
+    pub a: f64,
+}
+
+/// Grid cells per side for quads that need a projective subdivision.
+const GRID: usize = 8;
+
+/// The triangles of a layer: vertices and index triples into them.
+pub fn layer_mesh(l: &Layer) -> (Vec<MeshVertex>, Vec<[u32; 3]>) {
+    let q = l.quad;
+    let uv = l.uv;
+    let fa = l.fade.map(|f| f * l.alpha);
+    // A wedge (triangle): the 4th corner repeats the 3rd.
+    if q[3] == q[2] && uv[3] == uv[2] {
+        let v = (0..3).map(|k| MeshVertex { pos: q[k], uv: uv[k], a: fa[k] }).collect();
+        return (v, vec![[0, 1, 2]]);
+    }
+    let affine = {
+        // Parallelogram: opposite edges equal.
+        let e1 = [q[1][0] - q[0][0], q[1][1] - q[0][1]];
+        let e2 = [q[2][0] - q[3][0], q[2][1] - q[3][1]];
+        (e1[0] - e2[0]).abs() < 1e-9 && (e1[1] - e2[1]).abs() < 1e-9
+    };
+    let h = if affine { None } else { square_to_quad(q) };
+    let Some(h) = h else {
+        let v = (0..4).map(|k| MeshVertex { pos: q[k], uv: uv[k], a: fa[k] }).collect();
+        return (v, vec![[0, 1, 2], [0, 2, 3]]);
+    };
+    // Small quads (tiles, shards) bend their texture too little to matter: fewer cells.
+    let span = q.iter().flat_map(|p| q.iter().map(move |r| (p[0] - r[0]).abs().max((p[1] - r[1]).abs()))).fold(0.0, f64::max);
+    let n = ((span * 2.0 * GRID as f64).ceil() as usize).clamp(1, GRID);
+    let mut v = Vec::with_capacity((n + 1) * (n + 1));
+    for j in 0..=n {
+        let b = j as f64 / n as f64;
+        for i in 0..=n {
+            let a = i as f64 / n as f64;
+            // Texture: bilinear in (a, b) over the four uv corners (exact for rectangles).
+            let top = lerp2(uv[0], uv[1], a);
+            let bot = lerp2(uv[3], uv[2], a);
+            let t = lerp2(top, bot, b);
+            let at = fa[0] + (fa[1] - fa[0]) * a;
+            let ab = fa[3] + (fa[2] - fa[3]) * a;
+            v.push(MeshVertex { pos: apply(&h, a, b), uv: t, a: at + (ab - at) * b });
+        }
+    }
+    let mut tris = Vec::with_capacity(n * n * 2);
+    let w = (n + 1) as u32;
+    for j in 0..n as u32 {
+        for i in 0..n as u32 {
+            let p = j * w + i;
+            tris.push([p, p + 1, p + w + 1]);
+            tris.push([p, p + w + 1, p + w]);
+        }
+    }
+    (v, tris)
+}
+
+fn lerp2(a: [f64; 2], b: [f64; 2], t: f64) -> [f64; 2] {
+    [a[0] + (b[0] - a[0]) * t, a[1] + (b[1] - a[1]) * t]
+}
+
+/// Projective map taking the unit square's corners (0,0), (1,0), (1,1), (0,1) to `q`'s tl, tr, br,
+/// bl (Heckbert's square-to-quad). `None` when the quad is degenerate.
+fn square_to_quad(q: [[f64; 2]; 4]) -> Option<[f64; 8]> {
+    let [[x0, y0], [x1, y1], [x2, y2], [x3, y3]] = q;
+    let sx = x0 - x1 + x2 - x3;
+    let sy = y0 - y1 + y2 - y3;
+    let (dx1, dx2, dy1, dy2) = (x1 - x2, x3 - x2, y1 - y2, y3 - y2);
+    let den = dx1 * dy2 - dx2 * dy1;
+    if !den.is_finite() || den.abs() < 1e-12 {
+        return None;
+    }
+    let g = (sx * dy2 - dx2 * sy) / den;
+    let h = (dx1 * sy - sx * dy1) / den;
+    let m = [x1 - x0 + g * x1, x3 - x0 + h * x3, x0, y1 - y0 + g * y1, y3 - y0 + h * y3, y0, g, h];
+    m.iter().all(|v| v.is_finite()).then_some(m)
+}
+
+fn apply(m: &[f64; 8], u: f64, v: f64) -> [f64; 2] {
+    let w = m[6] * u + m[7] * v + 1.0;
+    let w = if w.abs() < 1e-9 { 1e-9_f64.copysign(w) } else { w };
+    [(m[0] * u + m[1] * v + m[2]) / w, (m[3] * u + m[4] * v + m[5]) / w]
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::transition::{Layer, Source};
+
+    #[test]
+    fn rect_is_two_triangles() {
+        let (v, t) = layer_mesh(&Layer::full(Source::New, 1.0));
+        assert_eq!((v.len(), t.len()), (4, 2));
+    }
+
+    #[test]
+    fn trapezoid_is_subdivided_projectively() {
+        // A card turned about its left edge: the right edge is shorter.
+        let q = [[0.0, 0.0], [0.6, 0.2], [0.6, 0.8], [0.0, 1.0]];
+        let l = Layer::quad(Source::Old, [0.0, 0.0, 1.0, 1.0], q, 1.0);
+        let (v, t) = layer_mesh(&l);
+        assert_eq!(v.len(), (GRID + 1) * (GRID + 1));
+        assert_eq!(t.len(), GRID * GRID * 2);
+        // A small tile in perspective needs no more than a couple of triangles.
+        let small = Layer::quad(Source::Old, [0.0, 0.0, 1.0, 1.0], [[0.5, 0.5], [0.52, 0.505], [0.52, 0.515], [0.5, 0.52]], 1.0);
+        assert!(layer_mesh(&small).1.len() <= 2);
+        // Corners land on the quad's corners.
+        assert_eq!(v[0].pos, q[0]);
+        let last = v[v.len() - 1].pos;
+        assert!((last[0] - 0.6).abs() < 1e-9 && (last[1] - 0.8).abs() < 1e-9);
+        // The texture's middle column sits nearer the far (short) edge than halfway: foreshortening.
+        let mid = v[GRID / 2].pos[0];
+        assert!(mid > 0.3, "{mid}");
+    }
+
+    #[test]
+    fn degenerate_quads_do_not_blow_up() {
+        let q = [[0.5, 0.5]; 4];
+        let l = Layer::quad(Source::Old, [0.0, 0.0, 1.0, 1.0], q, 1.0);
+        let (v, _) = layer_mesh(&l);
+        assert!(v.iter().all(|p| p.pos[0].is_finite() && p.pos[1].is_finite()));
+    }
+}

crates/anim/src/transition.rs

@@ -1,15 +1,18 @@
 //! Slide transitions as layers of textured quads.
 //!
 //! A frame is drawn over black: each [`Layer`] maps part of a source image (old slide, new slide,
-//! or a solid colour) onto a quad in slide-unit space (0..1, y down). Fake 3-D comes from
-//! trapezoids; wedges are triangles (4th corner repeats the 3rd).
-
-use std::f64::consts::PI;
+//! their backgrounds or contents alone, or a solid colour) onto a quad in slide-unit space (0..1, y
+//! down), with an opacity per corner. Perspective comes from projecting 3-D cards
+//! ([`crate::layer_mesh`] keeps their textures straight); soft edges come from per-corner opacity
+//! ramps; wedges are triangles (4th corner repeats the 3rd).
+//!
+//! The motions, curves, directions and option meanings were measured frame by frame on
+//! PowerPoint's video export of synthetic decks (`plan/powerpoint/tools/synth_transitions.ps1`).
+//! The effects themselves live in [`crate::transition_fx`].
 
 use serde::{Deserialize, Serialize};
 
 use crate::clampf;
-use crate::easing::smooth;
 
 /// What a layer shows.
 #[derive(Clone, Copy, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
@@ -20,6 +23,35 @@ pub enum Source {
     New,
     Black,
     White,
+    /// The outgoing slide's background (background fill plus master and layout graphics) alone.
+    OldBack,
+    /// The incoming slide's background alone.
+    NewBack,
+    /// The outgoing slide's own shapes alone, over transparency.
+    OldContent,
+    /// The incoming slide's own shapes alone, over transparency.
+    NewContent,
+}
+
+impl Source {
+    /// The whole-slide source to draw instead when the parts aren't available: a background
+    /// becomes its slide, content becomes nothing.
+    pub fn whole(self) -> Option<Source> {
+        match self {
+            Source::OldBack => Some(Source::Old),
+            Source::NewBack => Some(Source::New),
+            Source::OldContent | Source::NewContent => None,
+            s => Some(s),
+        }
+    }
+    /// Does this source need the slide rendered in parts (background / content)?
+    pub fn is_part(self) -> bool {
+        matches!(self, Source::OldBack | Source::NewBack | Source::OldContent | Source::NewContent)
+    }
+}
+
+fn ones() -> [f64; 4] {
+    [1.0; 4]
 }
 
 /// One textured quad of a transition frame.
@@ -34,12 +66,18 @@ pub struct Layer {
     /// are the corners of `src`; triangles and mirrored flaps carry their own. Draw with these.
     pub uv: [[f64; 2]; 4],
     pub alpha: f64,
+    /// Opacity of each corner (tl, tr, br, bl), multiplied by `alpha` and interpolated across the
+    /// quad: soft edges and feathered masks.
+    #[serde(default = "ones")]
+    pub fade: [f64; 4],
 }
 
-type R = [f64; 4];
-const FULL: R = [0.0, 0.0, 1.0, 1.0];
+pub(crate) type R = [f64; 4];
+pub(crate) type P = [f64; 2];
+pub(crate) type Q = [[f64; 2]; 4];
+pub(crate) const FULL: R = [0.0, 0.0, 1.0, 1.0];
 
-fn corners(r: R) -> [[f64; 2]; 4] {
+pub(crate) fn corners(r: R) -> Q {
     [[r[0], r[1]], [r[2], r[1]], [r[2], r[3]], [r[0], r[3]]]
 }
 
@@ -50,23 +88,39 @@ impl Layer {
     }
     /// `src` rectangle of the source drawn into the `dst` rectangle.
     pub fn rect(source: Source, src: R, dst: R, alpha: f64) -> Layer {
-        Layer { source, src, quad: corners(dst), uv: corners(src), alpha }
+        Layer { source, src, quad: corners(dst), uv: corners(src), alpha, fade: ones() }
     }
     /// `src` rectangle of the source drawn onto a quad.
-    pub fn quad(source: Source, src: R, quad: [[f64; 2]; 4], alpha: f64) -> Layer {
-        Layer { source, src, quad, uv: corners(src), alpha }
+    pub fn quad(source: Source, src: R, quad: Q, alpha: f64) -> Layer {
+        Layer { source, src, quad, uv: corners(src), alpha, fade: ones() }
     }
     /// The part of the source under `dst` drawn in place.
-    fn inplace(source: Source, dst: R, alpha: f64) -> Layer {
+    pub(crate) fn inplace(source: Source, dst: R, alpha: f64) -> Layer {
         Layer::rect(source, dst, dst, alpha)
     }
-    /// A triangle of the source drawn in place.
-    fn tri(source: Source, a: [f64; 2], b: [f64; 2], c: [f64; 2], alpha: f64) -> Layer {
-        let xs = [a[0], b[0], c[0]];
-        let ys = [a[1], b[1], c[1]];
+    /// A triangle with its own texture coordinates and corner opacities.
+    pub(crate) fn tri_uv(source: Source, p: [P; 3], uv: [P; 3], fade: [f64; 3], alpha: f64) -> Layer {
+        let xs = [uv[0][0], uv[1][0], uv[2][0]];
+        let ys = [uv[0][1], uv[1][1], uv[2][1]];
         let mn = |v: [f64; 3]| v.iter().copied().fold(f64::INFINITY, f64::min);
         let mx = |v: [f64; 3]| v.iter().copied().fold(f64::NEG_INFINITY, f64::max);
-        Layer { source, src: [mn(xs), mn(ys), mx(xs), mx(ys)], quad: [a, b, c, c], uv: [a, b, c, c], alpha }
+        Layer {
+            source,
+            src: [mn(xs), mn(ys), mx(xs), mx(ys)],
+            quad: [p[0], p[1], p[2], p[2]],
+            uv: [uv[0], uv[1], uv[2], uv[2]],
+            alpha,
+            fade: [fade[0], fade[1], fade[2], fade[2]],
+        }
+    }
+    /// With corner opacities.
+    pub(crate) fn faded(mut self, fade: [f64; 4]) -> Layer {
+        self.fade = fade;
+        self
+    }
+    /// A black copy of this layer's shape at `k` of its opacity: shading a card.
+    pub(crate) fn shade(&self, k: f64) -> Layer {
+        Layer { source: Source::Black, alpha: self.alpha * k.clamp(0.0, 1.0), ..*self }
     }
     fn sanitized(mut self) -> Layer {
         let f = |v: f64| if v.is_finite() { v.clamp(-1.0e6, 1.0e6) } else { 0.0 };
@@ -81,827 +135,48 @@ impl Layer {
             c[0] = c[0].clamp(0.0, 1.0);
             c[1] = c[1].clamp(0.0, 1.0);
         }
+        for a in self.fade.iter_mut() {
+            *a = clampf(*a, 0.0, 1.0, 0.0);
+        }
         self.alpha = clampf(self.alpha, 0.0, 1.0, 0.0);
         self
     }
 }
 
-// ---------- geometry helpers ----------
-
-fn offset(r: R, dx: f64, dy: f64) -> R {
-    [r[0] + dx, r[1] + dy, r[2] + dx, r[3] + dy]
-}
-
-fn moved(source: Source, dx: f64, dy: f64, alpha: f64) -> Layer {
-    Layer::rect(source, FULL, offset(FULL, dx, dy), alpha)
-}
-
-/// The whole source scaled about (cx, cy) and moved.
-fn scaled(source: Source, s: f64, cx: f64, cy: f64, dx: f64, dy: f64, alpha: f64) -> Layer {
-    let r = [cx + (0.0 - cx) * s + dx, cy + (0.0 - cy) * s + dy, cx + (1.0 - cx) * s + dx, cy + (1.0 - cy) * s + dy];
-    Layer::rect(source, FULL, r, alpha)
-}
-
-/// Rotate a point about a pivot (degrees).
-fn rot(p: [f64; 2], c: [f64; 2], deg: f64) -> [f64; 2] {
-    let (s, co) = deg.to_radians().sin_cos();
-    let (x, y) = (p[0] - c[0], p[1] - c[1]);
-    [c[0] + x * co - y * s, c[1] + x * s + y * co]
-}
-
-fn rot_quad(q: [[f64; 2]; 4], c: [f64; 2], deg: f64) -> [[f64; 2]; 4] {
-    [rot(q[0], c, deg), rot(q[1], c, deg), rot(q[2], c, deg), rot(q[3], c, deg)]
-}
-
-/// Horizontal perspective: left/right edges shortened by `li`/`ri` (fraction of height, each end).
-fn persp_h(r: R, li: f64, ri: f64) -> [[f64; 2]; 4] {
-    let h = r[3] - r[1];
-    [[r[0], r[1] + li * h], [r[2], r[1] + ri * h], [r[2], r[3] - ri * h], [r[0], r[3] - li * h]]
-}
-
-/// Vertical perspective: top/bottom edges shortened by `ti`/`bi` (fraction of width, each end).
-fn persp_v(r: R, ti: f64, bi: f64) -> [[f64; 2]; 4] {
-    let w = r[2] - r[0];
-    [[r[0] + ti * w, r[1]], [r[2] - ti * w, r[1]], [r[2] - bi * w, r[3]], [r[0] + bi * w, r[3]]]
-}
-
-/// Mirror a rectangle horizontally and/or vertically, or swap its axes (canonical → direction).
-fn map_rect(r: R, mx: bool, my: bool, swap: bool) -> R {
-    let mut r = if swap { [r[1], r[0], r[3], r[2]] } else { r };
-    if mx {
-        r = [1.0 - r[2], r[1], 1.0 - r[0], r[3]];
-    }
-    if my {
-        r = [r[0], 1.0 - r[3], r[2], 1.0 - r[1]];
-    }
-    r
-}
-
-/// Motion direction of an option: l, r, u, d and diagonals.
-fn dir(opt: &str, default: (f64, f64)) -> (f64, f64) {
-    let mut d = (0.0, 0.0);
-    if opt.contains('l') {
-        d.0 = -1.0;
-    }
-    if opt.contains('r') {
-        d.0 = 1.0;
-    }
-    if opt.contains('u') {
-        d.1 = -1.0;
-    }
-    if opt.contains('d') {
-        d.1 = 1.0;
-    }
-    if d == (0.0, 0.0) { default } else { d }
-}
-
-fn hash64(mut x: u64) -> u64 {
-    x = x.wrapping_add(0x9E37_79B9_7F4A_7C15);
-    x = (x ^ (x >> 30)).wrapping_mul(0xBF58_476D_1CE4_E5B9);
-    x = (x ^ (x >> 27)).wrapping_mul(0x94D0_49BB_1331_11EB);
-    x ^ (x >> 31)
-}
-
-/// Deterministic pseudo-random value in [0, 1).
-fn rnd(i: u64) -> f64 {
-    (hash64(i) >> 11) as f64 / (1u64 << 53) as f64
-}
-
-fn ramp(t: f64, order: f64, window: f64) -> f64 {
-    let w = window.clamp(0.01, 1.0);
-    ((t - order * (1.0 - w)) / w).clamp(0.0, 1.0)
-}
-
-fn grid(cols: usize, rows: usize) -> Vec<(usize, usize, R)> {
-    let mut v = Vec::with_capacity(cols * rows);
-    for r in 0..rows {
-        for c in 0..cols {
-            let cell = [c as f64 / cols as f64, r as f64 / rows as f64, (c + 1) as f64 / cols as f64, (r + 1) as f64 / rows as f64];
-            v.push((c, r, cell));
-        }
-    }
-    v
-}
-
-fn center(r: R) -> [f64; 2] {
-    [(r[0] + r[2]) / 2.0, (r[1] + r[3]) / 2.0]
-}
-
-fn scale_rect(r: R, s: f64) -> R {
-    let c = center(r);
-    let hw = (r[2] - r[0]) / 2.0 * s;
-    let hh = (r[3] - r[1]) / 2.0 * s;
-    [c[0] - hw, c[1] - hh, c[0] + hw, c[1] + hh]
-}
-
-// ---------- effects ----------
+/// Slide aspect assumed by [`transition_layers`] (16:9).
+pub const DEFAULT_ASPECT: f64 = 16.0 / 9.0;
 
 /// Layers of the transition `kind` (a [`deckcraft_model::anim::TRANSITIONS`] id) with `option` at
-/// progress `t` (0..1). Draw in order over black. At `t >= 1` the result is the new slide alone;
-/// at `t <= 0` (or NaN) the old slide alone. Morph returns a plain crossfade (the UI renders morph
-/// frames with [`crate::morph_frame`]).
+/// progress `t` (0..1) on a 16:9 slide. See [`transition_frame`].
 pub fn transition_layers(kind: &str, option: &str, t: f64) -> Vec<Layer> {
+    transition_frame(kind, option, t, DEFAULT_ASPECT)
+}
+
+/// Layers of the transition `kind` with `option` at linear progress `t` (0..1; the effect applies
+/// its own easing) on a slide `aspect` wide per unit of height. Draw in order over black. At
+/// `t >= 1` the result is the new slide alone; at `t <= 0` (or NaN) the old slide alone. Morph
+/// returns a plain crossfade (the UI renders morph frames with [`crate::morph_frame`]). Layers
+/// with [`Source::is_part`] sources need the slides rendered as background and content
+/// ([`uses_slide_parts`]).
+pub fn transition_frame(kind: &str, option: &str, t: f64, aspect: f64) -> Vec<Layer> {
     let t = clampf(t, 0.0, 1.0, 0.0);
+    let aspect = if aspect.is_finite() && aspect > 0.01 { aspect.min(100.0) } else { DEFAULT_ASPECT };
     let v = if t >= 1.0 {
         vec![Layer::full(Source::New, 1.0)]
     } else if t <= 0.0 {
         vec![Layer::full(Source::Old, 1.0)]
     } else {
-        layers(kind, option, t, 0)
+        crate::transition_fx::layers(kind, option, t, aspect, 0)
     };
-    v.into_iter().map(Layer::sanitized).filter(|l| l.alpha > 0.0).collect()
+    v.into_iter().map(Layer::sanitized).filter(|l| l.alpha > 0.0 && l.fade.iter().any(|a| *a > 0.0)).collect()
 }
 
-fn crossfade(t: f64) -> Vec<Layer> {
-    vec![Layer::full(Source::Old, 1.0), Layer::full(Source::New, t)]
-}
-
-const RANDOM_KINDS: &[&str] = &[
-    "fade",
-    "push",
-    "wipe",
-    "split",
-    "reveal",
-    "randomBar",
-    "shape",
-    "uncover",
-    "cover",
-    "fallOver",
-    "drape",
-    "curtains",
-    "wind",
-    "prestige",
-    "fracture",
-    "crush",
-    "peelOff",
-    "pageCurlDouble",
-    "airplane",
-    "origami",
-    "dissolve",
-    "checker",
-    "blinds",
-    "clock",
-    "ripple",
-    "honeycomb",
-    "glitter",
-    "vortex",
-    "shred",
-    "switch",
-    "flip",
-    "gallery",
-    "cube",
-    "doors",
-    "box",
-    "comb",
-    "zoom",
-    "pan",
-    "ferris",
-    "conveyor",
-    "rotate",
-    "window",
-    "orbit",
-    "flythrough",
-];
-
-fn layers(kind: &str, option: &str, t: f64, depth: u32) -> Vec<Layer> {
-    use Source::{Black, New, Old, White};
-    let o = option;
-    let s = smooth(t);
+/// Does `kind` animate the slides' backgrounds and contents separately (PowerPoint's Dynamic
+/// Content transitions and Reveal)? Then the frame uses [`Source::OldBack`] & co.
+pub fn uses_slide_parts(kind: &str, option: &str) -> bool {
     match kind {
-        "none" => vec![Layer::full(New, 1.0)],
-        "cut" => {
-            if o == "throughBlack" && t < 0.5 {
-                vec![Layer::full(Black, 1.0)]
-            } else {
-                vec![Layer::full(New, 1.0)]
-            }
-        }
-        "fade" if o == "throughBlack" => {
-            if t < 0.5 {
-                vec![Layer::full(Black, 1.0), Layer::full(Old, 1.0 - 2.0 * t)]
-            } else {
-                vec![Layer::full(Black, 1.0), Layer::full(New, 2.0 * t - 1.0)]
-            }
-        }
-        "fade" | "morph" => crossfade(t),
-        "push" | "pan" => {
-            let (dx, dy) = dir(o, (0.0, -1.0));
-            vec![moved(Old, dx * s, dy * s, 1.0), moved(New, dx * (s - 1.0), dy * (s - 1.0), 1.0)]
-        }
-        "uncover" => {
-            let (dx, dy) = dir(o, (-1.0, 0.0));
-            vec![Layer::full(New, 1.0), moved(Old, dx * s, dy * s, 1.0)]
-        }
-        "cover" => {
-            let (dx, dy) = dir(o, (-1.0, 0.0));
-            vec![Layer::full(Old, 1.0), moved(New, dx * (s - 1.0), dy * (s - 1.0), 1.0)]
-        }
-        "wipe" => wipe(o, t),
-        "split" => {
-            let horz = o.starts_with("horz");
-            let mut v = vec![Layer::full(Old, 1.0)];
-            let rects: Vec<R> = if o.ends_with("In") {
-                vec![[0.0, 0.0, s / 2.0, 1.0], [1.0 - s / 2.0, 0.0, 1.0, 1.0]]
-            } else {
-                vec![[0.5 - s / 2.0, 0.0, 0.5 + s / 2.0, 1.0]]
-            };
-            for r in rects {
-                v.push(Layer::inplace(New, map_rect(r, false, false, horz), 1.0));
-            }
-            v
-        }
-        "reveal" => {
-            let dx = if o.ends_with("Right") { 1.0 } else { -1.0 };
-            if o.starts_with("black") {
-                if t < 0.5 {
-                    vec![Layer::full(Black, 1.0), moved(Old, dx * t * 0.4, 0.0, 1.0 - 2.0 * t)]
-                } else {
-                    vec![Layer::full(Black, 1.0), moved(New, -dx * (1.0 - t) * 0.2, 0.0, 2.0 * t - 1.0)]
-                }
-            } else {
-                vec![Layer::full(New, 1.0), moved(Old, dx * s * 0.6, 0.0, 1.0 - t)]
-            }
-        }
-        "randomBar" => {
-            let horz = o == "horz";
-            let n = 48;
-            let mut v = vec![Layer::full(Old, 1.0)];
-            for i in 0..n {
-                if t > rnd(i as u64 + 17) * 0.98 {
-                    let r = [i as f64 / n as f64, 0.0, (i + 1) as f64 / n as f64, 1.0];
-                    v.push(Layer::inplace(New, map_rect(r, false, false, horz), 1.0));
-                }
-            }
-            v
-        }
-        "shape" => {
-            let form = match o {
-                "circle" | "diamond" | "plus" => o,
-                _ => "box",
-            };
-            let inward = o == "in";
-            if inward {
-                let mut v = vec![Layer::full(New, 1.0)];
-                v.extend(shape_form(Old, form, 1.0 - s));
-                v
-            } else {
-                let mut v = vec![Layer::full(Old, 1.0)];
-                v.extend(shape_form(New, form, s));
-                v
-            }
-        }
-        "flash" => {
-            if t < 0.5 {
-                vec![Layer::full(Old, 1.0), Layer::full(White, (2.0 * t).min(1.0))]
-            } else {
-                vec![Layer::full(New, 1.0), Layer::full(White, 2.0 - 2.0 * t)]
-            }
-        }
-        "fallOver" => {
-            let sg = if o == "r" { 1.0 } else { -1.0 };
-            let a = t * t * PI / 2.0;
-            let top = 1.0 - a.cos();
-            let ins = 0.12 * a.sin();
-            let sh = sg * 0.15 * a.sin();
-            let q = [[ins + sh, top], [1.0 - ins + sh, top], [1.0, 1.0], [0.0, 1.0]];
-            vec![Layer::full(New, 1.0), Layer::quad(Old, FULL, q, 1.0 - t.powi(3))]
-        }
-        "drape" => {
-            let k = t * t;
-            let q = [[0.0, 0.0], [1.0 - 0.3 * k, k], [1.0 - 0.3 * k, 1.0 + k], [0.0, 1.0]];
-            let q = if o == "r" { mirror_q(q) } else { q };
-            vec![Layer::full(New, 1.0), Layer::quad(Old, FULL, q, 1.0 - k)]
-        }
-        "curtains" => {
-            let w = 0.5 * (1.0 - s);
-            let lq = [[0.0, 0.0], [w, 0.12 * s], [w, 1.0 - 0.12 * s], [0.0, 1.0]];
-            let rq = [[1.0 - w, 0.12 * s], [1.0, 0.0], [1.0, 1.0], [1.0 - w, 1.0 - 0.12 * s]];
-            vec![
-                scaled(New, 0.9 + 0.1 * s, 0.5, 0.5, 0.0, 0.0, 1.0),
-                Layer::quad(Old, [0.0, 0.0, 0.5, 1.0], lq, 1.0),
-                Layer::quad(Old, [0.5, 0.0, 1.0, 1.0], rq, 1.0),
-            ]
-        }
-        "wind" => {
-            let d = if o == "r" { 1.0 } else { -1.0 };
-            let r = offset(FULL, d * 1.2 * s, -0.1 * s);
-            let q = [[r[0] + d * 0.2 * s, r[1]], [r[2] + d * 0.2 * s, r[1]], [r[2], r[3]], [r[0], r[3]]];
-            vec![moved(New, -d * 0.3 * (1.0 - s), 0.0, smooth((t * 1.5).min(1.0))), Layer::quad(Old, FULL, q, 1.0 - t)]
-        }
-        "prestige" => vec![scaled(Old, 1.0 - 0.3 * s, 0.5, 0.5, 0.0, 0.2 * s, 1.0 - t), scaled(New, 0.7 + 0.3 * s, 0.5, 0.5, 0.0, 0.0, s)],
-        "fracture" => {
-            let mut v = vec![Layer::full(New, 1.0)];
-            for (c, r, cell) in grid(8, 6) {
-                let i = (r * 8 + c) as u64;
-                let q = ramp(t, rnd(i + 101) * 0.5, 0.5);
-                let cc = center(cell);
-                let (dx, dy) = ((cc[0] - 0.5) * 1.5 * q, (cc[1] - 0.5) * 1.5 * q + 0.5 * q * q);
-                let quad = rot_quad(corners(offset(cell, dx, dy)), [cc[0] + dx, cc[1] + dy], (rnd(i + 7) - 0.5) * 180.0 * q);
-                v.push(Layer::quad(Old, cell, quad, 1.0 - q));
-            }
-            v
-        }
-        "crush" => {
-            let mut v = vec![Layer::full(New, 1.0)];
-            for (c, r, cell) in grid(4, 4) {
-                let i = (r * 4 + c) as u64;
-                let cc = center(cell);
-                let k = 1.0 - s;
-                let pos = [0.5 + (cc[0] - 0.5) * k, 0.5 + (cc[1] - 0.5) * k];
-                let half = scale_rect(cell, k * (0.8 + 0.2 * rnd(i + 3)));
-                let half = offset(half, pos[0] - cc[0], pos[1] - cc[1]);
-                let quad = rot_quad(corners(half), pos, (rnd(i + 5) - 0.5) * 60.0 * s);
-                v.push(Layer::quad(Old, cell, quad, 1.0 - t * t));
-            }
-            v
-        }
-        "peelOff" => {
-            let mut v = vec![Layer::full(New, 1.0)];
-            v.extend(peel(Old, [0.0, 0.0, 1.0, 1.0], s, o == "r"));
-            v
-        }
-        "pageCurlDouble" => {
-            let mut v = vec![Layer::full(New, 1.0)];
-            let left_first = o != "r";
-            v.extend(peel(Old, [0.0, 0.0, 0.5, 1.0], s, !left_first));
-            v.extend(peel(Old, [0.5, 0.0, 1.0, 1.0], s, left_first));
-            v
-        }
-        "airplane" => {
-            let d = if o == "r" { 1.0 } else { -1.0 };
-            let k = 1.0 - 0.8 * s;
-            let r = offset(scale_rect(FULL, k), d * 1.2 * s * s, -0.5 * s * s);
-            let q = persp_h(r, if d > 0.0 { 0.3 * s } else { 0.0 }, if d > 0.0 { 0.0 } else { 0.3 * s });
-            vec![Layer::full(New, 1.0), Layer::quad(Old, FULL, q, 1.0 - t * t)]
-        }
-        "origami" => {
-            let d = if o == "r" { 1.0 } else { -1.0 };
-            let mut v = vec![Layer::full(New, 1.0)];
-            if t < 0.5 {
-                let f = t * 2.0;
-                let w = 0.5 * (1.0 - 0.8 * f);
-                v.push(Layer::quad(Old, [0.0, 0.0, 0.5, 1.0], persp_h([0.5 - w, 0.0, 0.5, 1.0], 0.15 * f, 0.0), 1.0));
-                v.push(Layer::quad(Old, [0.5, 0.0, 1.0, 1.0], persp_h([0.5, 0.0, 0.5 + w, 1.0], 0.0, 0.15 * f), 1.0));
-            } else {
-                let f = (t - 0.5) * 2.0;
-                let r = offset(scale_rect([0.4, 0.0, 0.6, 1.0], 1.0 - 0.6 * f), d * f * 0.8, -0.3 * f);
-                v.push(Layer::quad(Old, FULL, persp_v(r, 0.1, 0.0), 1.0 - f));
-            }
-            v
-        }
-        "dissolve" => {
-            let mut v = vec![Layer::full(Old, 1.0)];
-            for (c, r, cell) in grid(32, 18) {
-                if t > rnd((r * 32 + c) as u64 + 991) * 0.98 {
-                    v.push(Layer::inplace(New, cell, 1.0));
-                }
-            }
-            v
-        }
-        "checker" => {
-            let vert = o == "vert";
-            let (n, m) = (10usize, 8usize);
-            let mut v = vec![Layer::full(Old, 1.0)];
-            for (c, r, cell) in grid(n, m) {
-                let across = if vert { c } else { r };
-                let f = (t * 2.0 - (across % 2) as f64 * 0.5).clamp(0.0, 1.0);
-                if f <= 0.0 {
-                    continue;
-                }
-                let rc = if vert {
-                    [cell[0], cell[1], cell[2], cell[1] + (cell[3] - cell[1]) * f]
-                } else {
-                    [cell[0], cell[1], cell[0] + (cell[2] - cell[0]) * f, cell[3]]
-                };
-                v.push(Layer::inplace(New, rc, 1.0));
-            }
-            v
-        }
-        "blinds" => {
-            let horz = o == "horz";
-            let n = 8;
-            let mut v = vec![Layer::full(Old, 1.0)];
-            for i in 0..n {
-                let x0 = i as f64 / n as f64;
-                let r = [x0, 0.0, x0 + s / n as f64, 1.0];
-                v.push(Layer::inplace(New, map_rect(r, false, false, horz), 1.0));
-            }
-            v
-        }
-        "clock" => clock(o, s),
-        "ripple" => {
-            let origin = match o {
-                "lu" => [0.0, 0.0],
-                "ru" => [1.0, 0.0],
-                "ld" => [0.0, 1.0],
-                "rd" => [1.0, 1.0],
-                _ => [0.5, 0.5],
-            };
-            let maxd = if origin == [0.5, 0.5] { 0.71 } else { 1.42 };
-            let mut v = vec![Layer::full(Old, 1.0)];
-            for (_, _, cell) in grid(24, 14) {
-                let cc = center(cell);
-                let d = ((cc[0] - origin[0]).powi(2) + (cc[1] - origin[1]).powi(2)).sqrt() / maxd;
-                let a = ramp(t, d.min(1.0), 0.3);
-                if a > 0.0 {
-                    let sc = 1.0 + 0.15 * (a * PI).sin();
-                    v.push(Layer::rect(New, cell, scale_rect(cell, sc), a));
-                }
-            }
-            v
-        }
-        "honeycomb" => {
-            let (cols, rows) = (12usize, 8usize);
-            let mut v = vec![Layer::full(Old, 1.0)];
-            for c in 0..cols {
-                let odd = c % 2 == 1;
-                let extra = if odd { 1 } else { 0 };
-                for r in 0..rows + extra {
-                    let y0 = (r as f64 - if odd { 0.5 } else { 0.0 }) / rows as f64;
-                    let cell = [c as f64 / cols as f64, y0.max(0.0), (c + 1) as f64 / cols as f64, (y0 + 1.0 / rows as f64).min(1.0)];
-                    let a = ramp(t, rnd((c * 64 + r) as u64 + 4242), 0.35);
-                    if a > 0.0 {
-                        v.push(Layer::rect(New, cell, scale_rect(cell, 0.3 + 0.7 * a), a));
-                    }
-                }
-            }
-            v
-        }
-        "glitter" => {
-            let (dx, dy) = dir(o, (-1.0, 0.0));
-            let mut v = vec![Layer::full(Old, 1.0)];
-            for (c, r, cell) in grid(20, 12) {
-                let cc = center(cell);
-                let grad = if dx < 0.0 {
-                    1.0 - cc[0]
-                } else if dx > 0.0 {
-                    cc[0]
-                } else if dy < 0.0 {
-                    1.0 - cc[1]
-                } else {
-                    cc[1]
-                };
-                let order = 0.6 * grad + 0.4 * rnd((r * 20 + c) as u64 + 77);
-                let a = ramp(t, order, 0.25);
-                if a > 0.0 {
-                    let quad = rot_quad(corners(cell), cc, (1.0 - a) * 90.0);
-                    v.push(Layer::quad(New, cell, quad, a));
-                }
-            }
-            v
-        }
-        "vortex" => {
-            let (dx, dy) = dir(o, (-1.0, 0.0));
-            let mut v = vec![Layer::full(New, 1.0)];
-            for (c, r, cell) in grid(16, 9) {
-                let i = (r * 16 + c) as u64;
-                let cc = center(cell);
-                let grad = 0.5 + 0.5 * ((cc[0] - 0.5) * -dx + (cc[1] - 0.5) * -dy);
-                let q = ramp(t, 0.5 * grad + 0.5 * rnd(i + 31), 0.4);
-                let ang = q * 2.0 * PI + rnd(i) * PI;
-                let rad = q * 1.2;
-                let (ox, oy) = (dx * q * 0.8 + rad * ang.cos() * 0.3, dy * q * 0.8 + rad * ang.sin() * 0.3);
-                let pos = [cc[0] + ox, cc[1] + oy];
-                let quad = rot_quad(corners(offset(scale_rect(cell, 1.0 - 0.5 * q), ox, oy)), pos, q * 360.0);
-                v.push(Layer::quad(Old, cell, quad, 1.0 - q));
-            }
-            v
-        }
-        "shred" => {
-            let mut v = vec![Layer::full(New, 1.0)];
-            if o == "particles" {
-                for (c, r, cell) in grid(24, 14) {
-                    let i = (r * 24 + c) as u64;
-                    let q = ramp(t, rnd(i + 555) * 0.6 + 0.4 * (1.0 - center(cell)[1]), 0.4);
-                    let dy = q * q * 1.2;
-                    let dx = (rnd(i + 9) - 0.5) * 0.3 * q;
-                    v.push(Layer::rect(Old, cell, offset(scale_rect(cell, 1.0 - 0.6 * q), dx, dy), 1.0 - q));
-                }
-            } else {
-                let n = 16;
-                for i in 0..n {
-                    let x0 = i as f64 / n as f64;
-                    let x1 = (i + 1) as f64 / n as f64;
-                    let q = ramp(t, i as f64 / n as f64 * 0.3 + 0.1 * rnd(i as u64), 0.7);
-                    let dy = if i % 2 == 0 { 1.1 * q * q } else { -1.1 * q * q };
-                    v.push(Layer::rect(Old, [x0, 0.0, x1, 1.0], [x0, dy, x1, 1.0 + dy], 1.0));
-                }
-            }
-            v
-        }
-        "switch" => {
-            let d = if o == "r" { 1.0 } else { -1.0 };
-            let k = (t * PI).sin();
-            let old = Layer::quad(
-                Old,
-                FULL,
-                persp_h(
-                    offset(scale_rect(FULL, 1.0 - 0.25 * t), d * 0.45 * k, 0.0),
-                    if d > 0.0 { 0.0 } else { 0.08 * k },
-                    if d > 0.0 { 0.08 * k } else { 0.0 },
-                ),
-                1.0,
-            );
-            let new = Layer::quad(
-                New,
-                FULL,
-                persp_h(
-                    offset(scale_rect(FULL, 0.75 + 0.25 * t), -d * 0.45 * k, 0.0),
-                    if d > 0.0 { 0.08 * k } else { 0.0 },
-                    if d > 0.0 { 0.0 } else { 0.08 * k },
-                ),
-                1.0,
-            );
-            if t < 0.5 { vec![new, old] } else { vec![old, new] }
-        }
-        "flip" => {
-            let a = PI * s;
-            let w = a.cos().abs();
-            let k = 0.1 * a.sin();
-            let r = [0.5 - w / 2.0, 0.0, 0.5 + w / 2.0, 1.0];
-            let right = o != "l";
-            if t < 0.5 {
-                let q = if right { persp_h(r, -k / 2.0, k) } else { persp_h(r, k, -k / 2.0) };
-                vec![Layer::quad(Old, FULL, q, 1.0)]
-            } else {
-                let q = if right { persp_h(r, k, -k / 2.0) } else { persp_h(r, -k / 2.0, k) };
-                vec![Layer::quad(New, FULL, q, 1.0)]
-            }
-        }
-        "gallery" | "conveyor" => {
-            let d = if o == "r" { 1.0 } else { -1.0 };
-            let k = (s * PI).sin();
-            let sc = 1.0 - if kind == "gallery" { 0.25 } else { 0.1 } * k;
-            let gap = if kind == "gallery" { 1.15 } else { 1.05 };
-            let old = offset(scale_rect(FULL, sc), d * s * gap, 0.0);
-            let new = offset(scale_rect(FULL, sc), d * (s - 1.0) * gap, 0.0);
-            let p = 0.08 * k;
-            vec![
-                Layer::quad(Old, FULL, if d > 0.0 { persp_h(old, 0.0, p) } else { persp_h(old, p, 0.0) }, 1.0),
-                Layer::quad(New, FULL, if d > 0.0 { persp_h(new, p, 0.0) } else { persp_h(new, 0.0, p) }, 1.0),
-            ]
-        }
-        "cube" | "box" | "rotate" => {
-            let (dx, dy) = dir(o, (-1.0, 0.0));
-            let vertical = dy != 0.0 && dx == 0.0;
-            let neg = if vertical { dy < 0.0 } else { dx < 0.0 };
-            let k = (s * PI).sin();
-            let (far_old, far_new, shared) = match kind {
-                "cube" => (0.18 * s, 0.18 * (1.0 - s), 0.05 * k),
-                "box" => (0.0, 0.0, 0.18 * k),
-                _ => (0.25 * s, 0.25 * (1.0 - s), 0.0),
-            };
-            // Canonical: moving toward -x; old on the left [0, 1-s], new on the right [1-s, 1].
-            let split = 1.0 - s;
-            let (old_q, new_q) = if kind == "rotate" {
-                if t < 0.5 {
-                    (Some(canon_q([0.0, 0.0, (1.0 - 2.0 * t).max(0.0), 1.0], far_old, 0.0)), None)
-                } else {
-                    (None, Some(canon_q([1.0 - (2.0 * t - 1.0), 0.0, 1.0, 1.0], 0.0, far_new)))
-                }
-            } else {
-                (Some(canon_q([0.0, 0.0, split, 1.0], far_old, shared)), Some(canon_q([split, 0.0, 1.0, 1.0], shared, far_new)))
-            };
-            let fix = |q: [[f64; 2]; 4]| -> [[f64; 2]; 4] {
-                let q = if neg { q } else { mirror_q(q) };
-                if vertical { swap_q(q) } else { q }
-            };
-            let mut v = vec![Layer::full(Black, 1.0)];
-            if let Some(q) = old_q {
-                v.push(Layer::quad(Old, FULL, fix(q), 1.0));
-            }
-            if let Some(q) = new_q {
-                v.push(Layer::quad(New, FULL, fix(q), 1.0));
-            }
-            v
-        }
-        "doors" | "window" => {
-            let horz = o == "horz";
-            let (zoom0, persp) = if kind == "doors" { (0.85, 0.1) } else { (0.6, 0.2) };
-            let w = 0.5 * (1.0 - s);
-            let k = persp * s;
-            let left = [[0.0, 0.0], [w, -k], [w, 1.0 + k], [0.0, 1.0]];
-            let right = [[1.0 - w, -k], [1.0, 0.0], [1.0, 1.0], [1.0 - w, 1.0 + k]];
-            let (l, r) = if horz { (swap_q(left), swap_q(right)) } else { (left, right) };
-            let (sl, sr) = if horz { ([0.0, 0.0, 1.0, 0.5], [0.0, 0.5, 1.0, 1.0]) } else { ([0.0, 0.0, 0.5, 1.0], [0.5, 0.0, 1.0, 1.0]) };
-            vec![scaled(New, zoom0 + (1.0 - zoom0) * s, 0.5, 0.5, 0.0, 0.0, s.max(0.2)), Layer::quad(Old, sl, l, 1.0), Layer::quad(Old, sr, r, 1.0)]
-        }
-        "comb" => {
-            let vert = o == "vert";
-            let n = 8;
-            let mut v = Vec::new();
-            for i in 0..n {
-                let a = i as f64 / n as f64;
-                let b = (i + 1) as f64 / n as f64;
-                let d = if i % 2 == 0 { 1.0 } else { -1.0 };
-                let band = if vert { [a, 0.0, b, 1.0] } else { [0.0, a, 1.0, b] };
-                let (ox, oy) = if vert { (0.0, d * s) } else { (d * s, 0.0) };
-                let (nx, ny) = if vert { (0.0, -d * (1.0 - s)) } else { (-d * (1.0 - s), 0.0) };
-                v.push(Layer::rect(Old, band, offset(band, ox, oy), 1.0));
-                v.push(Layer::rect(New, band, offset(band, nx, ny), 1.0));
-            }
-            v
-        }
-        "zoom" => {
-            if o == "out" {
-                vec![scaled(New, 1.5 - 0.5 * s, 0.5, 0.5, 0.0, 0.0, s), scaled(Old, 1.0 - 0.7 * s, 0.5, 0.5, 0.0, 0.0, 1.0 - t)]
-            } else {
-                vec![scaled(Old, 1.0 + s, 0.5, 0.5, 0.0, 0.0, 1.0 - t), scaled(New, s.max(0.01), 0.5, 0.5, 0.0, 0.0, s)]
-            }
-        }
-        "orbit" => {
-            let (dx, dy) = dir(o, (-1.0, 0.0));
-            let k = (s * PI).sin();
-            let old = scaled(Old, 1.0 - 0.4 * k, 0.5, 0.5, dx * s + dy.abs() * 0.15 * k, dy * s + dx.abs() * 0.15 * k, 1.0 - 0.5 * s);
-            let new = scaled(New, 1.0 - 0.4 * k, 0.5, 0.5, dx * (s - 1.0) - dy.abs() * 0.15 * k, dy * (s - 1.0) - dx.abs() * 0.15 * k, 0.5 + 0.5 * s);
-            if t < 0.5 { vec![new, old] } else { vec![old, new] }
-        }
-        "flythrough" => {
-            let bounce = o.ends_with("Bounce");
-            let ns = |base: f64| if bounce { base + 0.08 * (s * PI).sin() } else { base };
-            if o.starts_with("out") {
-                vec![scaled(Old, 1.0 - 0.5 * s, 0.5, 0.5, 0.0, 0.0, 1.0 - t), scaled(New, ns(1.5 - 0.5 * s), 0.5, 0.5, 0.0, 0.0, s)]
-            } else {
-                vec![scaled(New, ns(0.5 + 0.5 * s), 0.5, 0.5, 0.0, 0.0, s), scaled(Old, 1.0 + 1.5 * s, 0.5, 0.5, 0.0, 0.0, 1.0 - t)]
-            }
-        }
-        "ferris" => {
-            let d = if o == "r" { 1.0 } else { -1.0 };
-            let pivot = [0.5, 2.5];
-            let a = 50.0 * s * d;
-            let oq = rot_quad(corners(FULL), pivot, a);
-            let nq = rot_quad(corners(FULL), pivot, a - 50.0 * d);
-            vec![Layer::quad(Old, FULL, oq, 1.0), Layer::quad(New, FULL, nq, 1.0)]
-        }
-        "random" if depth == 0 => {
-            let h = option.bytes().fold(0x51ED_u64, |h, b| hash64(h ^ b as u64));
-            let k = RANDOM_KINDS.get((h % RANDOM_KINDS.len() as u64) as usize).copied().unwrap_or("fade");
-            let opt = deckcraft_model::anim::TRANSITIONS.iter().find(|x| x.0 == k).and_then(|x| x.4.first().copied()).unwrap_or("");
-            layers(k, opt, t, depth + 1)
-        }
-        _ => crossfade(t),
+        "pan" | "ferris" | "conveyor" | "rotate" | "window" | "orbit" | "flythrough" => true,
+        "reveal" => !option.starts_with("black"),
+        _ => false,
     }
 }
-
-fn mirror_q(q: [[f64; 2]; 4]) -> [[f64; 2]; 4] {
-    // Mirror x and keep the tl, tr, br, bl order (swap left/right corners).
-    let m = |p: [f64; 2]| [1.0 - p[0], p[1]];
-    [m(q[1]), m(q[0]), m(q[3]), m(q[2])]
-}
-
-fn swap_q(q: [[f64; 2]; 4]) -> [[f64; 2]; 4] {
-    // Transpose x/y; corners reordered so tl, tr, br, bl still map to the source's corners.
-    let s = |p: [f64; 2]| [p[1], p[0]];
-    [s(q[0]), s(q[3]), s(q[2]), s(q[1])]
-}
-
-fn canon_q(r: R, left_inset: f64, right_inset: f64) -> [[f64; 2]; 4] {
-    persp_h(r, left_inset, right_inset)
-}
-
-fn wipe(o: &str, t: f64) -> Vec<Layer> {
-    let mut v = vec![Layer::full(Source::Old, 1.0)];
-    let diag = o.len() == 2;
-    if diag {
-        // Diagonal: columns revealed by a slanted edge.
-        let (mx, my) = (o.contains('l'), o.contains('u'));
-        let n = 32;
-        for i in 0..n {
-            let x0 = i as f64 / n as f64;
-            let x1 = (i + 1) as f64 / n as f64;
-            let h = (2.0 * t - (x0 + x1) / 2.0).clamp(0.0, 1.0);
-            if h > 0.0 {
-                v.push(Layer::inplace(Source::New, map_rect([x0, 0.0, x1, h], mx, my, false), 1.0));
-            }
-        }
-        return v;
-    }
-    let (mx, swap) = match o {
-        "l" => (true, false),
-        "d" => (false, true),
-        "u" => (true, true),
-        _ => (false, false),
-    };
-    let soft = 0.15;
-    let e = t * (1.0 + soft);
-    let solid = (e - soft).clamp(0.0, 1.0);
-    if solid > 0.0 {
-        v.push(Layer::inplace(Source::New, map_rect([0.0, 0.0, solid, 1.0], mx, false, swap), 1.0));
-    }
-    let n = 6;
-    for k in 0..n {
-        let a = e - soft + soft * k as f64 / n as f64;
-        let b = e - soft + soft * (k + 1) as f64 / n as f64;
-        let (a, b) = (a.clamp(0.0, 1.0), b.clamp(0.0, 1.0));
-        if b > a {
-            let alpha = 1.0 - (k as f64 + 0.5) / n as f64;
-            v.push(Layer::inplace(Source::New, map_rect([a, 0.0, b, 1.0], mx, false, swap), alpha));
-        }
-    }
-    v
-}
-
-/// A centred shape of the source at size `f` (0 = nothing, 1 = covers the slide), as strips.
-fn shape_form(src: Source, form: &str, f: f64) -> Vec<Layer> {
-    let f = f.clamp(0.0, 1.0);
-    if f <= 0.0 {
-        return vec![];
-    }
-    match form {
-        "plus" => {
-            let h = f / 2.0;
-            vec![Layer::inplace(src, [0.0, 0.5 - h, 1.0, 0.5 + h], 1.0), Layer::inplace(src, [0.5 - h, 0.0, 0.5 + h, 1.0], 1.0)]
-        }
-        "circle" | "diamond" => {
-            let n = 40;
-            let r = if form == "circle" { f * 0.75 } else { f * 1.02 };
-            let mut v = Vec::new();
-            for i in 0..n {
-                let y0 = i as f64 / n as f64;
-                let y1 = (i + 1) as f64 / n as f64;
-                let dy = ((y0 + y1) / 2.0 - 0.5).abs();
-                let half = if form == "circle" { if r > dy { (r * r - dy * dy).sqrt() } else { 0.0 } } else { r - dy };
-                if half > 0.0 {
-                    let half = half.min(0.5);
-                    v.push(Layer::inplace(src, [0.5 - half, y0, 0.5 + half, y1], 1.0));
-                }
-            }
-            v
-        }
-        _ => vec![Layer::inplace(src, scale_rect(FULL, f), 1.0)],
-    }
-}
-
-/// A peeling page: the part of `area` not yet peeled stays, the peeled part shows as a mirrored flap.
-fn peel(src: Source, area: R, s: f64, toward_right: bool) -> Vec<Layer> {
-    let w = area[2] - area[0];
-    let p = s * w;
-    if toward_right {
-        let edge = area[0] + p;
-        let stay = [edge, area[1], area[2], area[3]];
-        let flap_src = [area[0], area[1], edge, area[3]];
-        let x2 = edge + p;
-        let flap = Layer {
-            source: src,
-            src: flap_src,
-            quad: [[x2, area[1]], [edge, area[1]], [edge, area[3]], [x2, area[3]]],
-            uv: corners(flap_src),
-            alpha: 0.85,
-        };
-        vec![Layer::inplace(src, stay, 1.0), flap]
-    } else {
-        let edge = area[2] - p;
-        let stay = [area[0], area[1], edge, area[3]];
-        let flap_src = [edge, area[1], area[2], area[3]];
-        let x2 = edge - p;
-        let flap = Layer {
-            source: src,
-            src: flap_src,
-            quad: [[edge, area[1]], [x2, area[1]], [x2, area[3]], [edge, area[3]]],
-            uv: corners(flap_src),
-            alpha: 0.85,
-        };
-        vec![Layer::inplace(src, stay, 1.0), flap]
-    }
-}
-
-/// Point on the unit square's boundary seen from the centre at angle `a` (radians, clockwise from
-/// 12 o'clock).
-fn boundary(a: f64) -> [f64; 2] {
-    let (dx, dy) = (a.sin(), -a.cos());
-    let m = dx.abs().max(dy.abs()).max(1e-9);
-    [0.5 + 0.5 * dx / m, 0.5 + 0.5 * dy / m]
-}
-
-fn clock(o: &str, s: f64) -> Vec<Layer> {
-    let mut v = vec![Layer::full(Source::Old, 1.0)];
-    let c = [0.5, 0.5];
-    let sweep = s * 2.0 * PI;
-    let (a0, a1) = match o {
-        "counterClockwise" => (-sweep, 0.0),
-        "wedge" => (-sweep / 2.0, sweep / 2.0),
-        _ => (0.0, sweep),
-    };
-    let span = a1 - a0;
-    if span <= 0.0 {
-        return v;
-    }
-    let n = ((span / (PI / 24.0)).ceil() as usize).clamp(1, 96);
-    let mut angles: Vec<f64> = (0..=n).map(|k| a0 + span * k as f64 / n as f64).collect();
-    // Square corners inside the sweep, so the fan reaches them.
-    for k in -8i32..=8 {
-        let a = PI / 4.0 + k as f64 * PI / 2.0;
-        if a > a0 && a < a1 {
-            angles.push(a);
-        }
-    }
-    angles.sort_by(f64::total_cmp);
-    for w in angles.windows(2) {
-        if let [x, y] = w
-            && y > x
-        {
-            v.push(Layer::tri(Source::New, c, boundary(*x), boundary(*y), 1.0));
-        }
-    }
-    v
-}

crates/anim/src/transition_geom.rs

@@ -0,0 +1,382 @@
+//! Geometry for transition effects: easing, 3-D cards, opacity fields, polygons.
+
+use std::f64::consts::PI;
+
+use crate::easing::{ease, smooth};
+use crate::transition::{FULL, Layer, P, Q, R, Source, corners};
+
+// ---------- easing ----------
+
+/// Smoothstep ease in-out (PowerPoint's fades).
+pub(crate) fn ss(x: f64) -> f64 {
+    smooth(x)
+}
+
+/// Quadratic ease in-out: velocity ramps up for the first half and down for the second
+/// (PowerPoint's moves: Push, Cover, Uncover, Pan…).
+pub(crate) fn q2(x: f64) -> f64 {
+    ease(x, 0.5, 0.5, 0.0)
+}
+
+/// Power ease in-out of degree `n` (2: quadratic, 3: cubic, 4: quartic).
+pub(crate) fn pow_inout(x: f64, n: f64) -> f64 {
+    let x = x.clamp(0.0, 1.0);
+    if x < 0.5 { 0.5 * (2.0 * x).powf(n) } else { 1.0 - 0.5 * (2.0 - 2.0 * x).powf(n) }
+}
+
+/// Quadratic ease-in.
+pub(crate) fn ein(x: f64) -> f64 {
+    let x = x.clamp(0.0, 1.0);
+    x * x
+}
+
+/// Quadratic ease-out.
+pub(crate) fn eout(x: f64) -> f64 {
+    let x = 1.0 - x.clamp(0.0, 1.0);
+    1.0 - x * x
+}
+
+/// Progress through the window [a, b] of t, clamped to 0..1.
+pub(crate) fn win(t: f64, a: f64, b: f64) -> f64 {
+    if b <= a {
+        return if t >= b { 1.0 } else { 0.0 };
+    }
+    ((t - a) / (b - a)).clamp(0.0, 1.0)
+}
+
+// ---------- randomness ----------
+
+pub(crate) fn hash64(mut x: u64) -> u64 {
+    x = x.wrapping_add(0x9E37_79B9_7F4A_7C15);
+    x = (x ^ (x >> 30)).wrapping_mul(0xBF58_476D_1CE4_E5B9);
+    x = (x ^ (x >> 27)).wrapping_mul(0x94D0_49BB_1331_11EB);
+    x ^ (x >> 31)
+}
+
+/// Deterministic pseudo-random value in [0, 1).
+pub(crate) fn rnd(i: u64) -> f64 {
+    (hash64(i) >> 11) as f64 / (1u64 << 53) as f64
+}
+
+// ---------- 2-D ----------
+
+pub(crate) fn offset(r: R, dx: f64, dy: f64) -> R {
+    [r[0] + dx, r[1] + dy, r[2] + dx, r[3] + dy]
+}
+
+pub(crate) fn center(r: R) -> P {
+    [(r[0] + r[2]) / 2.0, (r[1] + r[3]) / 2.0]
+}
+
+pub(crate) fn scale_rect(r: R, s: f64) -> R {
+    scale_rect_about(r, s, center(r))
+}
+
+pub(crate) fn scale_rect_about(r: R, s: f64, c: P) -> R {
+    [c[0] + (r[0] - c[0]) * s, c[1] + (r[1] - c[1]) * s, c[0] + (r[2] - c[0]) * s, c[1] + (r[3] - c[1]) * s]
+}
+
+/// The whole source moved by (dx, dy).
+pub(crate) fn moved(source: Source, dx: f64, dy: f64, alpha: f64) -> Layer {
+    Layer::rect(source, FULL, offset(FULL, dx, dy), alpha)
+}
+
+/// The whole source scaled by `s` about (cx, cy) and moved.
+pub(crate) fn scaled(source: Source, s: f64, cx: f64, cy: f64, dx: f64, dy: f64, alpha: f64) -> Layer {
+    Layer::rect(source, FULL, offset(scale_rect_about(FULL, s, [cx, cy]), dx, dy), alpha)
+}
+
+/// Rotate a point about a pivot by `deg` (clockwise on screen), in a slide `a` wide per unit of
+/// height, so angles and shapes stay true.
+pub(crate) fn rot(p: P, c: P, deg: f64, a: f64) -> P {
+    let (s, co) = deg.to_radians().sin_cos();
+    let (x, y) = ((p[0] - c[0]) * a, p[1] - c[1]);
+    [c[0] + (x * co - y * s) / a, c[1] + x * s + y * co]
+}
+
+pub(crate) fn rot_quad(q: Q, c: P, deg: f64, a: f64) -> Q {
+    [rot(q[0], c, deg, a), rot(q[1], c, deg, a), rot(q[2], c, deg, a), rot(q[3], c, deg, a)]
+}
+
+/// Motion direction of an option: l, r, u, d and diagonals.
+pub(crate) fn dir(opt: &str, default: (f64, f64)) -> (f64, f64) {
+    let mut d = (0.0, 0.0);
+    if opt.contains('l') {
+        d.0 = -1.0;
+    }
+    if opt.contains('r') {
+        d.0 = 1.0;
+    }
+    if opt.contains('u') {
+        d.1 = -1.0;
+    }
+    if opt.contains('d') {
+        d.1 = 1.0;
+    }
+    if d == (0.0, 0.0) { default } else { d }
+}
+
+/// A rectangle with a soft border `f` wide (slide units) fading out to nothing: the rectangle at
+/// full opacity, four edge ramps and four corner ramps. `src` maps onto `dst`; the border samples
+/// the texture's edge.
+pub(crate) fn soft_rect(source: Source, src: R, dst: R, f: f64, alpha: f64) -> Vec<Layer> {
+    let mut v = vec![Layer::rect(source, src, dst, alpha)];
+    if f <= 1e-6 {
+        return v;
+    }
+    let (l, t, r, b) = (dst[0], dst[1], dst[2], dst[3]);
+    let (fx, fy) = (f, f * 16.0 / 9.0);
+    let uv_at = |x: f64, y: f64| -> P {
+        let u = if r > l { src[0] + (x.clamp(l, r) - l) / (r - l) * (src[2] - src[0]) } else { src[0] };
+        let w = if b > t { src[1] + (y.clamp(t, b) - t) / (b - t) * (src[3] - src[1]) } else { src[1] };
+        [u, w]
+    };
+    let mut q = |pts: Q, fade: [f64; 4]| {
+        let uv = pts.map(|p| uv_at(p[0], p[1]));
+        let xs = uv.map(|p| p[0]);
+        let ys = uv.map(|p| p[1]);
+        let mn = |a: [f64; 4]| a.iter().copied().fold(f64::INFINITY, f64::min);
+        let mx = |a: [f64; 4]| a.iter().copied().fold(f64::NEG_INFINITY, f64::max);
+        v.push(Layer { source, src: [mn(xs), mn(ys), mx(xs), mx(ys)], quad: pts, uv, alpha, fade });
+    };
+    q([[l, t - fy], [r, t - fy], [r, t], [l, t]], [0.0, 0.0, 1.0, 1.0]);
+    q([[l, b], [r, b], [r, b + fy], [l, b + fy]], [1.0, 1.0, 0.0, 0.0]);
+    q([[l - fx, t], [l, t], [l, b], [l - fx, b]], [0.0, 1.0, 1.0, 0.0]);
+    q([[r, t], [r + fx, t], [r + fx, b], [r, b]], [1.0, 0.0, 0.0, 1.0]);
+    q([[l - fx, t - fy], [l, t - fy], [l, t], [l - fx, t]], [0.0, 0.0, 1.0, 0.0]);
+    q([[r, t - fy], [r + fx, t - fy], [r + fx, t], [r, t]], [0.0, 0.0, 0.0, 1.0]);
+    q([[r, b], [r + fx, b], [r + fx, b + fy], [r, b + fy]], [1.0, 0.0, 0.0, 0.0]);
+    q([[l - fx, b], [l, b], [l, b + fy], [l - fx, b + fy]], [0.0, 1.0, 0.0, 0.0]);
+    v
+}
+
+// ---------- opacity fields ----------
+
+/// The source shown in place through an opacity field `f(x, y)` (0..1) sampled on an `n` × `m`
+/// grid: each cell is a quad with its corners' opacities. Cells with nothing to show are left out
+/// and runs of fully opaque cells merge, so most frames stay small.
+pub(crate) fn field(source: Source, n: usize, m: usize, f: &dyn Fn(f64, f64) -> f64) -> Vec<Layer> {
+    let (n, m) = (n.clamp(1, 256), m.clamp(1, 256));
+    let mut vals = vec![0.0; (n + 1) * (m + 1)];
+    for j in 0..=m {
+        for i in 0..=n {
+            let v = f(i as f64 / n as f64, j as f64 / m as f64);
+            if let Some(x) = vals.get_mut(j * (n + 1) + i) {
+                *x = if v.is_finite() { v.clamp(0.0, 1.0) } else { 0.0 };
+            }
+        }
+    }
+    let at = |i: usize, j: usize| vals.get(j * (n + 1) + i).copied().unwrap_or(0.0);
+    let mut out = Vec::new();
+    for j in 0..m {
+        let (y0, y1) = (j as f64 / m as f64, (j + 1) as f64 / m as f64);
+        let mut run: Option<usize> = None;
+        for i in 0..=n {
+            let full = i < n && at(i, j) >= 1.0 && at(i + 1, j) >= 1.0 && at(i, j + 1) >= 1.0 && at(i + 1, j + 1) >= 1.0;
+            if full {
+                run.get_or_insert(i);
+                continue;
+            }
+            if let Some(s) = run.take() {
+                out.push(Layer::inplace(source, [s as f64 / n as f64, y0, i as f64 / n as f64, y1], 1.0));
+            }
+            if i == n {
+                break;
+            }
+            let c = [at(i, j), at(i + 1, j), at(i + 1, j + 1), at(i, j + 1)];
+            if c.iter().all(|v| *v <= 0.0) {
+                continue;
+            }
+            out.push(Layer::inplace(source, [i as f64 / n as f64, y0, (i + 1) as f64 / n as f64, y1], 1.0).faded(c));
+        }
+    }
+    out
+}
+
+/// Opacity of a soft edge at position `p` when the edge's middle is at `c` and it ramps over `w`.
+pub(crate) fn edge(c: f64, p: f64, w: f64) -> f64 {
+    if w <= 1e-9 {
+        return if p <= c { 1.0 } else { 0.0 };
+    }
+    ((c - p) / w + 0.5).clamp(0.0, 1.0)
+}
+
+/// Point on the unit square's boundary seen from its centre at angle `ang` (radians, clockwise
+/// from 12 o'clock, measured on a slide `a` wide per unit of height).
+pub(crate) fn boundary(ang: f64, a: f64) -> P {
+    let (dx, dy) = (ang.sin() / a, -ang.cos());
+    let m = (dx.abs() / 0.5).max(dy.abs() / 0.5).max(1e-9);
+    [0.5 + dx / m, 0.5 + dy / m]
+}
+
+/// The source shown in place through an angular opacity field `f(angle)` (radians clockwise from
+/// 12 o'clock, 0..2π): a fan of thin wedges from the centre.
+pub(crate) fn fan(source: Source, a: f64, steps: usize, f: &dyn Fn(f64) -> f64) -> Vec<Layer> {
+    let n = steps.clamp(8, 720);
+    let mut angles: Vec<f64> = (0..=n).map(|k| 2.0 * PI * k as f64 / n as f64).collect();
+    // The square's corners, so wedges reach them.
+    for c in [[1.0, 0.0], [1.0, 1.0], [0.0, 1.0], [0.0, 0.0]] {
+        let ang = ((c[0] - 0.5) * a).atan2(-(c[1] - 0.5));
+        angles.push(ang.rem_euclid(2.0 * PI));
+    }
+    angles.sort_by(f64::total_cmp);
+    angles.dedup_by(|x, y| (*x - *y).abs() < 1e-9);
+    let mut out = Vec::new();
+    let c = [0.5, 0.5];
+    for w in angles.windows(2) {
+        let [x, y] = w else { continue };
+        let (fx, fy) = (f(*x).clamp(0.0, 1.0), f(*y).clamp(0.0, 1.0));
+        if fx <= 0.0 && fy <= 0.0 {
+            continue;
+        }
+        let (bx, by) = (boundary(*x, a), boundary(*y, a));
+        out.push(Layer::tri_uv(source, [c, bx, by], [c, bx, by], [(fx + fy) / 2.0, fx, fy], 1.0));
+    }
+    out
+}
+
+// ---------- polygons ----------
+
+/// Keep the part of a convex polygon where `n · p <= d`.
+pub(crate) fn clip(poly: &[P], n: P, d: f64) -> Vec<P> {
+    let mut out = Vec::with_capacity(poly.len() + 2);
+    let side = |p: P| n[0] * p[0] + n[1] * p[1] - d;
+    for (i, p) in poly.iter().enumerate() {
+        let q = poly.get((i + 1) % poly.len()).copied().unwrap_or(*p);
+        let (sp, sq) = (side(*p), side(q));
+        if sp <= 0.0 {
+            out.push(*p);
+        }
+        if (sp < 0.0 && sq > 0.0) || (sp > 0.0 && sq < 0.0) {
+            let k = sp / (sp - sq);
+            out.push([p[0] + (q[0] - p[0]) * k, p[1] + (q[1] - p[1]) * k]);
+        }
+    }
+    out
+}
+
+/// A convex polygon as triangles: vertices drawn at `map(p)` with texture coordinate `p`.
+pub(crate) fn poly_layers(source: Source, poly: &[P], alpha: f64, map: &dyn Fn(P) -> P) -> Vec<Layer> {
+    let Some(first) = poly.first().copied() else { return vec![] };
+    poly.windows(2)
+        .skip(1)
+        .filter_map(|w| match w {
+            [b, c] => Some(Layer::tri_uv(source, [map(first), map(*b), map(*c)], [first, *b, *c], [1.0; 3], alpha)),
+            _ => None,
+        })
+        .collect()
+}
+
+pub(crate) fn rect_poly(r: R) -> Vec<P> {
+    corners(r).to_vec()
+}
+
+// ---------- 3-D ----------
+
+/// A point in the 3-D scene: x right and y down in slide heights (the slide spans x ∈ [−a/2, a/2],
+/// y ∈ [−½, ½] at z = 0), z away from the viewer.
+#[derive(Clone, Copy, Debug, PartialEq)]
+pub(crate) struct V3 {
+    pub x: f64,
+    pub y: f64,
+    pub z: f64,
+}
+
+pub(crate) fn v3(x: f64, y: f64, z: f64) -> V3 {
+    V3 { x, y, z }
+}
+
+impl V3 {
+    pub fn add(self, o: V3) -> V3 {
+        v3(self.x + o.x, self.y + o.y, self.z + o.z)
+    }
+    pub fn sub(self, o: V3) -> V3 {
+        v3(self.x - o.x, self.y - o.y, self.z - o.z)
+    }
+    /// Rotate about the vertical axis through `c` (degrees; positive turns the right side away).
+    pub fn yaw(self, c: V3, deg: f64) -> V3 {
+        let (s, co) = deg.to_radians().sin_cos();
+        let p = self.sub(c);
+        v3(p.x * co - p.z * s, p.y, p.x * s + p.z * co).add(c)
+    }
+    /// Rotate about the horizontal axis through `c` (degrees; positive turns the top away).
+    pub fn pitch(self, c: V3, deg: f64) -> V3 {
+        let (s, co) = deg.to_radians().sin_cos();
+        let p = self.sub(c);
+        v3(p.x, p.y * co + p.z * s, -p.y * s + p.z * co).add(c)
+    }
+    /// Rotate in the screen plane about `c` (degrees, clockwise).
+    pub fn roll(self, c: V3, deg: f64) -> V3 {
+        let (s, co) = deg.to_radians().sin_cos();
+        let p = self.sub(c);
+        v3(p.x * co - p.y * s, p.x * s + p.y * co, p.z).add(c)
+    }
+}
+
+/// A perspective camera looking at the slide plane from `d` slide heights away.
+#[derive(Clone, Copy, Debug)]
+pub(crate) struct Cam {
+    pub a: f64,
+    pub d: f64,
+}
+
+impl Cam {
+    pub fn p(&self, v: V3) -> P {
+        let k = self.d / (self.d + v.z).max(self.d * 0.02);
+        [v.x * k / self.a + 0.5, v.y * k + 0.5]
+    }
+    /// The 3-D corners (tl, tr, br, bl) of the unit-space rectangle `r` lying on the slide plane.
+    pub fn rect(&self, r: R) -> [V3; 4] {
+        corners(r).map(|p| v3((p[0] - 0.5) * self.a, p[1] - 0.5, 0.0))
+    }
+    /// The unit-space point of a 3-D point on the slide plane.
+    pub fn unit(&self, x: f64, y: f64) -> V3 {
+        v3((x - 0.5) * self.a, y - 0.5, 0.0)
+    }
+    pub fn quad(&self, c: [V3; 4]) -> Q {
+        c.map(|v| self.p(v))
+    }
+}
+
+/// Signed area of a quad (positive: front side facing the viewer).
+pub(crate) fn area(q: &Q) -> f64 {
+    let mut s = 0.0;
+    for i in 0..4 {
+        let (a, b) = (q[i], q[(i + 1) % 4]);
+        s += a[0] * b[1] - b[0] * a[1];
+    }
+    s / 2.0
+}
+
+/// A card: `src` of the source mapped onto 3-D corners, if it faces the viewer; `shade` (0..1)
+/// darkens it. Seen from behind it is left out unless `back` is set (then drawn mirrored).
+pub(crate) fn card(cam: &Cam, source: Source, src: R, c: [V3; 4], alpha: f64, shade: f64, back: bool) -> Vec<Layer> {
+    let q = cam.quad(c);
+    if !q.iter().all(|p| p[0].is_finite() && p[1].is_finite()) {
+        return vec![];
+    }
+    let front = area(&q) > 0.0;
+    if !front && !back {
+        return vec![];
+    }
+    let l = Layer::quad(source, src, q, alpha);
+    let mut v = vec![l];
+    if shade > 0.001 {
+        v.push(l.shade(shade));
+    }
+    v
+}
+
+/// How much a card facing along `n` (unit normal toward the viewer is (0, 0, −1)) is darkened by
+/// the light behind the viewer: 0 facing straight on.
+pub(crate) fn facing_shade(c: [V3; 4], k: f64) -> f64 {
+    let u = c[1].sub(c[0]);
+    let w = c[3].sub(c[0]);
+    let n = v3(u.y * w.z - u.z * w.y, u.z * w.x - u.x * w.z, u.x * w.y - u.y * w.x);
+    let len = (n.x * n.x + n.y * n.y + n.z * n.z).sqrt();
+    if len < 1e-12 {
+        return 0.0;
+    }
+    let cos = (n.z / len).abs();
+    (k * (1.0 - cos)).clamp(0.0, 1.0)
+}

crates/anim/src/transition_tests.rs

@@ -0,0 +1,230 @@
+//! Transition curves and geometry against values measured on PowerPoint's video export
+//! (`plan/powerpoint/tools/synth_transitions.ps1`, 2 s transitions, 30 fps).
+
+#![allow(clippy::unwrap_used, clippy::expect_used, clippy::panic)]
+
+use deckcraft_model::anim::TRANSITIONS;
+
+use crate::transition::{Layer, Source, transition_frame, transition_layers, uses_slide_parts};
+use crate::transition_geom::{edge, pow_inout, q2, ss};
+
+const A: f64 = 16.0 / 9.0;
+
+fn near(a: f64, b: f64, tol: f64) -> bool {
+    (a - b).abs() <= tol
+}
+
+fn of(ls: &[Layer], src: Source) -> Vec<&Layer> {
+    ls.iter().filter(|l| l.source == src).collect()
+}
+
+fn left(l: &Layer) -> f64 {
+    l.quad.iter().map(|p| p[0]).fold(f64::INFINITY, f64::min)
+}
+
+fn top(l: &Layer) -> f64 {
+    l.quad.iter().map(|p| p[1]).fold(f64::INFINITY, f64::min)
+}
+
+#[test]
+fn fade_follows_powerpoints_s_curve() {
+    // Measured share of the new slide in a 2 s Fade at t = 0.25, 0.5, 0.75: 0.155, 0.49, 0.82.
+    for (t, want) in [(0.25, 0.155), (0.5, 0.49), (0.75, 0.82)] {
+        let ls = transition_layers("fade", "smoothly", t);
+        let new = of(&ls, Source::New);
+        assert!(near(new[0].alpha, want, 0.04), "t={t}: {}", new[0].alpha);
+    }
+    // Through black: the old slide is gone to black at the middle, then the new one fades in.
+    let mid = transition_layers("fade", "throughBlack", 0.5);
+    assert!(mid.iter().all(|l| l.source == Source::Black));
+    let q = transition_layers("fade", "throughBlack", 0.25);
+    assert!(near(of(&q, Source::Old)[0].alpha, 0.5, 0.01));
+}
+
+#[test]
+fn push_moves_both_slides_with_an_eased_curve() {
+    for (o, dx, dy) in [("l", -1.0, 0.0), ("r", 1.0, 0.0), ("u", 0.0, -1.0), ("d", 0.0, 1.0)] {
+        for t in [0.25, 0.5, 0.75] {
+            let ls = transition_layers("push", o, t);
+            let (old, new) = (of(&ls, Source::Old)[0], of(&ls, Source::New)[0]);
+            let s = q2(t);
+            assert!(near(old.quad[0][0], dx * s, 1e-9) && near(old.quad[0][1], dy * s, 1e-9), "{o} {t}");
+            assert!(near(new.quad[0][0], dx * (s - 1.0), 1e-9) && near(new.quad[0][1], dy * (s - 1.0), 1e-9), "{o} {t}");
+        }
+    }
+    // Ease in-out: slow at both ends.
+    assert!(q2(0.1) < 0.05 && q2(0.9) > 0.95 && near(q2(0.5), 0.5, 1e-9));
+}
+
+#[test]
+fn cover_and_uncover_match_measured_positions() {
+    // Offset of the new slide in Cover Left (fraction of the width) at measured times.
+    for (t, off) in [(0.445, 0.655), (0.495, 0.512), (0.544, 0.359), (0.643, 0.134), (0.742, 0.046)] {
+        let ls = transition_layers("cover", "l", t);
+        assert!(near(left(of(&ls, Source::New)[0]), off, 0.05), "cover t={t}");
+    }
+    // Offset of the old slide in Uncover Left.
+    for (t, off) in [(0.244, -0.06), (0.343, -0.14), (0.442, -0.32), (0.508, -0.5), (0.558, -0.63)] {
+        let ls = transition_layers("uncover", "l", t);
+        assert!(near(left(of(&ls, Source::Old)[0]), off, 0.05), "uncover t={t}");
+    }
+    // Diagonal Cover shoots in and settles slowly.
+    for (t, off) in [(0.142, 0.728), (0.257, 0.49), (0.356, 0.29), (0.455, 0.146), (0.604, 0.053)] {
+        let ls = transition_layers("cover", "lu", t);
+        let n = of(&ls, Source::New)[0];
+        assert!(near(left(n), off, 0.06) && near(top(n), off, 0.06), "cover lu t={t}");
+    }
+    assert!(near(pow_inout(0.25, 3.0), 0.0625, 1e-9));
+}
+
+#[test]
+fn wipe_has_a_wide_soft_edge() {
+    // Measured along a row of Wipe Right at t = 0.5: about half-way through at x = 0.6, nearly
+    // nothing at the right edge, fully new on the left third.
+    let c = -0.4 + 1.8 * 1.05 * 0.5;
+    assert!(near(edge(c, 0.6, 0.8), 0.49, 0.1));
+    assert!(edge(c, 1.0, 0.8) < 0.1);
+    assert!(edge(c, 0.2, 0.8) > 0.8);
+    // Directions: "r" starts on the left, "l" on the right, "u" at the bottom, "d" at the top,
+    // diagonals at the opposite corner.
+    let first = |o: &str| {
+        let ls = transition_layers("wipe", o, 0.15);
+        let n = of(&ls, Source::New);
+        assert!(!n.is_empty(), "{o}");
+        let cx = n.iter().map(|l| (l.quad[0][0] + l.quad[2][0]) / 2.0).sum::<f64>() / n.len() as f64;
+        let cy = n.iter().map(|l| (l.quad[0][1] + l.quad[2][1]) / 2.0).sum::<f64>() / n.len() as f64;
+        (cx, cy)
+    };
+    assert!(first("r").0 < 0.3 && first("l").0 > 0.7);
+    assert!(first("u").1 > 0.7 && first("d").1 < 0.3);
+    let ru = first("ru");
+    assert!(ru.0 < 0.4 && ru.1 > 0.6, "{ru:?}");
+}
+
+#[test]
+fn split_and_shape_open_from_the_middle() {
+    for o in ["horzOut", "vertOut"] {
+        let ls = transition_layers("split", o, 0.2);
+        let n = of(&ls, Source::New);
+        assert!(n.iter().all(|l| {
+            let c = [(l.quad[0][0] + l.quad[2][0]) / 2.0, (l.quad[0][1] + l.quad[2][1]) / 2.0];
+            if o.starts_with("horz") { (c[1] - 0.5).abs() < 0.4 } else { (c[0] - 0.5).abs() < 0.4 }
+        }));
+    }
+    // Shape In is done with the old slide at half time; Shape Out starts the new one then.
+    assert!(of(&transition_layers("shape", "in", 0.55), Source::Old).is_empty());
+    assert!(of(&transition_layers("shape", "out", 0.45), Source::New).is_empty());
+}
+
+#[test]
+fn dynamic_content_curves() {
+    // Pan: the new content's offset (fraction of the width) at measured times.
+    for (t, off) in [(0.6, 0.134), (0.7, 0.086), (0.8, 0.039), (0.9, 0.011)] {
+        let ls = transition_layers("pan", "l", t);
+        assert!(near(left(of(&ls, Source::NewContent)[0]), off, 0.07), "pan t={t}");
+    }
+    // The backgrounds cross-fade under the moving contents.
+    let ls = transition_layers("pan", "l", 0.5);
+    assert_eq!(ls.first().map(|l| l.source), Some(Source::OldBack));
+    assert!(of(&ls, Source::NewBack)[0].alpha > 0.5);
+    // Ferris Wheel: the old content drops (top edge, slide heights) as measured.
+    for (t, dy) in [(0.147, 0.06), (0.246, 0.17), (0.345, 0.36), (0.444, 0.70)] {
+        let ls = transition_layers("ferris", "l", t);
+        let q = of(&ls, Source::OldContent)[0].quad;
+        let cy = q.iter().map(|p| p[1]).sum::<f64>() / 4.0 - 0.5;
+        assert!(near(cy, dy, 0.08), "ferris t={t}: {cy}");
+    }
+    for k in ["pan", "ferris", "conveyor", "rotate", "window", "orbit", "flythrough"] {
+        assert!(uses_slide_parts(k, ""), "{k}");
+    }
+    assert!(uses_slide_parts("reveal", "smoothlyLeft") && !uses_slide_parts("reveal", "blackLeft"));
+    assert!(!uses_slide_parts("cube", "l") && !uses_slide_parts("push", "l"));
+}
+
+#[test]
+fn cube_turns_toward_the_option() {
+    // Cube Left at the middle: the shared edge is near the middle, the old face on the left.
+    let ls = transition_frame("cube", "l", 0.5, A);
+    let (o, n) = (of(&ls, Source::Old)[0], of(&ls, Source::New)[0]);
+    let o_right = o.quad.iter().map(|p| p[0]).fold(f64::NEG_INFINITY, f64::max);
+    assert!(near(o_right, left(n), 0.02), "shared edge: {o_right} vs {}", left(n));
+    assert!(o_right > 0.3 && o_right < 0.7);
+    // Up: the new face comes from below.
+    let ls = transition_frame("cube", "u", 0.5, A);
+    assert!(top(of(&ls, Source::New)[0]) > top(of(&ls, Source::Old)[0]));
+}
+
+#[test]
+fn switch_swaps_the_cards_past_halfway() {
+    let order = |t: f64| {
+        let ls = transition_frame("switch", "l", t, A);
+        let pos = |s: Source| ls.iter().position(|l| l.source == s);
+        (pos(Source::Old), pos(Source::New))
+    };
+    let (o, n) = order(0.3);
+    assert!(o > n, "old in front early");
+    let (o, n) = order(0.8);
+    assert!(n > o, "new in front late");
+}
+
+#[test]
+fn clock_hand_sweeps_at_constant_speed() {
+    // The share of the slide covered grows linearly.
+    let area = |t: f64| {
+        let ls = transition_layers("clock", "clockwise", t);
+        of(&ls, Source::New)
+            .iter()
+            .map(|l| {
+                let [a, b, c, _] = l.quad;
+                ((b[0] - a[0]) * (c[1] - a[1]) - (c[0] - a[0]) * (b[1] - a[1])).abs() / 2.0 * (l.fade[0] + l.fade[1] + l.fade[2]) / 3.0
+            })
+            .sum::<f64>()
+    };
+    let (a1, a2, a3) = (area(0.25), area(0.5), area(0.75));
+    assert!(near(a2 - a1, a3 - a2, 0.08), "{a1} {a2} {a3}");
+    assert!(near(a2, 0.5, 0.08), "{a2}");
+}
+
+#[test]
+fn options_change_the_frame() {
+    // Every option of a transition draws something different from its other options midway.
+    for (id, _, _, _, opts) in TRANSITIONS {
+        if matches!(*id, "morph" | "none" | "random") || opts.len() < 2 {
+            continue;
+        }
+        for (i, a) in opts.iter().enumerate() {
+            for b in opts.iter().skip(i + 1) {
+                let differs = [0.2, 0.35, 0.5, 0.8].iter().any(|t| transition_layers(id, a, *t) != transition_layers(id, b, *t));
+                assert!(differs, "{id}: {a} vs {b}");
+            }
+        }
+    }
+}
+
+#[test]
+fn frames_stay_cheap() {
+    // Per frame, the show draws these meshes from cached slide textures: keep them small.
+    for (id, _, _, _, opts) in TRANSITIONS {
+        let mut options: Vec<&str> = opts.to_vec();
+        options.push("");
+        for o in options {
+            for t in [0.1, 0.3, 0.5, 0.7, 0.9] {
+                let tris: usize = transition_frame(id, o, t, A).iter().map(|l| crate::layer_mesh(l).1.len()).sum();
+                assert!(tris < 30_000, "{id}/{o} t={t}: {tris} triangles");
+            }
+        }
+    }
+}
+
+#[test]
+fn hostile_aspects_are_safe() {
+    for a in [f64::NAN, 0.0, -3.0, 1e9, f64::INFINITY] {
+        for (id, ..) in TRANSITIONS {
+            for l in transition_frame(id, "", 0.4, a) {
+                assert!(l.quad.iter().all(|p| p[0].is_finite() && p[1].is_finite()));
+                assert!(l.fade.iter().all(|f| (0.0..=1.0).contains(f)));
+            }
+        }
+    }
+    assert!(near(ss(0.5), 0.5, 1e-12));
+}

crates/engine/src/cmd/file.rs

@@ -15,7 +15,16 @@ pub fn specs() -> Vec<CommandSpec> {
         cmd!(noundo "file.saveAs", "Save As…", ["File"], Some("Cmd+Shift+S"), "{path, format?}", has_doc, save_as),
         cmd!(noundo "file.saveTemplate", "Save as Template…", ["File"], None, "{path}", has_doc, save_as),
         cmd!(query "file.saveBytes", "Save to Data", [], None, "{format?: deckcraft|pptx} → {data: base64}", has_doc, save_bytes_cmd),
-        cmd!(noundo "file.export", "Export…", ["File"], None, "{path, format: png|jpeg|pptx|deckcraft|outline|pdf, slide?: index, all?: bool, scale?: px per pt; pdf: layout?: slides|notes|handouts, perPage?: 1|2|3|4|6|9, dpi?, slides?: [index], includeHidden?, textLayer?, frame?}", has_doc, export),
+        cmd!(noundo "file.export", "Export…", ["File"], None, "{path, format: png|jpeg|pptx|deckcraft|outline|pdf, slide?: index, all?: bool, scale?: px per pt; pdf: layout?: slides|notes|handouts, perPage?: 1|2|3|4|6|9, dpi?, slides?: [index] | \"1-3,5\", includeHidden?, textLayer?, frame?}", has_doc, export),
+        cmd!(
+            query "file.info",
+            "Info",
+            ["File"],
+            None,
+            "{} → {title, path, format, dirty, slides, hiddenSlides, sections, bytes?, properties}",
+            has_doc,
+            info
+        ),
         cmd!(query "file.render", "Render Slide", [], None, "{slide?: index, scale?, edit?: bool} → {png: base64, width, height}", has_doc, render),
         cmd!(noundo "file.close", "Close", ["File"], Some("Cmd+W"), "{}", has_doc, close),
         cmd!(
@@ -118,26 +127,59 @@ pub fn save_bytes(doc: &Presentation, format: &str) -> Result<Vec<u8>> {
     }
 }
 
-/// PDF options from command params: `{layout: slides|notes|handouts, perPage, dpi, slides: [i],
-/// includeHidden, textLayer, frame}`.
-pub fn pdf_options(p: &Value) -> deckcraft_pdf::PdfOptions {
+/// PDF options from command params: `{layout: slides|notes|handouts, perPage, dpi, slides,
+/// includeHidden, textLayer, frame}` for a presentation of `count` slides. `slides` is a list of
+/// 0-based indices or a range as typed in PowerPoint's Print page (`"1-3, 5"`, 1-based).
+pub fn pdf_options(p: &Value, count: usize) -> Result<deckcraft_pdf::PdfOptions> {
     let mut o = deckcraft_pdf::PdfOptions { layout: deckcraft_pdf::PageLayout::Slides, ..Default::default() };
     o.layout = match str_param(p, "layout").unwrap_or("slides") {
         "notes" => deckcraft_pdf::PageLayout::Notes,
-        "handouts" => deckcraft_pdf::PageLayout::Handouts { per_page: usize_param(p, "perPage").unwrap_or(6).min(9) as u8 },
+        "handouts" => deckcraft_pdf::PageLayout::Handouts { per_page: usize_param(p, "perPage").unwrap_or(6).clamp(1, 9) as u8 },
         _ => deckcraft_pdf::PageLayout::Slides,
     };
     o.dpi = f64_or(p, "dpi", o.dpi).clamp(36.0, 600.0);
-    o.slides = p.get("slides").and_then(Value::as_array).map(|a| a.iter().filter_map(|v| v.as_u64().map(|x| x as usize)).collect());
+    o.slides = match p.get("slides") {
+        Some(Value::Array(a)) => Some(a.iter().filter_map(|v| v.as_u64().map(|x| x as usize)).filter(|i| *i < count).collect()),
+        Some(Value::String(text)) if !text.trim().is_empty() => Some(parse_slide_range(text, count)?),
+        _ => None,
+    };
     o.include_hidden = bool_or(p, "includeHidden", false);
     o.text_layer = bool_or(p, "textLayer", true);
     o.frame_slides = bool_or(p, "frame", true);
-    o
+    Ok(o)
+}
+
+/// A slide range as typed in the Print page's Slides box (`"1-3, 5"`; 1-based, either separator
+/// `,` or `;`, ranges either way round) → 0-based indices in order, without repeats. Numbers past
+/// the last slide or a range that isn't numbers is an error, as in PowerPoint.
+pub fn parse_slide_range(text: &str, count: usize) -> Result<Vec<usize>> {
+    let invalid = || bad("file.export", format!("“{text}” isn't a valid slide range: use numbers and ranges such as 1-3, 5"));
+    let mut out: Vec<usize> = vec![];
+    for part in text.split([',', ';']).map(str::trim).filter(|p| !p.is_empty()) {
+        let (a, b) = match part.split_once('-') {
+            Some((a, b)) => (a.trim(), b.trim()),
+            None => (part, part),
+        };
+        let (a, b) = (a.parse::<usize>().map_err(|_| invalid())?, b.parse::<usize>().map_err(|_| invalid())?);
+        let (lo, hi) = (a.min(b), a.max(b));
+        if lo == 0 || hi > count {
+            return Err(bad("file.export", format!("the presentation has {count} slides; “{part}” is outside them")));
+        }
+        for i in lo - 1..hi {
+            if !out.contains(&i) {
+                out.push(i);
+            }
+        }
+    }
+    if out.is_empty() {
+        return Err(invalid());
+    }
+    Ok(out)
 }
 
 /// PDF bytes for `doc` with [`pdf_options`] from `p`.
 pub fn pdf_bytes(doc: &Presentation, p: &Value) -> Result<Vec<u8>> {
-    deckcraft_pdf::export(doc, &pdf_options(p)).map_err(|e| EngineError::Other(e.to_string()))
+    deckcraft_pdf::export(doc, &pdf_options(p, doc.slides.len())?).map_err(|e| EngineError::Other(e.to_string()))
 }
 
 pub fn format_for_path(path: &str) -> &'static str {
@@ -264,7 +306,7 @@ fn export(s: &mut Session, p: &Value) -> Result<Value> {
             Ok(json!({"files": written}))
         }
         "pdf" => {
-            let bytes = deckcraft_pdf::export(&st.doc, &pdf_options(p)).map_err(|e| EngineError::Other(e.to_string()))?;
+            let bytes = pdf_bytes(&st.doc, p)?;
             write_file(&path, &bytes)?;
             Ok(json!({"path": path, "bytes": bytes.len()}))
         }
@@ -276,6 +318,27 @@ fn export(s: &mut Session, p: &Value) -> Result<Value> {
     }
 }
 
+/// File › Info: what the Info page shows about the active presentation.
+fn info(s: &mut Session, _p: &Value) -> Result<Value> {
+    let st = s.doc()?;
+    let doc = &st.doc;
+    #[cfg(not(target_arch = "wasm32"))]
+    let bytes = st.path.as_ref().and_then(|p| std::fs::metadata(p).ok()).map(|m| m.len());
+    #[cfg(target_arch = "wasm32")]
+    let bytes: Option<u64> = None;
+    Ok(json!({
+        "title": st.title(),
+        "path": st.path,
+        "format": st.path.as_deref().map(format_for_path),
+        "dirty": st.is_dirty(),
+        "slides": doc.slides.len(),
+        "hiddenSlides": doc.slides.iter().filter(|sl| sl.hidden).count(),
+        "sections": doc.sections.len(),
+        "bytes": bytes,
+        "properties": serde_json::to_value(&doc.props).unwrap_or_default(),
+    }))
+}
+
 fn close(s: &mut Session, _p: &Value) -> Result<Value> {
     if let Some(i) = s.active_index() {
         s.close_document(i);

crates/engine/src/cmd/shape.rs

@@ -261,7 +261,7 @@ pub(crate) fn gradient_param(v: &Value) -> Option<Gradient> {
             scaled: false,
         },
     };
-    Some(Gradient { stops, shape, rotate_with_shape: v.get("rotateWithShape").and_then(Value::as_bool).unwrap_or(true) })
+    Some(Gradient { tile: [0.0; 4], stops, shape, rotate_with_shape: v.get("rotateWithShape").and_then(Value::as_bool).unwrap_or(true) })
 }
 
 fn fill(s: &mut Session, p: &Value) -> Result<Value> {

crates/engine/src/tests.rs

@@ -774,3 +774,64 @@ fn ime_composition_underlines_follow_the_text() {
     s.commit_text("日本語").unwrap();
     assert!(cmd::text::composition_underlines(s.doc().unwrap()).is_empty());
 }
+
+/// File › Info (#76): the active presentation's name, location, counts and properties.
+#[test]
+fn file_info_reports_the_presentation() {
+    let mut s = session();
+    s.execute("slide.new", &json!({})).unwrap();
+    s.execute("slide.new", &json!({})).unwrap();
+    s.execute("slide.go", &json!({"index": 1})).unwrap();
+    s.execute("slide.hide", &json!({})).unwrap();
+    s.execute("file.properties", &json!({"title": "Quarterly", "author": "Ada"})).unwrap();
+    let v = s.execute("file.info", &json!({})).unwrap();
+    assert_eq!(v["slides"], 3);
+    assert_eq!(v["hiddenSlides"], 1);
+    assert_eq!(v["path"], serde_json::Value::Null);
+    assert_eq!(v["dirty"], true);
+    assert_eq!(v["properties"]["title"], "Quarterly");
+    assert_eq!(v["properties"]["author"], "Ada");
+    assert!(v["title"].as_str().is_some_and(|t| !t.is_empty()));
+    // A query: no undo step, and nothing changes.
+    let before = s.doc().unwrap().history.undo.len();
+    s.execute("file.info", &json!({})).unwrap();
+    assert_eq!(s.doc().unwrap().history.undo.len(), before);
+    // Saved to disk, it reports where and how big.
+    let dir = std::env::temp_dir().join(format!("deckcraft-info-{}", std::process::id()));
+    std::fs::create_dir_all(&dir).unwrap();
+    let path = dir.join("Info test.pptx").to_string_lossy().to_string();
+    s.execute("file.saveAs", &json!({"path": path})).unwrap();
+    let v = s.execute("file.info", &json!({})).unwrap();
+    assert_eq!(v["path"], path.as_str());
+    assert_eq!(v["format"], "pptx");
+    assert_eq!(v["dirty"], false);
+    assert!(v["bytes"].as_u64().is_some_and(|b| b > 0));
+    let _ = std::fs::remove_dir_all(&dir);
+    // Nothing open: an error, not a panic.
+    let mut empty = Session::new();
+    assert!(empty.execute("file.info", &json!({})).is_err());
+}
+
+/// The Print page's Slides box (#76): PowerPoint-style ranges, 1-based.
+#[test]
+fn slide_ranges_parse_like_powerpoints_print_box() {
+    use cmd::file::parse_slide_range as r;
+    assert_eq!(r("1-3, 5", 6).unwrap(), vec![0, 1, 2, 4]);
+    assert_eq!(r("3-1;2", 6).unwrap(), vec![0, 1, 2], "reversed ranges and repeats");
+    assert_eq!(r(" 6 ", 6).unwrap(), vec![5]);
+    assert!(r("7", 6).is_err(), "past the last slide");
+    assert!(r("0", 6).is_err());
+    assert!(r("a-b", 6).is_err());
+    assert!(r(" , ", 6).is_err());
+    assert!(r("1-99999999999999999999999", 6).is_err(), "hostile numbers are refused");
+    // file.export takes the same text for a PDF.
+    let mut s = session();
+    s.execute("slide.new", &json!({})).unwrap();
+    let doc = s.doc().unwrap().doc.clone();
+    let one = cmd::file::pdf_bytes(&doc, &json!({"slides": "2"})).unwrap();
+    let both = cmd::file::pdf_bytes(&doc, &json!({"slides": "1-2"})).unwrap();
+    assert!(one.len() < both.len());
+    assert!(cmd::file::pdf_bytes(&doc, &json!({"slides": "5"})).is_err());
+    let opts = cmd::file::pdf_options(&json!({"slides": [0, 7, 1]}), 2).unwrap();
+    assert_eq!(opts.slides, Some(vec![0, 1]), "indices past the end are dropped");
+}

crates/fonts/src/fallback.rs

@@ -17,6 +17,11 @@ use skrifa::raw::TableProvider;
 use crate::script::{ScriptTag, script_of};
 use crate::{CRAFT_FONTS, FontDb, FontFace};
 
+/// Variation selector 15: text presentation.
+const TEXT_SELECTOR: char = '\u{FE0E}';
+/// Combining enclosing keycap.
+const KEYCAP: char = '\u{20E3}';
+
 /// Characters that never decide a face: they're drawn by whatever face the cluster gets.
 fn ignorable(c: char) -> bool {
     c.is_whitespace()
@@ -24,20 +29,72 @@ fn ignorable(c: char) -> bool {
         || matches!(c as u32, 0x200B..=0x200F | 0x202A..=0x202E | 0x2060..=0x2069 | 0xFE00..=0xFE0F | 0xFEFF | 0xE0100..=0xE01EF)
 }
 
-/// Is the cluster an emoji drawn in colour: a pictograph that defaults to emoji presentation, or
-/// any sequence with an emoji presentation selector (U+FE0F), a zero-width joiner between
-/// pictographs, a skin tone modifier, regional indicators (flags) or a keycap?
+/// Is the cluster an emoji drawn in colour: a pictograph that defaults to emoji presentation
+/// (Unicode's Emoji_Presentation, including BMP ones such as ⭐ ✅ ☔ ⌚ ⏩), or a sequence with an
+/// emoji presentation selector (U+FE0F), a zero-width joiner between pictographs, a skin tone
+/// modifier or regional indicators (flags)? Keycaps ("1️⃣") are not: PowerPoint draws them as text
+/// (an outlined key), as it draws ♥ ✔ ☎ ⬆ ▶ without a selector.
 pub fn is_emoji_cluster(cluster: &[char]) -> bool {
-    if cluster.contains(&'\u{FE0E}') {
+    if cluster.contains(&'\u{FE0E}') || cluster.contains(&'\u{20E3}') {
         return false;
     }
     let pictographic = |c: char| matches!(c as u32, 0x1F000..=0x1FAFF | 0x2600..=0x27BF | 0x2B00..=0x2BFF | 0x2190..=0x21FF | 0x2300..=0x23FF);
-    let default_emoji =
-        |c: char| matches!(c as u32, 0x1F300..=0x1F64F | 0x1F680..=0x1F6FF | 0x1F900..=0x1F9FF | 0x1FA70..=0x1FAFF | 0x1F1E6..=0x1F1FF);
+    let default_emoji = |c: char| {
+        matches!(
+            c as u32,
+            0x1F300..=0x1F64F
+                | 0x1F680..=0x1F6FF
+                | 0x1F900..=0x1F9FF
+                | 0x1FA70..=0x1FAFF
+                | 0x1F1E6..=0x1F1FF
+                | 0x1F004
+                | 0x1F0CF
+                | 0x1F18E
+                | 0x1F191..=0x1F19A
+                | 0x1F201
+                | 0x1F21A
+                | 0x1F22F
+                | 0x1F232..=0x1F236
+                | 0x1F238..=0x1F23A
+                | 0x1F250..=0x1F251
+                | 0x231A..=0x231B
+                | 0x23E9..=0x23EC
+                | 0x23F0
+                | 0x23F3
+                | 0x25FD..=0x25FE
+                | 0x2614..=0x2615
+                | 0x2648..=0x2653
+                | 0x267F
+                | 0x2693
+                | 0x26A1
+                | 0x26AA..=0x26AB
+                | 0x26BD..=0x26BE
+                | 0x26C4..=0x26C5
+                | 0x26CE
+                | 0x26D4
+                | 0x26EA
+                | 0x26F2..=0x26F3
+                | 0x26F5
+                | 0x26FA
+                | 0x26FD
+                | 0x2705
+                | 0x270A..=0x270B
+                | 0x2728
+                | 0x274C
+                | 0x274E
+                | 0x2753..=0x2755
+                | 0x2757
+                | 0x2795..=0x2797
+                | 0x27B0
+                | 0x27BF
+                | 0x2B1B..=0x2B1C
+                | 0x2B50
+                | 0x2B55
+        )
+    };
     cluster.iter().any(|&c| default_emoji(c))
-        || (cluster.contains(&'\u{FE0F}') && cluster.iter().any(|&c| pictographic(c) || c.is_ascii_digit() || c == '#' || c == '*'))
+        || (cluster.contains(&'\u{FE0F}') && cluster.iter().any(|&c| pictographic(c)))
         || (cluster.contains(&'\u{200D}') && cluster.iter().any(|&c| pictographic(c)))
-        || cluster.contains(&'\u{20E3}')
 }
 
 /// Does `face` draw every character of the cluster?
@@ -86,12 +143,13 @@ impl FontDb {
         if let Some(f) = chain.iter().find(|f| covers_cluster(f, cluster)) {
             return f.clone();
         }
-        // Text presentation (U+FE0E): a plain face, not a colour emoji one.
-        if cluster.contains(&'\u{FE0E}') {
-            let faces = self.read_faces();
-            if let Some(f) = faces.iter().find(|f| !f.is_color() && covers_cluster(f, cluster)) {
-                return f.clone();
-            }
+        // Text presentation (U+FE0E) and keycaps: a plain face, not a colour emoji one.
+        let text_style = cluster.contains(&TEXT_SELECTOR) || cluster.contains(&KEYCAP);
+        if text_style
+            && let Some(key) = cluster.iter().copied().find(|c| !ignorable(*c))
+            && let Some(f) = self.plain_face_for(key, cluster)
+        {
+            return f;
         }
         let first = || chain.first().cloned().unwrap_or_else(|| self.face(crate::DEFAULT_FAMILY, style));
         let Some(key) = cluster.iter().copied().find(|c| !ignorable(*c)) else { return first() };
@@ -124,11 +182,23 @@ impl FontDb {
             }
         }
         let exclude = chain.first().map(|f| f.id()).unwrap_or(u32::MAX);
-        match self.fallback_for(key, exclude) {
+        let f = match self.fallback_for(key, exclude) {
             Some(f) if covers_cluster(&f, cluster) => f,
             Some(f) if chain.iter().all(|c| !c.covers(key)) => f,
-            _ => first(),
+            // A letter with marks the run's font lacks (stacked combining marks): a loaded plain
+            // face that draws the whole cluster, as PowerPoint draws the marks, before the run's
+            // font with missing-glyph boxes.
+            _ => self.read_faces().iter().find(|f| !f.is_color() && covers_cluster(f, cluster)).cloned().unwrap_or_else(first),
+        };
+        // A pictograph that defaults to text presentation (⚠ ♥ ⬆ ▶) whose first fallback is the
+        // colour emoji font: PowerPoint draws it from a plain symbol font.
+        if f.is_color()
+            && !is_emoji_cluster(cluster)
+            && let Some(plain) = self.plain_face_for(key, cluster)
+        {
+            return plain;
         }
+        f
     }
 
     /// An installed (non-bundled) face covering the cluster, loading one from the system catalog

crates/fonts/src/fontdb.rs

@@ -134,6 +134,12 @@ pub struct FontFace {
     /// Windows ascent over the Windows ascent plus descent (OS/2 `usWinAscent`/`usWinDescent`),
     /// the split PowerPoint uses (computed by `line_split`).
     pub line_split: f64,
+    /// Underline position (top edge, below the baseline) and thickness in font units (`post`
+    /// table; 0.1 and 0.05 em when the font has none). PowerPoint draws single underlines there.
+    pub underline: (f64, f64),
+    /// Strikethrough position (top edge, above the baseline) and thickness in font units (OS/2;
+    /// 0.26 and 0.05 em when the font has none). PowerPoint draws single strikethroughs there.
+    pub strikeout: (f64, f64),
     pub shaper: harfrust::ShaperData,
     /// Variable fonts: the named instance's axis settings (user units; empty = default instance),
     /// the normalised location and the shaper's view of it.
@@ -586,6 +592,8 @@ fn make_face(bytes: FontBytes, index: u32, family: String, style: String, coords
         cap_height: m.cap_height.map(|v| v as f64).filter(|v| *v > 0.0).unwrap_or(m.ascent as f64 * 0.72),
         x_height: m.x_height.map(|v| v as f64).filter(|v| *v > 0.0).unwrap_or(m.ascent as f64 * 0.5),
         line_split: line_split(&f, m.ascent as f64, -(m.descent as f64), m.units_per_em.max(1) as f64),
+        underline: underline_metrics(m.underline, m.units_per_em.max(1) as f64),
+        strikeout: strikeout_metrics(m.strikeout, m.units_per_em.max(1) as f64),
         shaper,
         coords,
         location,
@@ -597,6 +605,30 @@ fn make_face(bytes: FontBytes, index: u32, family: String, style: String, coords
     })
 }
 
+/// The underline's top edge below the baseline and its thickness, font units, from the `post`
+/// table (its position is the top edge: Arial's -217/2048 is where PowerPoint's underline starts,
+/// 10 px below the baseline at 96 pt); fonts without a usable one get 0.1 em and 0.05 em.
+fn underline_metrics(d: Option<skrifa::metrics::Decoration>, upem: f64) -> (f64, f64) {
+    match d {
+        Some(d) if d.thickness > 0.0 && (d.thickness as f64) < upem * 0.3 && (d.offset as f64).abs() < upem * 0.5 => {
+            (-(d.offset as f64), d.thickness as f64)
+        }
+        _ => (upem * 0.1, upem * 0.05),
+    }
+}
+
+/// The strikethrough's top edge above the baseline and its thickness, font units, from OS/2 (its
+/// position is the top edge: Arial's 530/2048 is where PowerPoint's strikethrough starts, 25 px
+/// above the baseline at 96 pt); fonts without a usable one get 0.26 em and 0.05 em.
+fn strikeout_metrics(d: Option<skrifa::metrics::Decoration>, upem: f64) -> (f64, f64) {
+    match d {
+        Some(d) if d.thickness > 0.0 && (d.thickness as f64) < upem * 0.3 && d.offset > 0.0 && (d.offset as f64) < upem => {
+            (d.offset as f64, d.thickness as f64)
+        }
+        _ => (upem * 0.26, upem * 0.05),
+    }
+}
+
 /// The named style part of a style with axis settings (`Bold {wght:650}` → `Bold`).
 pub fn base_style(style: &str) -> &str {
     style.split('{').next().unwrap_or(style).trim()
@@ -1060,6 +1092,79 @@ impl FontDb {
         None
     }
 
+    /// A loaded plain (not colour) face drawing all of `cluster`, loading an installed plain font
+    /// that covers `key` if none is loaded yet. Misses are remembered.
+    pub(crate) fn plain_face_for(&self, key: char, cluster: &[char]) -> Option<Arc<FontFace>> {
+        // Symbol fonts first (PowerPoint draws ⚠ ♥ ⬆ from the system's symbol font), then the
+        // usual fallback families in order, then any other.
+        let rank = |f: &FontFace| {
+            if f.family.contains("Symbol") {
+                return 0;
+            }
+            #[cfg(not(target_arch = "wasm32"))]
+            if let Some(i) = SYSTEM_FALLBACKS.iter().position(|s| s.eq_ignore_ascii_case(&f.family)) {
+                return i + 1;
+            }
+            1000
+        };
+        let pick = |db: &FontDb| {
+            let faces = db.read_faces();
+            let mut v: Vec<&Arc<FontFace>> = faces.iter().filter(|f| !f.is_color() && crate::covers_cluster(f, cluster)).collect();
+            v.sort_by_key(|f| (rank(f), f.italic, (f.weight - 400.0).abs() as i32));
+            v.first().map(|f| (*f).clone())
+        };
+        #[cfg(not(target_arch = "wasm32"))]
+        {
+            let cataloged: Vec<String> = self.read_catalog().iter().map(|e| e.family.clone()).collect();
+            for fam in SYSTEM_FALLBACKS.iter().filter(|f| f.contains("Symbol")) {
+                if !self.is_loaded(fam) && cataloged.iter().any(|f| f.eq_ignore_ascii_case(fam)) {
+                    self.load_cataloged(fam);
+                }
+            }
+        }
+        if let Some(f) = pick(self) {
+            return Some(f);
+        }
+        #[cfg(not(target_arch = "wasm32"))]
+        if self.system_plain_fallback(key) {
+            return pick(self);
+        }
+        let _ = key;
+        None
+    }
+
+    /// Load an installed font without colour tables covering `c`. True if one was loaded.
+    #[cfg(not(target_arch = "wasm32"))]
+    fn system_plain_fallback(&self, c: char) -> bool {
+        static MISSES: Mutex<Option<std::collections::HashSet<char>>> = Mutex::new(None);
+        if c.is_control() || c.is_whitespace() {
+            return false;
+        }
+        if !self.sys.lock().unwrap_or_else(|e| e.into_inner()).enabled {
+            return false;
+        }
+        if MISSES.lock().unwrap_or_else(|e| e.into_inner()).get_or_insert_with(Default::default).contains(&c) {
+            return false;
+        }
+        let mut paths: Vec<std::path::PathBuf> = self.read_catalog().iter().map(|e| e.path.clone()).collect();
+        paths.sort();
+        paths.dedup();
+        for p in paths {
+            if std::fs::metadata(&p).map(|m| m.len() > 40 << 20).unwrap_or(true) {
+                continue;
+            }
+            let Ok(data) = std::fs::read(&p) else { continue };
+            let hit = enumerate_faces(&data).iter().any(|(i, _, _, _)| {
+                !has_color_tables(&data, *i) && skrifa::FontRef::from_index(&data, *i).is_ok_and(|f| f.charmap().map(c).is_some())
+            });
+            if hit && self.add_font(data) > 0 {
+                return true;
+            }
+        }
+        MISSES.lock().unwrap_or_else(|e| e.into_inner()).get_or_insert_with(Default::default).insert(c);
+        false
+    }
+
     /// Load an installed colour font covering `c`. True if one was loaded.
     #[cfg(not(target_arch = "wasm32"))]
     fn system_color_fallback(&self, c: char) -> bool {

crates/fonts/src/lib.rs

@@ -141,10 +141,15 @@ mod tests {
     #[test]
     fn emoji_clusters_are_recognised() {
         let c = |s: &str| s.chars().collect::<Vec<char>>();
-        for yes in ["😀", "👍🏽", "❤\u{FE0F}", "👨\u{200D}👩\u{200D}👧", "🇯🇵", "1\u{FE0F}\u{20E3}", "🏳\u{FE0F}\u{200D}🌈"] {
+        // As PowerPoint draws them: emoji-presentation characters (⭐ ✅ ☔ ⌚ ⏩) in colour even
+        // without a selector, text-presentation ones (♥ ✔ ☎ ⬆ ▶) as text unless U+FE0F asks, and
+        // keycaps always as text.
+        for yes in ["😀", "👍🏽", "❤\u{FE0F}", "👨\u{200D}👩\u{200D}👧", "🇯🇵", "🏳\u{FE0F}\u{200D}🌈", "⭐", "✅", "☔", "⌚", "⏩", "🀄"]
+        {
             assert!(is_emoji_cluster(&c(yes)), "{yes:?}");
         }
-        for no in ["a", "1", "❤", "☺\u{FE0E}", "😀\u{FE0E}", "字", "→"] {
+        for no in ["a", "1", "❤", "☺\u{FE0E}", "😀\u{FE0E}", "字", "→", "♥", "✔", "☎", "⬆", "▶", "1\u{FE0F}\u{20E3}", "#\u{20E3}"]
+        {
             assert!(!is_emoji_cluster(&c(no)), "{no:?}");
         }
     }

crates/geom/src/preset.rs

@@ -6,7 +6,7 @@
 //! geometry table. Adjust values use the file convention: ratios in 1/100 000 of the shorter side (or
 //! of the width/height), angles in 1/60 000 degree.
 
-use kurbo::{Arc, BezPath, Point, Rect, Shape as _, Vec2};
+use kurbo::{Arc, BezPath, Point, Rect, Vec2};
 use serde::{Deserialize, Serialize};
 
 mod extra;
@@ -339,6 +339,45 @@ pub fn info(name: &str) -> Option<&'static PresetInfo> {
     CATALOG.iter().find(|p| p.name == name)
 }
 
+/// Whether PowerPoint joins this preset's outline with sharp (miter) corners when the line names
+/// no join (it rounds them otherwise). Observed per preset on its export: the plus, the right,
+/// up and down block arrows (not the left one), chevrons, stars from five points up, the
+/// equation shapes, curved ribbons and the action buttons are mitred.
+pub fn mitred_by_default(name: &str) -> bool {
+    matches!(
+        name,
+        "plus"
+            | "rightArrow"
+            | "upArrow"
+            | "downArrow"
+            | "upDownArrow"
+            | "leftUpArrow"
+            | "bentUpArrow"
+            | "stripedRightArrow"
+            | "notchedRightArrow"
+            | "chevron"
+            | "leftArrowCallout"
+            | "leftRightArrowCallout"
+            | "upDownArrowCallout"
+            | "quadArrowCallout"
+            | "mathPlus"
+            | "mathMinus"
+            | "mathMultiply"
+            | "mathEqual"
+            | "mathNotEqual"
+            | "star5"
+            | "star6"
+            | "star8"
+            | "star10"
+            | "star12"
+            | "star16"
+            | "star24"
+            | "star32"
+            | "ellipseRibbon"
+            | "ellipseRibbon2"
+    ) || name.starts_with("actionButton")
+}
+
 pub fn is_line_like(name: &str) -> bool {
     matches!(name, "line" | "straightConnector1" | "bentConnector2" | "bentConnector3" | "curvedConnector3" | "arc")
         || name.starts_with("bentConnector")
@@ -388,6 +427,29 @@ impl Pb {
         self.cur = Point::new(c.x + wr * e.cos(), c.y + hr * e.sin());
         self
     }
+    /// A DrawingML `arcTo`: angles are where the ray from the ellipse's centre at that angle
+    /// meets it (not the ellipse's parameter), so elliptical arcs start and end where the
+    /// standard's shapes expect.
+    fn arc_spec(&mut self, wr: f64, hr: f64, st: f64, sw: f64) -> &mut Self {
+        let par = |a: f64| {
+            let a = a.to_radians();
+            (wr * a.sin()).atan2(hr * a.cos())
+        };
+        let t0 = par(st);
+        let mut d = par(st + sw) - t0;
+        let tau = std::f64::consts::TAU;
+        if sw.abs() >= 360.0 {
+            d = tau.copysign(sw);
+        } else {
+            while sw > 0.0 && d < 0.0 {
+                d += tau;
+            }
+            while sw < 0.0 && d > 0.0 {
+                d -= tau;
+            }
+        }
+        self.arc(wr, hr, t0.to_degrees(), d.to_degrees())
+    }
     fn z(&mut self) -> &mut Self {
         self.p.close_path();
         self
@@ -458,14 +520,25 @@ fn normalize(pts: &[(f64, f64)], w: f64, h: f64) -> Vec<(f64, f64)> {
     pts.iter().map(|(x, y)| ((x - x0) * sx, (y - y0) * sy)).collect()
 }
 
-fn star(n: usize, w: f64, h: f64, inner: f64, normalized: bool) -> Vec<(f64, f64)> {
+/// An n-pointed star as ECMA-376 draws it: points on an ellipse around (hc, vc · vf) with radii
+/// half the box stretched by the preset's `hf` / `vf` (so a five-pointed star fills its box and
+/// looks regular in a square), the inner corners `inner` of the way out.
+fn star(n: usize, w: f64, h: f64, inner: f64) -> Vec<(f64, f64)> {
+    let (hf, vf) = match n {
+        5 => (1.05146, 1.10557),
+        6 => (1.15470, 1.0),
+        7 => (1.02572, 1.05210),
+        10 => (1.05146, 1.0),
+        _ => (1.0, 1.0),
+    };
+    let (rx, ry, cy) = (w / 2.0 * hf, h / 2.0 * vf, h / 2.0 * vf);
     let mut pts = Vec::with_capacity(n * 2);
     for i in 0..n * 2 {
         let a = (-90.0 + 180.0 * i as f64 / n as f64).to_radians();
         let r = if i % 2 == 0 { 1.0 } else { inner };
-        pts.push((r * a.cos(), r * a.sin()));
+        pts.push((w / 2.0 + r * rx * a.cos(), cy + r * ry * a.sin()));
     }
-    if normalized { normalize(&pts, w, h) } else { pts.iter().map(|(x, y)| (w / 2.0 + x * w / 2.0, h / 2.0 + y * h / 2.0)).collect() }
+    pts
 }
 
 #[derive(Clone, Copy)]
@@ -605,6 +678,11 @@ fn double_arrow(vertical: bool, w: f64, h: f64, a1: f64, a2: f64) -> Geometry {
     Geometry { paths: vec![fill(Pb::new().poly(&pts).take())], text_rect: r, handles: vec![], sites: mid_sites(w, h) }
 }
 
+/// Points given in 21600ths of the box (as ECMA-376 defines many fixed shapes), scaled to it.
+fn spec_pts(pts: &[(i32, i32)], w: f64, h: f64) -> Vec<(f64, f64)> {
+    pts.iter().map(|(x, y)| (w * *x as f64 / 21600.0, h * *y as f64 / 21600.0)).collect()
+}
+
 fn simple(path: BezPath, text: Rect, w: f64, h: f64) -> Geometry {
     Geometry { paths: vec![fill(path)], text_rect: text, handles: vec![], sites: mid_sites(w, h) }
 }
@@ -855,7 +933,8 @@ pub fn build(name: &str, w: f64, h: f64, adj: &[f64]) -> Option<Geometry> {
             g
         }
         "can" | "flowChartMagneticDisk" => {
-            let v = if name == "can" { a(0).clamp(0.0, 50000.0 * h / ss.max(1e-9)) } else { 33333.0 * h / ss.max(1e-9) / 2.0 };
+            // The disk's ends are a third of its height (ECMA-376: ellipses of radius h/6).
+            let v = if name == "can" { a(0).clamp(0.0, 50000.0 * h / ss.max(1e-9)) } else { 100000.0 / 3.0 * h / ss.max(1e-9) };
             let eh = ss * v / 100000.0;
             let r = eh / 2.0;
             let body = Pb::new().m(0.0, r).l(0.0, h - r).arc(w / 2.0, r, 180.0, -180.0).l(w, r).arc(w / 2.0, r, 0.0, -180.0).z().take();
@@ -872,7 +951,8 @@ pub fn build(name: &str, w: f64, h: f64, adj: &[f64]) -> Option<Geometry> {
             g
         }
         "flowChartMagneticDrum" => {
-            let r = w / 6.0 / 2.0;
+            // ECMA-376: end ellipses of radius w/6 across.
+            let r = w / 6.0;
             let body = Pb::new().m(r, 0.0).l(w - r, 0.0).arc(r, h / 2.0, 270.0, 180.0).l(r, h).arc(r, h / 2.0, 90.0, 180.0).z().take();
             let side = Pb::new().m(w - r, 0.0).arc(r, h / 2.0, 270.0, -180.0).take();
             Geometry {
@@ -1048,45 +1128,94 @@ pub fn build(name: &str, w: f64, h: f64, adj: &[f64]) -> Option<Geometry> {
             }
         }
         "heart" => {
-            b.m(w / 2.0, h * 0.25);
-            b.c(w * 0.62, h * -0.02, w, h * 0.0, w, h * 0.32);
-            b.c(w, h * 0.6, w * 0.62, h * 0.78, w / 2.0, h);
-            b.c(w * 0.38, h * 0.78, 0.0, h * 0.6, 0.0, h * 0.32);
-            b.c(0.0, h * 0.0, w * 0.38, h * -0.02, w / 2.0, h * 0.25);
-            b.z();
+            // ECMA-376 heart: two cubic curves from the notch at the top to the point.
+            let (dx1, dx2) = (w * 49.0 / 48.0, w * 10.0 / 48.0);
+            let y1 = -h / 3.0;
+            b.m(w / 2.0, h / 4.0)
+                .c(w / 2.0 + dx2, y1, w / 2.0 + dx1, h / 4.0, w / 2.0, h)
+                .c(w / 2.0 - dx1, h / 4.0, w / 2.0 - dx2, y1, w / 2.0, h / 4.0)
+                .z();
             simple(b.take(), Rect::new(w * 0.2, h * 0.25, w * 0.8, h * 0.7), w, h)
         }
         "lightningBolt" => {
-            let pts = normalize(&[(0.36, 0.0), (0.68, 0.0), (0.53, 0.34), (0.79, 0.34), (0.24, 1.0), (0.39, 0.53), (0.15, 0.53)], w, h);
-            simple(b.poly(&pts).take(), Rect::new(w * 0.3, h * 0.35, w * 0.65, h * 0.6), w, h)
+            // ECMA-376 lightningBolt, in 21600ths of the box.
+            let pts = spec_pts(
+                &[
+                    (8472, 0),
+                    (12860, 6080),
+                    (11050, 6797),
+                    (16577, 12007),
+                    (14767, 12877),
+                    (21600, 21600),
+                    (10012, 14915),
+                    (12222, 13987),
+                    (5022, 9705),
+                    (7602, 8382),
+                    (0, 3890),
+                ],
+                w,
+                h,
+            );
+            simple(b.poly(&pts).take(), Rect::new(w * 8757.0 / 21600.0, h * 7637.0 / 21600.0, w * 13917.0 / 21600.0, h * 12963.0 / 21600.0), w, h)
         }
         "sun" => {
-            let k = a(0).clamp(12500.0, 46875.0) / 100000.0;
-            let (cx, cy) = (w / 2.0, h / 2.0);
-            let cr = 0.5 - k;
-            let core = Pb::new().ellipse(cx, cy, w * cr * 0.72, h * cr * 0.72).take();
-            let mut rays = Pb::new();
-            for i in 0..8 {
-                let ang = (i as f64 * 45.0).to_radians();
-                let half = 9f64.to_radians();
-                let rb = cr * 0.72 + 0.06;
-                let tip = (cx + w * 0.5 * ang.cos(), cy + h * 0.5 * ang.sin());
-                let b1 = (cx + w * rb * (ang - half).cos(), cy + h * rb * (ang - half).sin());
-                let b2 = (cx + w * rb * (ang + half).cos(), cy + h * rb * (ang + half).sin());
-                rays.poly(&[tip, b1, b2]);
-            }
-            Geometry {
-                paths: vec![fill(rays.take()), fill(core)],
-                text_rect: Rect::new(w * 0.3, h * 0.3, w * 0.7, h * 0.7),
-                handles: vec![],
-                sites: mid_sites(w, h),
-            }
+            // ECMA-376 sun: eight triangular rays (their bases at fixed fractions of the core's
+            // margin) around a circle of radius 50% - adj.
+            let a = a(0).clamp(12500.0, 46875.0);
+            let g0 = 50000.0 - a;
+            let (g1, g2) = (g0 * 30274.0 / 32768.0, g0 * 12540.0 / 32768.0);
+            let (g10, g11) = ((50000.0 - g1) * 0.75, (50000.0 - g2) * 0.75);
+            let (g12, g13, g14) = (g10 + 3662.0, g11 + 3662.0, g11 + 12500.0);
+            let (g15, g16, g17, g18) = (100000.0 - g10, 100000.0 - g12, 100000.0 - g13, 100000.0 - g14);
+            let x = |g: f64| w * g / 100000.0;
+            let y = |g: f64| h * g / 100000.0;
+            let (ox1, oy1, ox2, oy2) = (w * 18436.0 / 21600.0, h * 3163.0 / 21600.0, w * 3163.0 / 21600.0, h * 18436.0 / 21600.0);
+            let (hc, vc) = (w / 2.0, h / 2.0);
+            b.poly(&[(w, vc), (x(g15), y(g18)), (x(g15), y(g14))]);
+            b.poly(&[(ox1, oy1), (x(g16), y(g13)), (x(g17), y(g12))]);
+            b.poly(&[(hc, 0.0), (x(g18), y(g10)), (x(g14), y(g10))]);
+            b.poly(&[(ox2, oy1), (x(g13), y(g12)), (x(g12), y(g13))]);
+            b.poly(&[(0.0, vc), (x(g10), y(g14)), (x(g10), y(g18))]);
+            b.poly(&[(ox2, oy2), (x(g12), y(g17)), (x(g13), y(g16))]);
+            b.poly(&[(hc, h), (x(g14), y(g15)), (x(g18), y(g15))]);
+            b.poly(&[(ox1, oy2), (x(g17), y(g16)), (x(g16), y(g17))]);
+            b.ellipse(hc, vc, x(g0), y(g0));
+            let g7 = g0 * 23170.0 / 32768.0;
+            let mut g = simple(b.take(), Rect::new(x(50000.0 - g7), y(50000.0 - g7), x(50000.0 + g7), y(50000.0 + g7)), w, h);
+            g.handles.push(Handle::new(0, Point::new(0.0, vc), Vec2::new(w / 100000.0, 0.0), a, 12500.0, 46875.0));
+            g
         }
         "moon" => {
+            // ECMA-376 moon: the outer edge is the left half of an ellipse w × h/2 centred on the
+            // right edge; the inner edge an arc through the corners and (adj · w, middle) of a
+            // larger ellipse (rx = g18, ry = dy1) whose centre lies right of that point.
             let k = a(0).clamp(0.0, 87500.0) / 100000.0;
-            let g0 = w * k;
-            b.m(w, 0.0).arc(w, h / 2.0, 270.0, -180.0).arc((w - g0).max(0.0), h / 2.0, 90.0, 180.0).z();
-            simple(b.take(), Rect::new(w * 0.1, h * 0.25, w * (1.0 - k).max(0.2) * 0.8, h * 0.75), w, h)
+            let ssf = ss.max(1e-9);
+            let g0 = ss * k;
+            let g1 = (ss - g0).max(1e-9);
+            let g2 = g0 * g0 / g1;
+            let g3 = ss * ss / g1;
+            let g5 = 2.0 * g3 - g2;
+            let g6 = g5 - g0;
+            let dy1 = (g5 / 2.0 - g0) * (h / 2.0) / ssf;
+            let (g0w, g6w) = (g0 * w / ssf, g6 * w / ssf);
+            let rx = (g6w - g0w) / 2.0;
+            let cx = g0w + rx;
+            b.m(w, 0.0).arc(w, h / 2.0, 270.0, -180.0);
+            if rx > 1e-9 && dy1 > 1e-9 {
+                // From the bottom-right corner back up to the top-right through (g0w, h/2).
+                let t0 = ((h / 2.0) / dy1).clamp(-1.0, 1.0).atan2((w - cx) / rx);
+                let t1 = (-(h / 2.0) / dy1).clamp(-1.0, 1.0).atan2((w - cx) / rx) + std::f64::consts::TAU;
+                let arc = Arc::new(Point::new(cx, h / 2.0), Vec2::new(rx, dy1), t0, t1 - t0, 0.0);
+                arc.to_cubic_beziers(0.05, |p1, p2, p| {
+                    b.p.curve_to(p1, p2, p);
+                });
+            }
+            b.z();
+            let g12 = g0 * 9598.0 / 32768.0;
+            let g13 = ss - g12;
+            let dy4 = (ss * ss - g13 * g13).max(0.0).sqrt() * (h / 2.0) / ssf;
+            simple(b.take(), Rect::new(g12 * w / ssf, h / 2.0 - dy4, g0w, h / 2.0 + dy4), w, h)
         }
         "cloud" | "cloudCallout" => cloud(name, w, h, a(0), a(1)),
         "bracketPair" => {
@@ -1124,7 +1253,10 @@ pub fn build(name: &str, w: f64, h: f64, adj: &[f64]) -> Option<Geometry> {
             if name == "rightBracket" {
                 path.apply_affine(kurbo::Affine::new([-1.0, 0.0, 0.0, 1.0, w, 0.0]));
             }
-            Geometry { paths: vec![stroke_only(path)], text_rect: full, handles: vec![], sites: mid_sites(w, h) }
+            // Filled (when the shape has a fill) out to the straight side, as PowerPoint does.
+            let mut area = path.clone();
+            area.close_path();
+            Geometry { paths: vec![fill_only(area), stroke_only(path)], text_rect: full, handles: vec![], sites: mid_sites(w, h) }
         }
         "leftBrace" | "rightBrace" => {
             let r = (ss * a(0).clamp(0.0, 25000.0 * h / ss.max(1e-9)) / 1e5).min(h / 4.0);
@@ -1136,7 +1268,10 @@ pub fn build(name: &str, w: f64, h: f64, adj: &[f64]) -> Option<Geometry> {
             if name == "rightBrace" {
                 path.apply_affine(kurbo::Affine::new([-1.0, 0.0, 0.0, 1.0, w, 0.0]));
             }
-            Geometry { paths: vec![stroke_only(path)], text_rect: full, handles: vec![], sites: mid_sites(w, h) }
+            // Filled (when the shape has a fill) out to the straight side, as PowerPoint does.
+            let mut area = path.clone();
+            area.close_path();
+            Geometry { paths: vec![fill_only(area), stroke_only(path)], text_rect: full, handles: vec![], sites: mid_sites(w, h) }
         }
         "rightArrow" => arrow(Dir::Right, w, h, a(0), a(1)),
         "leftArrow" => arrow(Dir::Left, w, h, a(0), a(1)),
@@ -1372,18 +1507,45 @@ pub fn build(name: &str, w: f64, h: f64, adj: &[f64]) -> Option<Geometry> {
             }
         }
         "flowChartDocument" => {
-            b.m(0.0, 0.0).l(w, 0.0).l(w, h * 0.8).c(w * 0.7, h * 0.62, w * 0.35, h * 1.08, 0.0, h * 0.88).z();
-            simple(b.take(), Rect::new(0.0, 0.0, w, h * 0.78), w, h)
+            let u = |x: f64, y: f64| (w * x / 21600.0, h * y / 21600.0);
+            let (p1, p2, p3, p4) = (u(21600.0, 17322.0), u(10800.0, 17322.0), u(10800.0, 23922.0), u(0.0, 20172.0));
+            b.m(0.0, 0.0).l(w, 0.0).l(p1.0, p1.1).c(p2.0, p2.1, p3.0, p3.1, p4.0, p4.1).z();
+            simple(b.take(), Rect::new(0.0, 0.0, w, h * 17322.0 / 21600.0), w, h)
         }
         "flowChartMultidocument" => {
-            let (dx, dy) = (w * 0.1, h * 0.1);
-            let mut back = Pb::new();
-            back.poly(&[(2.0 * dx, 0.0), (w, 0.0), (w, h * 0.7), (w - dx * 0.5, h * 0.7), (w - dx * 0.5, dy * 0.5), (2.0 * dx, dy * 0.5)]);
-            back.poly(&[(dx, dy * 0.5), (w - dx * 0.5, dy * 0.5), (w - dx * 0.5, h * 0.78), (w - dx, h * 0.78), (w - dx, dy), (dx, dy)]);
-            let front = Pb::new().m(0.0, dy).l(w - dx, dy).l(w - dx, h * 0.84).c(w * 0.62, h * 0.7, w * 0.32, h * 1.08, 0.0, h * 0.9).z().take();
+            // ECMA-376 multidocument (21600ths): two back pages peeking out above and right of
+            // the front one; the back pages' edges are outlined only where they show.
+            let x = |v: f64| w * v / 21600.0;
+            let y = |v: f64| h * v / 21600.0;
+            let front = |b: &mut Pb| {
+                b.m(0.0, y(20782.0))
+                    .c(x(9298.0), y(23542.0), x(9298.0), y(18022.0), x(18595.0), y(18022.0))
+                    .l(x(18595.0), y(3675.0))
+                    .l(0.0, y(3675.0))
+                    .z();
+            };
+            let mid = |b: &mut Pb| {
+                b.m(x(1532.0), y(3675.0)).l(x(1532.0), y(1815.0)).l(x(20000.0), y(1815.0)).l(x(20000.0), y(16252.0));
+                b.c(x(19298.0), y(16252.0), x(18595.0), y(16352.0), x(18595.0), y(16352.0));
+            };
+            let back = |b: &mut Pb| {
+                b.m(x(2972.0), y(1815.0)).l(x(2972.0), 0.0).l(w, 0.0).l(w, y(14392.0));
+                b.c(x(20800.0), y(14392.0), x(20000.0), y(14467.0), x(20000.0), y(14467.0));
+            };
+            let mut area = Pb::new();
+            front(&mut area);
+            mid(&mut area);
+            area.l(x(18595.0), y(3675.0)).z();
+            back(&mut area);
+            area.l(x(20000.0), y(1815.0)).z();
+            let mut outline = Pb::new();
+            outline.m(0.0, y(3675.0)).l(x(18595.0), y(3675.0)).l(x(18595.0), y(18022.0));
+            outline.c(x(9298.0), y(18022.0), x(9298.0), y(23542.0), 0.0, y(20782.0)).z();
+            mid(&mut outline);
+            back(&mut outline);
             Geometry {
-                paths: vec![fill(back.take()), fill(front)],
-                text_rect: Rect::new(0.0, dy, w - dx, h * 0.8),
+                paths: vec![fill_only(area.take()), stroke_only(outline.take())],
+                text_rect: Rect::new(0.0, y(3675.0), x(18595.0), y(17322.0)),
                 handles: vec![],
                 sites: mid_sites(w, h),
             }
@@ -1401,10 +1563,11 @@ pub fn build(name: &str, w: f64, h: f64, adj: &[f64]) -> Option<Geometry> {
             simple(b.poly(&[(w * 0.2, 0.0), (w, 0.0), (w, h), (0.0, h), (0.0, h * 0.2)]).take(), Rect::new(0.0, h * 0.2, w, h), w, h)
         }
         "flowChartPunchedTape" => {
-            let a1 = h * 0.1;
-            b.m(0.0, a1).c(w * 0.25, a1 * 3.0, w * 0.25, -a1, w / 2.0, a1).c(w * 0.75, a1 * 3.0, w * 0.75, -a1, w, a1).l(w, h - a1);
-            b.c(w * 0.75, h - 3.0 * a1, w * 0.75, h + a1, w / 2.0, h - a1).c(w * 0.25, h - 3.0 * a1, w * 0.25, h + a1, 0.0, h - a1).z();
-            simple(b.take(), Rect::new(0.0, h * 0.2, w, h * 0.8), w, h)
+            // ECMA-376: each long edge is two half-ellipses a quarter of the width wide and a
+            // tenth of the height deep, one bulging in and one out.
+            let (rx, ry) = (w / 4.0, h / 10.0);
+            b.m(0.0, ry).arc(rx, ry, 180.0, -180.0).arc(rx, ry, 180.0, 180.0).l(w, h - ry).arc(rx, ry, 0.0, -180.0).arc(rx, ry, 0.0, 180.0).z();
+            simple(b.take(), Rect::new(0.0, h / 5.0, w, h * 0.8), w, h)
         }
         "flowChartSummingJunction" | "flowChartOr" => {
             let e = Pb::new().ellipse(w / 2.0, h / 2.0, w / 2.0, h / 2.0).take();
@@ -1452,84 +1615,115 @@ pub fn build(name: &str, w: f64, h: f64, adj: &[f64]) -> Option<Geometry> {
             let n: usize = name.trim_start_matches("star").parse().unwrap_or(5);
             let v = a(0).clamp(0.0, 50000.0);
             let inner = v / 50000.0;
-            let normalized = matches!(n, 5 | 7);
-            let mut g = simple(b.poly(&star(n, w, h, inner, normalized)).take(), full.inset(-ss * (0.5 - inner * 0.5) * 0.5), w, h);
+            let mut g = simple(b.poly(&star(n, w, h, inner)).take(), full.inset(-ss * (0.5 - inner * 0.5) * 0.5), w, h);
             g.handles.push(Handle::new(0, Point::new(w / 2.0, h / 2.0), Vec2::new(0.0, -h / 2.0 / 50000.0), v, 0.0, 50000.0));
             g
         }
-        "irregularSeal1" | "irregularSeal2" => {
-            let pts: &[(f64, f64)] = if name == "irregularSeal1" {
+        "irregularSeal1" => {
+            // ECMA-376 irregularSeal1 ("Explosion: 8 Points"), in 21600ths of the box.
+            let pts = spec_pts(
                 &[
-                    (0.48, 0.18),
-                    (0.62, 0.0),
-                    (0.64, 0.2),
-                    (0.86, 0.1),
-                    (0.78, 0.3),
-                    (1.0, 0.36),
-                    (0.82, 0.5),
-                    (0.94, 0.72),
-                    (0.7, 0.66),
-                    (0.68, 0.9),
-                    (0.54, 0.72),
-                    (0.42, 1.0),
-                    (0.36, 0.74),
-                    (0.14, 0.86),
-                    (0.22, 0.62),
-                    (0.0, 0.6),
-                    (0.18, 0.44),
-                    (0.04, 0.24),
-                    (0.3, 0.3),
-                    (0.26, 0.06),
-                ]
-            } else {
+                    (10800, 5800),
+                    (14522, 0),
+                    (14155, 5325),
+                    (18380, 4457),
+                    (16702, 7315),
+                    (21097, 8137),
+                    (17607, 10475),
+                    (21600, 13290),
+                    (16837, 12942),
+                    (18145, 18095),
+                    (14020, 14457),
+                    (13247, 19737),
+                    (10532, 14935),
+                    (8485, 21600),
+                    (7715, 15627),
+                    (4762, 17617),
+                    (5667, 13937),
+                    (135, 14587),
+                    (3722, 11775),
+                    (0, 8615),
+                    (4627, 7617),
+                    (370, 2295),
+                    (7312, 6320),
+                    (8352, 2295),
+                ],
+                w,
+                h,
+            );
+            simple(b.poly(&pts).take(), Rect::new(w * 4627.0 / 21600.0, h * 6320.0 / 21600.0, w * 16702.0 / 21600.0, h * 13937.0 / 21600.0), w, h)
+        }
+        "irregularSeal2" => {
+            // ECMA-376 irregularSeal2 ("Explosion: 14 Points"), in 21600ths of the box.
+            let pts = spec_pts(
                 &[
-                    (0.5, 0.16),
-                    (0.58, 0.0),
-                    (0.63, 0.18),
-                    (0.78, 0.06),
-                    (0.76, 0.24),
-                    (0.96, 0.2),
-                    (0.86, 0.38),
-                    (1.0, 0.5),
-                    (0.84, 0.58),
-                    (0.92, 0.76),
-                    (0.74, 0.72),
-                    (0.76, 0.94),
-                    (0.6, 0.8),
-                    (0.5, 1.0),
-                    (0.44, 0.8),
-                    (0.28, 0.94),
-                    (0.28, 0.74),
-                    (0.08, 0.82),
-                    (0.16, 0.62),
-                    (0.0, 0.54),
-                    (0.14, 0.44),
-                    (0.02, 0.28),
-                    (0.22, 0.3),
-                    (0.2, 0.1),
-                    (0.36, 0.22),
-                    (0.4, 0.04),
-                ]
-            };
-            let pts: Vec<(f64, f64)> = pts.iter().map(|(x, y)| (x * w, y * h)).collect();
-            simple(b.poly(&pts).take(), Rect::new(w * 0.25, h * 0.3, w * 0.75, h * 0.7), w, h)
+                    (11462, 4342),
+                    (14790, 0),
+                    (14525, 5777),
+                    (18007, 3172),
+                    (16380, 6532),
+                    (21600, 6645),
+                    (16985, 9402),
+                    (18270, 11290),
+                    (16380, 12310),
+                    (18877, 15632),
+                    (14640, 14350),
+                    (14942, 17370),
+                    (12180, 15935),
+                    (11612, 18842),
+                    (9872, 17370),
+                    (8700, 19712),
+                    (7527, 18125),
+                    (4917, 21600),
+                    (4805, 18240),
+                    (1285, 17825),
+                    (3330, 15370),
+                    (0, 12877),
+                    (3935, 11592),
+                    (1172, 8270),
+                    (5372, 7817),
+                    (4502, 3625),
+                    (8550, 6382),
+                    (9722, 1887),
+                ],
+                w,
+                h,
+            );
+            simple(b.poly(&pts).take(), Rect::new(w * 5372.0 / 21600.0, h * 6382.0 / 21600.0, w * 14640.0 / 21600.0, h * 15935.0 / 21600.0), w, h)
         }
         "ribbon" | "ribbon2" => ribbon(name == "ribbon2", w, h, a(0), a(1)),
         "verticalScroll" | "horizontalScroll" => scroll(name == "verticalScroll", w, h, a(0)),
         "wave" | "doubleWave" => {
-            let amp = h * a(0).clamp(0.0, 20000.0) / 1e5;
-            let shift = w * a(1).clamp(-10000.0, 10000.0) / 1e5;
+            // ECMA-376 wave / doubleWave: the top and bottom edges are cubic waves (one or two
+            // periods) of amplitude adj1, shifted sideways by adj2.
+            let a1 = a(0).clamp(0.0, if name == "wave" { 20000.0 } else { 12500.0 });
+            let a2 = a(1).clamp(-10000.0, 10000.0);
+            let y1 = h * a1 / 100000.0;
+            let dy2 = y1 * 10.0 / 3.0;
+            let (y2, y3, y4) = (y1 - dy2, y1 + dy2, h - y1);
+            let (y5, y6) = (y4 - dy2, y4 + dy2);
+            let of2 = w * a2 / 50000.0;
+            let dx2 = of2.min(0.0);
+            let dxr = of2.max(0.0);
+            let (x2, xr, xl, x10) = (-dx2, w - dxr, dxr, w + dx2);
+            let text_y = h * a1 / 50000.0;
             if name == "wave" {
-                b.m(shift.max(0.0), amp).c(w / 3.0, -amp, 2.0 * w / 3.0, 3.0 * amp, w + shift.min(0.0), amp);
-                b.l(w - shift.max(0.0), h - amp).c(2.0 * w / 3.0, h - 3.0 * amp, w / 3.0, h + amp, -shift.min(0.0), h - amp).z();
+                let dx3 = (dx2 + xr) / 3.0;
+                let (x3, x7) = (x2 + dx3, xl + dx3);
+                let (x4, x8) = ((x3 + xr) / 2.0, (x7 + x10) / 2.0);
+                b.m(x2, y1).c(x3, y2, x4, y3, xr, y1).l(x10, y4).c(x8, y6, x7, y5, xl, y4).z();
             } else {
-                b.m(0.0, amp).c(w / 6.0, -amp, w / 3.0, 3.0 * amp, w / 2.0, amp).c(2.0 * w / 3.0, -amp, 5.0 * w / 6.0, 3.0 * amp, w, amp);
-                b.l(w, h - amp)
-                    .c(5.0 * w / 6.0, h - 3.0 * amp, 2.0 * w / 3.0, h + amp, w / 2.0, h - amp)
-                    .c(w / 3.0, h - 3.0 * amp, w / 6.0, h + amp, 0.0, h - amp)
-                    .z();
+                let (dx3, dx4) = ((dx2 + xr) / 6.0, (dx2 + xr) / 3.0);
+                let (x3, x4, x5) = (x2 + dx3, x2 + dx4, (x2 + xr) / 2.0);
+                let x6 = x5 + dx3;
+                let x7 = (x6 + xr) / 2.0;
+                let (x10b, x11, x12) = (xl + dx3, xl + dx4, (xl + x10) / 2.0);
+                let x13 = x12 + dx3;
+                let x14 = (x13 + x10) / 2.0;
+                b.m(x2, y1).c(x3, y2, x4, y3, x5, y1).c(x6, y2, x7, y3, xr, y1).l(x10, y4);
+                b.c(x14, y6, x13, y5, x12, y4).c(x11, y6, x10b, y5, xl, y4).z();
             }
-            simple(b.take(), Rect::new(0.0, amp * 2.0, w, h - amp * 2.0), w, h)
+            simple(b.take(), Rect::new(x2.max(xl), text_y, xr.min(x10), h - text_y), w, h)
         }
         "wedgeRectCallout" | "wedgeRoundRectCallout" => {
             let r = if name == "wedgeRoundRectCallout" { ss * a(2).clamp(0.0, 50000.0) / 1e5 } else { 0.0 };
@@ -1646,36 +1840,61 @@ fn wedge_rect(w: f64, h: f64, a0: f64, a1: f64, r: f64) -> Geometry {
     g
 }
 
+/// ECMA-376 cloud outline arcs (radii in 43200ths of the box, angles in 60000ths of a degree,
+/// as DrawingML `arcTo` takes them), from the start point (3900, 14370).
+const CLOUD_ARCS: [(f64, f64, f64, f64); 11] = [
+    (6753.0, 9190.0, -11429249.0, 7426832.0),
+    (5333.0, 7267.0, -8646143.0, 5396714.0),
+    (4365.0, 5945.0, -8748475.0, 5983381.0),
+    (4857.0, 6595.0, -7859164.0, 7034504.0),
+    (5333.0, 7273.0, -4722533.0, 6541615.0),
+    (6775.0, 9220.0, -2776035.0, 7816140.0),
+    (5785.0, 7867.0, 37501.0, 6842000.0),
+    (6752.0, 9215.0, 1347096.0, 6910353.0),
+    (7720.0, 10543.0, 3974558.0, 4542661.0),
+    (4360.0, 5918.0, -16496525.0, 8804134.0),
+    (4345.0, 5945.0, -14809710.0, 9151131.0),
+];
+
+/// The cloud's creases: short arcs inside the outline, each from its own start point.
+const CLOUD_CREASES: [(f64, f64, f64, f64, f64, f64); 11] = [
+    (4693.0, 26177.0, 4345.0, 5945.0, 5204520.0, 1585770.0),
+    (6928.0, 34899.0, 4360.0, 5918.0, 4416628.0, 686848.0),
+    (16478.0, 39090.0, 6752.0, 9215.0, 8257449.0, 844866.0),
+    (28827.0, 34751.0, 6752.0, 9215.0, 387196.0, 959901.0),
+    (34129.0, 22954.0, 5785.0, 7867.0, -4217541.0, 4255042.0),
+    (41798.0, 15354.0, 5333.0, 7273.0, 1819082.0, 1665090.0),
+    (38324.0, 5426.0, 4857.0, 6595.0, -824660.0, 891534.0),
+    (29078.0, 3952.0, 4857.0, 6595.0, -8950887.0, 1091722.0),
+    (22141.0, 4720.0, 4365.0, 5945.0, -9809656.0, 1061181.0),
+    (14000.0, 5192.0, 6753.0, 9190.0, -4002417.0, 739161.0),
+    (4127.0, 15789.0, 6753.0, 9190.0, 9459261.0, 711490.0),
+];
+
 fn cloud(name: &str, w: f64, h: f64, a0: f64, a1: f64) -> Geometry {
-    let n = 10;
-    let pts: Vec<Point> = (0..n)
-        .map(|i| {
-            let t = (i as f64 / n as f64 * 360.0 - 90.0).to_radians();
-            let wob = if i % 2 == 0 { 1.0 } else { 0.92 };
-            Point::new(0.5 + 0.40 * wob * t.cos(), 0.5 + 0.36 * wob * t.sin())
-        })
-        .collect();
+    // Drawn in the path's own 43200-unit square, then stretched to the box (as DrawingML lays out
+    // a path with its own w and h), so the arcs keep their shape's proportions at any aspect.
+    let to_box = kurbo::Affine::scale_non_uniform(w / 43200.0, h / 43200.0);
+    let deg = |v: f64| v / 60000.0;
     let mut b = Pb::new();
-    let first = pts.first().copied().unwrap_or(Point::ZERO);
-    b.m(first.x, first.y);
-    for i in 0..n {
-        let p = pts.get(i).copied().unwrap_or(Point::ZERO);
-        let q = pts.get((i + 1) % n).copied().unwrap_or(Point::ZERO);
-        let mid = p.midpoint(q);
-        let out = (mid - Point::new(0.5, 0.5)).normalize();
-        let bulge = (q - p).hypot() * 0.75;
-        let c1 = p + (mid - p) * 0.2 + out * bulge;
-        let c2 = q + (mid - q) * 0.2 + out * bulge;
-        b.c(c1.x, c1.y, c2.x, c2.y, q.x, q.y);
+    b.m(3900.0, 14370.0);
+    for (wr, hr, st, sw) in CLOUD_ARCS {
+        b.arc_spec(wr, hr, deg(st), deg(sw));
     }
     b.z();
-    let mut path = b.take();
-    let bb = path.bounding_box();
-    let sx = if bb.width() > 0.0 { w / bb.width() } else { 1.0 };
-    let sy = if bb.height() > 0.0 { h / bb.height() } else { 1.0 };
-    path.apply_affine(kurbo::Affine::scale_non_uniform(sx, sy) * kurbo::Affine::translate(-bb.origin().to_vec2()));
-    let mut paths = vec![fill(path)];
-    let text_rect = Rect::new(w * 0.2, h * 0.22, w * 0.8, h * 0.78);
+    let mut creases = Pb::new();
+    for (x, y, wr, hr, st, sw) in CLOUD_CREASES {
+        creases.m(x, y).arc_spec(wr, hr, deg(st), deg(sw));
+    }
+    let mut outline = b.take();
+    outline.apply_affine(to_box);
+    let mut paths = vec![fill(outline)];
+    if name == "cloud" {
+        let mut c = creases.take();
+        c.apply_affine(to_box);
+        paths.push(stroke_only(c));
+    }
+    let text_rect = Rect::new(w * 2977.0 / 21600.0, h * 3262.0 / 21600.0, w * 17087.0 / 21600.0, h * 17337.0 / 21600.0);
     let mut handles = vec![];
     if name == "cloudCallout" {
         let tip = Point::new(w / 2.0 + w * a0 / 1e5, h / 2.0 + h * a1 / 1e5);
@@ -1693,71 +1912,119 @@ fn cloud(name: &str, w: f64, h: f64, a0: f64, a1: f64) -> Geometry {
     Geometry { paths, text_rect, handles, sites: mid_sites(w, h) }
 }
 
+/// The equation shapes, by ECMA-376's formulas (checked against PowerPoint's outlines at several
+/// sizes and adjust values). Their bars span 73.49% of the width; the plus and multiply bars are
+/// `adj1` of the shorter side thick, the others' `adj1` of the height.
 fn math(name: &str, w: f64, h: f64, a0: f64, a1: f64, a2: f64) -> Geometry {
+    let pin = |lo: f64, v: f64, hi: f64| v.max(lo).min(hi.max(lo));
     let ss = w.min(h);
-    let t = ss * a0.clamp(0.0, 50000.0) / 1e5;
-    let (cx, cy) = (w / 2.0, h / 2.0);
-    let mx = w * 0.0735;
-    let my = h * 0.0735;
+    let (hc, vc) = (w / 2.0, h / 2.0);
+    let dx1 = w * 73490.0 / 200000.0;
+    let (x1, x2) = (hc - dx1, hc + dx1);
     let mut b = Pb::new();
-    match name {
+    let text = match name {
         "mathPlus" => {
-            let (hx, hy) = (cx - mx, cy - my);
-            b.poly(&[
-                (cx - t / 2.0, cy - hy),
-                (cx + t / 2.0, cy - hy),
-                (cx + t / 2.0, cy - t / 2.0),
-                (cx + hx, cy - t / 2.0),
-                (cx + hx, cy + t / 2.0),
-                (cx + t / 2.0, cy + t / 2.0),
-                (cx + t / 2.0, cy + hy),
-                (cx - t / 2.0, cy + hy),
-                (cx - t / 2.0, cy + t / 2.0),
-                (cx - hx, cy + t / 2.0),
-                (cx - hx, cy - t / 2.0),
-                (cx - t / 2.0, cy - t / 2.0),
-            ]);
+            let a = pin(0.0, a0, 73490.0);
+            let dy1 = h * 73490.0 / 200000.0;
+            let dx2 = ss * a / 200000.0;
+            let (y1, y2, y3, y4) = (vc - dy1, vc - dx2, vc + dx2, vc + dy1);
+            let (xa, xb) = (hc - dx2, hc + dx2);
+            b.poly(&[(x1, y2), (xa, y2), (xa, y1), (xb, y1), (xb, y2), (x2, y2), (x2, y3), (xb, y3), (xb, y4), (xa, y4), (xa, y3), (x1, y3)]);
+            Rect::new(x1, y2, x2, y3)
         }
         "mathMinus" => {
-            b.poly(&[(mx, cy - t / 2.0), (w - mx, cy - t / 2.0), (w - mx, cy + t / 2.0), (mx, cy + t / 2.0)]);
+            let dy1 = h * pin(0.0, a0, 100000.0) / 200000.0;
+            b.poly(&[(x1, vc - dy1), (x2, vc - dy1), (x2, vc + dy1), (x1, vc + dy1)]);
+            Rect::new(x1, vc - dy1, x2, vc + dy1)
         }
         "mathEqual" => {
-            let gap = h * a1.clamp(0.0, 100000.0) / 1e5;
-            b.poly(&[(mx, cy - gap / 2.0 - t), (w - mx, cy - gap / 2.0 - t), (w - mx, cy - gap / 2.0), (mx, cy - gap / 2.0)]);
-            b.poly(&[(mx, cy + gap / 2.0), (w - mx, cy + gap / 2.0), (w - mx, cy + gap / 2.0 + t), (mx, cy + gap / 2.0 + t)]);
+            let a = pin(0.0, a0, 36745.0);
+            let g = pin(0.0, a1, 100000.0 - 2.0 * a);
+            let (dy1, dy2) = (h * a / 100000.0, h * g / 200000.0);
+            let (y2, y3) = (vc - dy2, vc + dy2);
+            let (y1, y4) = (y2 - dy1, y3 + dy1);
+            b.poly(&[(x1, y1), (x2, y1), (x2, y2), (x1, y2)]);
+            b.poly(&[(x1, y3), (x2, y3), (x2, y4), (x1, y4)]);
+            Rect::new(x1, y1, x2, y4)
         }
         "mathNotEqual" => {
-            let gap = h * a2.clamp(0.0, 100000.0) / 1e5;
-            b.poly(&[(mx, cy - gap / 2.0 - t), (w - mx, cy - gap / 2.0 - t), (w - mx, cy - gap / 2.0), (mx, cy - gap / 2.0)]);
-            b.poly(&[(mx, cy + gap / 2.0), (w - mx, cy + gap / 2.0), (w - mx, cy + gap / 2.0 + t), (mx, cy + gap / 2.0 + t)]);
-            let ang = (a1 / 60000.0).to_radians();
-            let dir = Vec2::new(ang.cos(), ang.sin());
-            let len = (h / 2.0 - my) / ang.sin().abs().max(0.2);
-            let perp = Vec2::new(-dir.y, dir.x) * (t / 2.0);
-            let c = Point::new(cx, cy);
-            let p = [c - dir * len - perp, c + dir * len - perp, c + dir * len + perp, c - dir * len + perp];
-            b.poly(&p.map(|q| (q.x, q.y)));
+            let a = pin(0.0, a0, 50000.0);
+            let cr_ang = pin(4200000.0, a1, 6600000.0);
+            let g = pin(0.0, a2, 100000.0 - 2.0 * a);
+            let (dy1, dy2) = (h * a / 100000.0, h * g / 200000.0);
+            let hd2 = (h / 2.0).max(1e-9);
+            let (y2, y3) = (vc - dy2, vc + dy2);
+            let (y1, y4) = (y2 - dy1, y3 + dy1);
+            let cadj2 = cr_ang - 5400000.0;
+            let xadj2 = hd2 * (cadj2 / 60000.0).to_radians().tan();
+            let len = xadj2.hypot(hd2);
+            let bhw = len * dy1 / hd2;
+            let x7 = hc + xadj2 - bhw / 2.0;
+            let at = |y: f64| x7 - xadj2 * y / hd2;
+            let (x6, x5, x4, x3) = (at(y1), at(y2), at(y3), at(y4));
+            let rx7 = x7 + bhw;
+            let dx7 = dy1 * hd2 / len;
+            let dy3 = dy1 * xadj2 / len;
+            let (rx, lx, ry, ly) = if cadj2 > 0.0 { (x7 + dx7, x7, dy3, 0.0) } else { (rx7, rx7 - dx7, 0.0, -dy3) };
+            b.poly(&[
+                (x1, y1),
+                (x6, y1),
+                (lx, ly),
+                (rx, ry),
+                (x6 + bhw, y1),
+                (x2, y1),
+                (x2, y2),
+                (x5 + bhw, y2),
+                (x4 + bhw, y3),
+                (x2, y3),
+                (x2, y4),
+                (x3 + bhw, y4),
+                (w - lx, h - ly),
+                (w - rx, h - ry),
+                (x3, y4),
+                (x1, y4),
+                (x1, y3),
+                (x4, y3),
+                (x5, y2),
+                (x1, y2),
+            ]);
+            Rect::new(x1, y1, x2, y4)
         }
         "mathDivide" => {
-            let gap = h * a1.clamp(0.0, 100000.0) / 1e5;
-            let r = ss * a2.clamp(0.0, 50000.0) / 1e5 / 2.0;
-            b.poly(&[(mx, cy - t / 2.0), (w - mx, cy - t / 2.0), (w - mx, cy + t / 2.0), (mx, cy + t / 2.0)]);
-            b.ellipse(cx, cy - t / 2.0 - gap - r, r, r);
-            b.ellipse(cx, cy + t / 2.0 + gap + r, r, r);
+            let a = pin(1000.0, a0, 36745.0);
+            let max3 = ((73490.0 - a) / 4.0).min(36745.0 * w / h.max(1e-9));
+            let r3 = pin(1000.0, a2, max3);
+            let g = pin(0.0, a1, 73490.0 - 4.0 * r3 - a);
+            let dy1 = h * a / 200000.0;
+            let yg = h * g / 100000.0;
+            let rad = h * r3 / 100000.0;
+            let (y3, y4) = (vc - dy1, vc + dy1);
+            let y2 = y3 - (yg + rad);
+            let y1 = y2 - rad;
+            b.ellipse(hc, y1 + rad, rad, rad);
+            b.ellipse(hc, h - y1 - rad, rad, rad);
+            b.poly(&[(x1, y3), (x2, y3), (x2, y4), (x1, y4)]);
+            Rect::new(x1, y3, x2, y4)
         }
         _ => {
-            // mathMultiply: two bars crossing at the centre along the diagonals.
-            let len = ((cx - mx).powi(2) + (cy - my).powi(2)).sqrt();
-            let c = Point::new(cx, cy);
-            for d in [Vec2::new(cx - mx, cy - my), Vec2::new(cx - mx, -(cy - my))] {
-                let dir = d / d.hypot().max(1e-9);
-                let perp = Vec2::new(-dir.y, dir.x) * (t / 2.0);
-                let p = [c - dir * len - perp, c + dir * len - perp, c + dir * len + perp, c - dir * len + perp];
-                b.poly(&p.map(|q| (q.x, q.y)));
-            }
+            // mathMultiply: an X whose arms run along the box's diagonals.
+            let th = ss * pin(0.0, a0, 51965.0) / 100000.0;
+            let ang = h.atan2(w);
+            let (sa, ca, ta) = (ang.sin(), ang.cos(), ang.tan().max(1e-9));
+            let lm = w.hypot(h) * (1.0 - 51965.0 / 100000.0);
+            let (xm, ym) = (ca * lm / 2.0, sa * lm / 2.0);
+            let (dxam, dyam) = (sa * th / 2.0, ca * th / 2.0);
+            let (xa, ya, xb, yb) = (xm - dxam, ym + dyam, xm + dxam, ym - dyam);
+            let yc = (hc - xb) * ta + yb;
+            let (xd, xe) = (w - xb, w - xa);
+            let xfe = (vc - ya) / ta;
+            let (xf, xl) = (xe - xfe, xa + xfe);
+            let (yg, yh, yi) = (h - ya, h - yb, h - yc);
+            b.poly(&[(xa, ya), (xb, yb), (hc, yc), (xd, yb), (xe, ya), (xf, vc), (xe, yg), (xd, yh), (hc, yi), (xb, yh), (xa, yg), (xl, vc)]);
+            Rect::new(xa, yb, xe, yh)
         }
-    }
-    Geometry { paths: vec![fill(b.take())], text_rect: Rect::new(mx, cy - t / 2.0, w - mx, cy + t / 2.0), handles: vec![], sites: mid_sites(w, h) }
+    };
+    Geometry { paths: vec![fill(b.take())], text_rect: text, handles: vec![], sites: mid_sites(w, h) }
 }
 
 fn ribbon(up: bool, w: f64, h: f64, a0: f64, a1: f64) -> Geometry {
@@ -1968,4 +2235,158 @@ mod tests {
         assert!(build("line", 10.0, 10.0, &[]).unwrap().is_open());
         assert!(!build("rect", 10.0, 10.0, &[]).unwrap().is_open());
     }
+
+    fn on_path(g: &Geometry, p: Point, tol: f64) -> bool {
+        use kurbo::ParamCurveNearest;
+        g.paths.iter().any(|sp| sp.path.segments().any(|seg| seg.nearest(p, 1e-6).distance_sq <= tol * tol))
+    }
+
+    #[test]
+    fn fixed_shapes_follow_the_standards_coordinates() {
+        // Points of ECMA-376's definitions (in 21600ths), checked on a 216 × 108 box.
+        let (w, h) = (216.0, 108.0);
+        let at = |x: f64, y: f64| Point::new(w * x / 21600.0, h * y / 21600.0);
+        let g = build("lightningBolt", w, h, &[]).unwrap();
+        for (x, y) in [(8472.0, 0.0), (16577.0, 12007.0), (21600.0, 21600.0), (0.0, 3890.0)] {
+            assert!(on_path(&g, at(x, y), 1e-6), "lightningBolt ({x}, {y})");
+        }
+        let g = build("irregularSeal1", w, h, &[]).unwrap();
+        assert!(on_path(&g, at(14522.0, 0.0), 1e-6) && on_path(&g, at(8485.0, 21600.0), 1e-6));
+        let g = build("irregularSeal2", w, h, &[]).unwrap();
+        assert!(on_path(&g, at(14790.0, 0.0), 1e-6) && on_path(&g, at(4917.0, 21600.0), 1e-6));
+        // The heart's point is the middle of the bottom edge, its notch a quarter down.
+        let g = build("heart", w, h, &[]).unwrap();
+        assert!(on_path(&g, Point::new(w / 2.0, h), 1e-6) && on_path(&g, Point::new(w / 2.0, h / 4.0), 1e-6));
+        let g = build("flowChartDocument", w, h, &[]).unwrap();
+        assert!(on_path(&g, at(21600.0, 17322.0), 1e-6) && on_path(&g, at(0.0, 20172.0), 1e-6));
+        // Punched tape: the top edge dips to a fifth of the height a quarter of the way along.
+        let g = build("flowChartPunchedTape", w, h, &[]).unwrap();
+        assert!(on_path(&g, Point::new(w / 4.0, h / 5.0), 1e-3) && on_path(&g, Point::new(w * 0.75, 0.0), 1e-3));
+        let g = build("flowChartMultidocument", w, h, &[]).unwrap();
+        assert!(on_path(&g, at(2972.0, 0.0), 1e-6) && on_path(&g, at(18595.0, 18022.0), 1e-6));
+    }
+
+    #[test]
+    fn equation_shapes_match_powerpoints_outlines() {
+        // Corners read off PowerPoint's own outlines of the presets at their default adjusts.
+        let g = build("mathMultiply", 216.0, 216.0, &[]).unwrap();
+        for (x, y) in [(0.32333, 0.15702), (0.5, 0.33369), (0.84298, 0.32333), (0.66631, 0.5), (0.33369, 0.5)] {
+            assert!(on_path(&g, Point::new(216.0 * x, 216.0 * y), 0.01), "multiply ({x}, {y})");
+        }
+        let g = build("mathEqual", 300.0, 120.0, &[]).unwrap();
+        for (x, y) in [(0.13255, 0.5588), (0.86745, 0.794), (0.13255, 0.206), (0.86745, 0.4412)] {
+            assert!(on_path(&g, Point::new(300.0 * x, 120.0 * y), 0.01), "equal ({x}, {y})");
+        }
+        let g = build("mathPlus", 216.0, 216.0, &[]).unwrap();
+        assert!(on_path(&g, Point::new(216.0 * 0.3824, 216.0 * 0.13255), 0.01) && on_path(&g, Point::new(216.0 * 0.86745, 216.0 * 0.6176), 0.01));
+        // A tall "not equal": its slash, leaning at the default 110° from top to bottom, reaches
+        // past the box's sides exactly as far as PowerPoint's (-22.242 to 122.242).
+        let g = build("mathNotEqual", 100.0, 260.0, &[]).unwrap();
+        use kurbo::Shape as _;
+        let bb = g.paths[0].path.bounding_box();
+        assert!((bb.x0 + 22.242).abs() < 0.01 && (bb.x1 - 122.242).abs() < 0.01 && bb.y0.abs() < 1e-6 && (bb.y1 - 260.0).abs() < 1e-6, "{bb:?}");
+    }
+
+    #[test]
+    fn sun_and_waves_match_powerpoints_outlines() {
+        // Points read off PowerPoint's outlines of the presets (216 pt square, default adjusts).
+        let k = 216.0;
+        let g = build("sun", k, k, &[]).unwrap();
+        for (x, y) in [(0.85352, 0.14644), (0.76161, 0.33987), (0.66013, 0.23839), (0.42825, 0.79823), (0.20177, 0.57175), (0.75, 0.5), (0.5, 0.25)] {
+            assert!(on_path(&g, Point::new(k * x, k * y), 0.02), "sun ({x}, {y})");
+        }
+        let g = build("wave", k, k, &[]).unwrap();
+        for (x, y) in [(0.21875, 0.00484), (1.0, 0.125), (1.0, 0.875), (0.0, 0.875)] {
+            assert!(on_path(&g, Point::new(k * x, k * y), 0.05), "wave ({x}, {y})");
+        }
+        // Shifted: a wave of 300 × 120 with adj (20000, 8000) starts 0.16 of the width in.
+        let g = build("wave", 300.0, 120.0, &[20000.0, 8000.0]).unwrap();
+        for (x, y) in [(0.18375, 0.00774), (0.84, 0.2), (1.0, 0.8), (0.16, 0.8)] {
+            assert!(on_path(&g, Point::new(300.0 * x, 120.0 * y), 0.05), "shifted wave ({x}, {y})");
+        }
+    }
+
+    #[test]
+    fn stars_are_stretched_like_the_standards() {
+        // star5 in a 216 pt square: top point at the top middle, side points at 18 degrees on an
+        // ellipse 5.146% wider and 10.557% taller, centred 10.557% below the middle; its bottom
+        // points reach the box's bottom edge.
+        let k = 216.0;
+        let g = build("star5", k, k, &[]).unwrap();
+        let (rx, ry, cy) = (k / 2.0 * 1.05146, k / 2.0 * 1.10557, k / 2.0 * 1.10557);
+        let a = 18f64.to_radians();
+        assert!(on_path(&g, Point::new(k / 2.0, 0.0), 1e-6));
+        assert!(on_path(&g, Point::new(k / 2.0 + rx * a.cos(), cy - ry * a.sin()), 1e-6));
+        use kurbo::Shape as _;
+        let bb = g.paths[0].path.bounding_box();
+        assert!((bb.x0).abs() < 0.5 && (bb.x1 - k).abs() < 0.5 && (bb.y1 - k).abs() < 0.5, "{bb:?}");
+        // star6 is 15.47% wider than its box's half-width allows (its points touch the sides).
+        let g = build("star6", k, k, &[]).unwrap();
+        let bb = g.paths[0].path.bounding_box();
+        assert!((bb.x0).abs() < 0.5 && (bb.x1 - k).abs() < 0.5, "{bb:?}");
+    }
+
+    #[test]
+    fn moon_disk_and_drum_match_powerpoints_outlines() {
+        let k = 216.0;
+        // Moon, default: the inner edge runs through (0.5, 0.5) and (0.625, 0.2266) of the box.
+        let g = build("moon", k, k, &[]).unwrap();
+        for (x, y) in [(0.5, 0.5), (0.626, 0.2266), (0.0, 0.5), (1.0, 0.0)] {
+            assert!(on_path(&g, Point::new(k * x, k * y), 0.5), "moon ({x}, {y})");
+        }
+        // 300 × 120 at 30%: its inner edge reaches 30% of the width in.
+        let g = build("moon", 300.0, 120.0, &[30000.0]).unwrap();
+        assert!(on_path(&g, Point::new(90.0, 60.0), 0.5));
+        // Magnetic disk ends are ellipses h/6 high, drum ends w/6 across.
+        let g = build("flowChartMagneticDisk", k, k, &[]).unwrap();
+        assert!(on_path(&g, Point::new(k, k / 6.0), 0.01) && on_path(&g, Point::new(k / 2.0, k / 3.0), 0.5));
+        let g = build("flowChartMagneticDrum", k, k, &[]).unwrap();
+        assert!(on_path(&g, Point::new(k / 6.0, 0.0), 0.01) && on_path(&g, Point::new(0.0, k / 2.0), 0.01));
+    }
+
+    #[test]
+    fn the_cloud_fills_its_box_at_any_aspect_and_has_creases() {
+        use kurbo::Shape as _;
+        for (w, h) in [(200.0, 200.0), (300.0, 100.0), (60.0, 180.0)] {
+            let g = build("cloud", w, h, &[]).unwrap();
+            let bb = g.paths[0].path.bounding_box();
+            assert!(bb.x0.abs() < w * 0.02 && (bb.x1 - w).abs() < w * 0.02, "{w}×{h}: {bb:?}");
+            assert!(bb.y0.abs() < h * 0.02 && (bb.y1 - h).abs() < h * 0.02, "{w}×{h}: {bb:?}");
+            assert_eq!(g.paths.len(), 2, "outline and creases");
+            assert!(g.paths[1].stroke && g.paths[1].fill == FillMode::None);
+        }
+    }
+
+    #[test]
+    fn spec_arcs_take_angles_as_directions_from_the_centre() {
+        // A DrawingML arc of a 2:1 ellipse from 45° to 90°: 45° is the direction (1, 1) from the
+        // centre, which on that ellipse is the point (r/√5)·(2, 1)… scaled so it lies on it.
+        let mut b = Pb::new();
+        b.m(0.0, 0.0).arc_spec(200.0, 100.0, 45.0, 45.0);
+        let p = b.take();
+        let end = p.elements().last().and_then(|e| match e {
+            kurbo::PathEl::CurveTo(_, _, q) => Some(*q),
+            _ => None,
+        });
+        // Centre: the start sits at direction 45°, i.e. at (k, k) from it with (k/200)² + (k/100)² = 1.
+        let k = 1.0 / (1.0f64 / 40000.0 + 1.0 / 10000.0).sqrt();
+        let c = Point::new(-k, -k);
+        let q = end.unwrap();
+        assert!((q.x - c.x).abs() < 1e-6 && (q.y - (c.y + 100.0)).abs() < 1e-6, "{q:?} vs centre {c:?}");
+    }
+
+    #[test]
+    fn brackets_and_braces_fill_out_to_their_straight_side() {
+        // PowerPoint fills a bracket or brace (when it has a fill) between its curve and the
+        // straight side it opens to; only the curve is outlined.
+        for name in ["leftBracket", "rightBracket", "leftBrace", "rightBrace"] {
+            let g = build(name, 40.0, 100.0, &[]).unwrap();
+            let filled: Vec<_> = g.paths.iter().filter(|p| p.fill != FillMode::None).collect();
+            assert_eq!(filled.len(), 1, "{name}");
+            assert!(!filled[0].stroke, "{name}: the filled area is not outlined");
+            let area = filled[0].path.area().abs();
+            assert!(area > 40.0 * 100.0 * 0.4 && area < 40.0 * 100.0, "{name}: {area}");
+            assert!(g.paths.iter().any(|p| p.stroke && p.fill == FillMode::None), "{name}: the curve is outlined");
+        }
+    }
 }

crates/model/src/anim.rs

@@ -63,7 +63,7 @@ pub static TRANSITIONS: &[(&str, &str, &str, u32, &[&str])] = &[
     ("fracture", "Fracture", "Exciting", 2000, &[]),
     ("crush", "Crush", "Exciting", 2000, &[]),
     ("peelOff", "Peel Off", "Exciting", 1500, &["l", "r"]),
-    ("pageCurlDouble", "Page Curl", "Exciting", 1500, &["l", "r"]),
+    ("pageCurlDouble", "Page Curl", "Exciting", 1500, &["l", "r", "singleL", "singleR"]),
     ("airplane", "Airplane", "Exciting", 2000, &["l", "r"]),
     ("origami", "Origami", "Exciting", 2000, &["l", "r"]),
     ("dissolve", "Dissolve", "Exciting", 1200, &[]),
@@ -72,9 +72,9 @@ pub static TRANSITIONS: &[(&str, &str, &str, u32, &[&str])] = &[
     ("clock", "Clock", "Exciting", 2000, &["clockwise", "counterClockwise", "wedge"]),
     ("ripple", "Ripple", "Exciting", 1400, &["center", "lu", "ru", "ld", "rd"]),
     ("honeycomb", "Honeycomb", "Exciting", 3000, &[]),
-    ("glitter", "Glitter", "Exciting", 2500, &["l", "r", "u", "d"]),
+    ("glitter", "Glitter", "Exciting", 2500, &["l", "r", "u", "d", "hexL", "hexR", "hexU", "hexD"]),
     ("vortex", "Vortex", "Exciting", 3000, &["l", "r", "u", "d"]),
-    ("shred", "Shred", "Exciting", 2000, &["strips", "particles"]),
+    ("shred", "Shred", "Exciting", 2000, &["stripsIn", "stripsOut", "particlesIn", "particlesOut"]),
     ("switch", "Switch", "Exciting", 1250, &["l", "r"]),
     ("flip", "Flip", "Exciting", 1250, &["l", "r"]),
     ("gallery", "Gallery", "Exciting", 1500, &["l", "r"]),
@@ -82,7 +82,7 @@ pub static TRANSITIONS: &[(&str, &str, &str, u32, &[&str])] = &[
     ("doors", "Doors", "Exciting", 1400, &["vert", "horz"]),
     ("box", "Box", "Exciting", 1250, &["l", "r", "u", "d"]),
     ("comb", "Comb", "Exciting", 1000, &["horz", "vert"]),
-    ("zoom", "Zoom", "Exciting", 1000, &["in", "out"]),
+    ("zoom", "Zoom", "Exciting", 1000, &["in", "out", "rotate"]),
     ("random", "Random", "Exciting", 2000, &[]),
     ("pan", "Pan", "Dynamic Content", 1000, &["u", "d", "l", "r"]),
     ("ferris", "Ferris Wheel", "Dynamic Content", 2000, &["l", "r"]),
@@ -93,6 +93,101 @@ pub static TRANSITIONS: &[(&str, &str, &str, u32, &[&str])] = &[
     ("flythrough", "Fly Through", "Dynamic Content", 1000, &["in", "out", "inBounce", "outBounce"]),
 ];
 
+/// The Effect Options label PowerPoint shows for a transition option. Options are stored as the
+/// file format's values: for moving transitions (Push, Wipe, Cover, Pan, Cube…) the direction
+/// things move, so "l" is the effect coming "From Right"; Glitter and the preset effects (Fall
+/// Over, Wind…) name the side itself; Ripple names where the wave heads.
+pub fn transition_option_label(kind: &str, option: &str) -> String {
+    let side = |c: char| match c {
+        'l' => "Left",
+        'r' => "Right",
+        'u' => "Top",
+        _ => "Bottom",
+    };
+    let opposite = |c: char| match c {
+        'l' => 'r',
+        'r' => 'l',
+        'u' => 'd',
+        _ => 'u',
+    };
+    let corner = |o: &str, flip: bool| -> Option<String> {
+        let mut cs = o.chars();
+        let (h, v) = (cs.next()?, cs.next()?);
+        let (h, v) = if flip { (opposite(h), opposite(v)) } else { (h, v) };
+        Some(format!("From {}-{}", side(v), side(h)))
+    };
+    let moving = matches!(
+        kind,
+        "push"
+            | "wipe"
+            | "cover"
+            | "uncover"
+            | "pan"
+            | "vortex"
+            | "cube"
+            | "box"
+            | "rotate"
+            | "orbit"
+            | "gallery"
+            | "conveyor"
+            | "ferris"
+            | "switch"
+            | "flip"
+    );
+    match (kind, option) {
+        (_, "horz") => "Horizontal".into(),
+        (_, "vert") => "Vertical".into(),
+        ("split", o) => format!("{} {}", if o.starts_with("horz") { "Horizontal" } else { "Vertical" }, if o.ends_with("In") { "In" } else { "Out" }),
+        ("fade" | "cut", "throughBlack") => "Through Black".into(),
+        ("fade", _) => "Smoothly".into(),
+        ("cut", _) => "Cut".into(),
+        ("clock", "counterClockwise") => "Counterclockwise".into(),
+        ("clock", "wedge") => "Wedge".into(),
+        ("clock", _) => "Clockwise".into(),
+        ("zoom", "rotate") => "Zoom and Rotate".into(),
+        ("ripple", "center") => "Center".into(),
+        ("ripple", o) => corner(o, true).unwrap_or_else(|| "Center".into()),
+        ("glitter", o) => {
+            let (pat, d) = match o.strip_prefix("hex") {
+                Some(d) => ("Hexagons", d.to_ascii_lowercase()),
+                None => ("Diamonds", o.to_string()),
+            };
+            format!("{pat} From {}", side(d.chars().next().unwrap_or('l')))
+        }
+        ("pageCurlDouble", o) => match o {
+            "singleL" => "Single Left".into(),
+            "singleR" => "Single Right".into(),
+            "r" => "Double Right".into(),
+            _ => "Double Left".into(),
+        },
+        ("shred", o) => {
+            format!("{} {}", if o.starts_with("particles") { "Particles" } else { "Strips" }, if o.ends_with("Out") { "Out" } else { "In" })
+        }
+        ("reveal", o) => format!(
+            "{} {}",
+            if o.starts_with("black") { "Through Black" } else { "Smoothly" },
+            if o.ends_with("Right") { "From Right" } else { "From Left" }
+        ),
+        ("flythrough", o) => {
+            format!("{}{}", if o.starts_with("out") { "Out" } else { "In" }, if o.ends_with("Bounce") { " with Bounce" } else { "" })
+        }
+        ("morph", o) => match o {
+            "words" => "Words".into(),
+            "characters" => "Characters".into(),
+            _ => "Objects".into(),
+        },
+        (_, o) if o.len() == 2 && moving => corner(o, true).unwrap_or_default(),
+        (_, o) if o.len() == 1 && moving => format!("From {}", side(opposite(o.chars().next().unwrap_or('l')))),
+        (_, "l") => "Left".into(),
+        (_, "r") => "Right".into(),
+        (_, "u") => "Top".into(),
+        (_, "d") => "Bottom".into(),
+        (_, "in") => "In".into(),
+        (_, "out") => "Out".into(),
+        (_, o) => o.to_string(),
+    }
+}
+
 #[derive(Clone, Copy, Debug, Default, PartialEq, Eq, Serialize, Deserialize)]
 #[serde(rename_all = "camelCase")]
 pub enum AnimClass {
@@ -291,3 +386,29 @@ pub static ANIMATIONS: &[(&str, &str, AnimClass, u32, u32, &[&str])] = &[
 pub fn animation_info(effect: &str, class: AnimClass) -> Option<&'static (&'static str, &'static str, AnimClass, u32, u32, &'static [&'static str])> {
     ANIMATIONS.iter().find(|a| a.0 == effect && a.2 == class).or_else(|| ANIMATIONS.iter().find(|a| a.0 == effect))
 }
+
+#[cfg(test)]
+mod option_label_tests {
+    use super::*;
+
+    #[test]
+    fn transition_option_labels() {
+        assert_eq!(transition_option_label("push", "l"), "From Right");
+        assert_eq!(transition_option_label("push", "u"), "From Bottom");
+        assert_eq!(transition_option_label("wipe", "r"), "From Left");
+        assert_eq!(transition_option_label("cover", "ru"), "From Bottom-Left");
+        assert_eq!(transition_option_label("ripple", "ru"), "From Bottom-Left");
+        assert_eq!(transition_option_label("glitter", "hexU"), "Hexagons From Top");
+        assert_eq!(transition_option_label("glitter", "l"), "Diamonds From Left");
+        assert_eq!(transition_option_label("wind", "l"), "Left");
+        assert_eq!(transition_option_label("pageCurlDouble", "singleR"), "Single Right");
+        assert_eq!(transition_option_label("shred", "particlesOut"), "Particles Out");
+        assert_eq!(transition_option_label("zoom", "rotate"), "Zoom and Rotate");
+        assert_eq!(transition_option_label("split", "vertIn"), "Vertical In");
+        for (id, _, _, _, opts) in TRANSITIONS {
+            for o in opts.iter() {
+                assert!(!transition_option_label(id, o).is_empty(), "{id}/{o}");
+            }
+        }
+    }
+}

crates/model/src/chart.rs

@@ -134,6 +134,10 @@ pub struct Series {
     /// Combo charts: this series' own type.
     pub kind: Option<ChartType>,
     pub secondary_axis: bool,
+    /// The number format of the series' data labels (Excel code): the labels' own, else the
+    /// source data's.
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub number_format: Option<String>,
 }
 
 #[derive(Clone, Debug, PartialEq, Serialize, Deserialize)]
@@ -144,6 +148,15 @@ pub struct Chart {
     pub categories: Vec<String>,
     pub series: Vec<Series>,
     pub legend: Option<String>,
+    /// `c:legend/c:overlay`: the legend is drawn over the plot instead of shrinking it.
+    pub legend_overlay: bool,
+    /// Text size in points of the axis labels and legend (from their `c:txPr`, else the chart's);
+    /// `None`: the file gives none.
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub text_size: Option<f64>,
+    /// Title text size in points (its rich text or `c:txPr`).
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub title_size: Option<f64>,
     pub data_labels: bool,
     pub gridlines: bool,
     pub axis_titles: (Option<String>, Option<String>),
@@ -159,6 +172,20 @@ pub struct Chart {
     pub vary_colors: bool,
     pub y_min: Option<f64>,
     pub y_max: Option<f64>,
+    /// The value axis' major unit, when the chart fixes it.
+    pub y_major: Option<f64>,
+    /// The value axis' number format (an Excel format code such as `#,##0` or `0.0%`).
+    pub y_format: Option<String>,
+    /// The value axis is deleted (`c:delete`): no labels, though gridlines may stay.
+    pub y_hidden: bool,
+    /// A combo chart's secondary value axis: bounds, major unit and number format.
+    pub y2_min: Option<f64>,
+    pub y2_max: Option<f64>,
+    pub y2_major: Option<f64>,
+    pub y2_format: Option<String>,
+    pub y2_hidden: bool,
+    /// The chart's language (`c:lang`, e.g. `ru-RU`): digit grouping and decimal mark.
+    pub lang: Option<String>,
     /// Original chart XML part kept for round-trip of unmodelled options.
     #[serde(skip_serializing_if = "Option::is_none")]
     pub raw: Option<String>,
@@ -172,6 +199,9 @@ impl Default for Chart {
             categories: vec![],
             series: vec![],
             legend: Some("b".into()),
+            legend_overlay: false,
+            text_size: None,
+            title_size: None,
             data_labels: false,
             gridlines: true,
             axis_titles: (None, None),
@@ -186,6 +216,15 @@ impl Default for Chart {
             vary_colors: false,
             y_min: None,
             y_max: None,
+            y_major: None,
+            y_format: None,
+            y_hidden: false,
+            y2_min: None,
+            y2_max: None,
+            y2_major: None,
+            y2_format: None,
+            y2_hidden: false,
+            lang: None,
             raw: None,
         }
     }
@@ -210,6 +249,81 @@ impl Chart {
         c.vary_colors = n_series == 1;
         c
     }
+    /// A series' own chart type: its own in a combo chart (columns when it names none), else the
+    /// chart's.
+    pub fn series_kind(&self, s: &Series) -> ChartType {
+        match (self.kind, s.kind) {
+            (ChartType::Combo, Some(k)) if k != ChartType::Combo => k,
+            (ChartType::Combo, _) => ChartType::Column,
+            (k, _) => k,
+        }
+    }
+
+    /// Whether a series is plotted against the secondary value axis (combo charts only).
+    pub fn on_secondary(&self, s: &Series) -> bool {
+        self.kind == ChartType::Combo && s.secondary_axis
+    }
+
+    /// The value range of one value axis: the primary axis (`y_min`/`y_max` apply), or a combo
+    /// chart's secondary axis. A combo chart stacks only its stacked series. `None` when no series
+    /// uses that axis.
+    pub fn axis_range(&self, secondary: bool) -> Option<(f64, f64)> {
+        if self.kind != ChartType::Combo {
+            return (!secondary).then(|| self.value_range());
+        }
+        let ser: Vec<&Series> = self.series.iter().filter(|s| self.on_secondary(s) == secondary).collect();
+        if ser.is_empty() {
+            return None;
+        }
+        let (mut lo, mut hi) = (0.0_f64, 0.0_f64);
+        let n = ser.iter().map(|s| s.values.len()).max().unwrap_or(0);
+        let mut percent = false;
+        for i in 0..n {
+            let (mut p, mut m) = (0.0, 0.0);
+            for s in &ser {
+                let k = self.series_kind(s);
+                let Some(v) = s.values.get(i).copied().flatten().filter(|v| v.is_finite()) else { continue };
+                if k.percent() {
+                    percent = true;
+                } else if k.stacked() {
+                    if v >= 0.0 { p += v } else { m += v }
+                } else {
+                    hi = hi.max(v);
+                    lo = lo.min(v);
+                }
+            }
+            hi = hi.max(p);
+            lo = lo.min(m);
+        }
+        if percent {
+            hi = hi.max(1.0);
+        }
+        Some(if secondary { (lo, hi) } else { (self.y_min.unwrap_or(lo), self.y_max.unwrap_or(hi)) })
+    }
+
+    /// A value axis' scale — (min, max, major unit) — with at most `max_intervals` intervals:
+    /// the bounds and unit the chart fixes, else PowerPoint's automatic ones (the data plus 5 %
+    /// headroom, rounded out to a 1-2-5 unit). `None` when no series uses the axis.
+    pub fn axis_scale(&self, secondary: bool, max_intervals: usize) -> Option<(f64, f64, f64)> {
+        let (lo, hi) = self.axis_range(secondary)?;
+        let (fmin, fmax, major) = if secondary { (self.y2_min, self.y2_max, self.y2_major) } else { (self.y_min, self.y_max, self.y_major) };
+        let full_percent = !secondary && self.kind.percent();
+        Some(axis_scale(lo, hi, fmin, fmax, major, max_intervals, !full_percent))
+    }
+
+    /// A value axis label in the axis' number format and the chart's language.
+    pub fn axis_label(&self, secondary: bool, v: f64) -> String {
+        let code = if secondary { &self.y2_format } else { &self.y_format };
+        crate::numfmt::format(code.as_deref().unwrap_or("General"), v, self.lang.as_deref())
+    }
+
+    /// A data label of series `s`: its number format, else its axis', in the chart's language.
+    pub fn data_label(&self, s: &Series, v: f64) -> String {
+        let axis = if self.on_secondary(s) { &self.y2_format } else { &self.y_format };
+        let code = s.number_format.as_ref().or(axis.as_ref());
+        crate::numfmt::format(code.map_or("General", String::as_str), v, self.lang.as_deref())
+    }
+
     /// Value range across series (stacked sums for stacked types).
     pub fn value_range(&self) -> (f64, f64) {
         let mut lo: f64 = 0.0;
@@ -242,6 +356,53 @@ impl Chart {
     }
 }
 
+/// The (min, max, major unit) of an axis over the data range [lo, hi]: `fmin`/`fmax`/`major`
+/// where the chart fixes them; otherwise the range takes in zero, gets 5 % headroom (`headroom`)
+/// and rounds out to the smallest 1-2-5 unit giving at most `max_intervals` intervals.
+pub fn axis_scale(
+    lo: f64,
+    hi: f64,
+    fmin: Option<f64>,
+    fmax: Option<f64>,
+    major: Option<f64>,
+    max_intervals: usize,
+    headroom: bool,
+) -> (f64, f64, f64) {
+    // Values past ±1e100 aren't axis values; clamping keeps the arithmetic finite.
+    let fin = |v: Option<f64>| v.filter(|v| v.is_finite()).map(|v| v.clamp(-1e100, 1e100));
+    let (fmin, fmax) = (fin(fmin), fin(fmax));
+    let (lo, hi) = if lo.is_finite() && hi.is_finite() { (lo.min(hi).clamp(-1e100, 1e100), lo.max(hi).clamp(-1e100, 1e100)) } else { (0.0, 1.0) };
+    let mut lo = fmin.unwrap_or(lo.min(0.0));
+    let mut hi = fmax.unwrap_or(hi.max(lo));
+    if hi - lo < 1e-12 {
+        hi = lo + lo.abs().max(1.0);
+    }
+    let span = hi - lo;
+    if headroom && fmax.is_none() && hi > 0.0 {
+        hi += span * 0.05;
+    }
+    if headroom && fmin.is_none() && lo < 0.0 {
+        lo -= span * 0.05;
+    }
+    let n = max_intervals.clamp(1, 50) as f64;
+    let step = match fin(major).filter(|m| *m > 0.0 && (hi - lo) / m <= 1000.0) {
+        Some(m) => m,
+        None => {
+            let mut step = 10f64.powf(((hi - lo) / n).log10().floor());
+            let mut k = 0;
+            // 1, 2, 5, 10, 20… × the magnitude until the intervals fit.
+            while ((hi / step).ceil() - (lo / step).floor()) > n && k < 30 {
+                step *= if matches!(k % 3, 1) { 2.5 } else { 2.0 };
+                k += 1;
+            }
+            step
+        }
+    };
+    let min = fmin.unwrap_or((lo / step + 1e-9).floor() * step);
+    let max = fmax.unwrap_or((hi / step - 1e-9).ceil() * step).max(min + step);
+    (min, max, step)
+}
+
 /// "Nice" axis scale: (min, max, major step) covering [lo, hi].
 pub fn nice_scale(lo: f64, hi: f64) -> (f64, f64, f64) {
     let (lo, hi) = if lo.is_finite() && hi.is_finite() { (lo.min(hi), lo.max(hi)) } else { (0.0, 1.0) };
@@ -280,6 +441,67 @@ mod tests {
         assert!(b > a);
     }
 
+    #[test]
+    fn automatic_axis_scales_like_powerpoint() {
+        // Weekly spend up to ~715 000 on a plot with room for 9 intervals: 0–800 000 by 100 000.
+        assert_eq!(axis_scale(0.0, 715_000.0, None, None, None, 9, true), (0.0, 800_000.0, 100_000.0));
+        // Clicks up to 6 600: 0–7 000 by 1 000.
+        assert_eq!(axis_scale(0.0, 6_600.0, None, None, None, 9, true), (0.0, 7_000.0, 1_000.0));
+        // Fewer intervals fit on a short axis.
+        assert_eq!(axis_scale(0.0, 6_600.0, None, None, None, 4, true), (0.0, 8_000.0, 2_000.0));
+        // Negative data gets room below; fixed bounds and unit are kept.
+        let (min, max, _) = axis_scale(-30.0, 100.0, None, None, None, 8, true);
+        assert!(min <= -30.0 && max >= 105.0);
+        assert_eq!(axis_scale(0.0, 715_000.0, Some(100_000.0), Some(750_000.0), Some(50_000.0), 9, true), (100_000.0, 750_000.0, 50_000.0));
+        // 100 % stacked stays at 0–1 without headroom.
+        assert_eq!(axis_scale(0.0, 1.0, None, None, None, 5, false), (0.0, 1.0, 0.2));
+        // Nonsense never loops or divides by zero.
+        for (lo, hi) in [(f64::NAN, 1.0), (5.0, 5.0), (0.0, 0.0), (-1e300, 1e300)] {
+            let (a, b, s) = axis_scale(lo, hi, None, None, Some(0.0), 0, true);
+            assert!(a.is_finite() && b.is_finite() && s > 0.0 && b > a, "{lo} {hi}: {a} {b} {s}");
+        }
+    }
+
+    #[test]
+    fn axis_labels_use_the_format_and_language() {
+        let mut c = Chart::sample(ChartType::Column);
+        c.y_format = Some(r#"_-* #\ ##0\ "₽"_-;\-* #\ ##0\ "₽"_-;_-* "-"??\ "₽"_-;_-@_-"#.into());
+        c.lang = Some("ru-RU".into());
+        assert_eq!(c.axis_label(false, 800_000.0), "800\u{a0}000 ₽");
+        assert_eq!(c.axis_label(false, 0.0), "- ₽");
+        // No format: General.
+        assert_eq!(c.axis_label(true, 2.5), "2,5");
+        c.lang = None;
+        assert_eq!(c.axis_label(true, 2.5), "2.5");
+        // Data labels: the series' format, else the axis'.
+        c.lang = Some("ru-RU".into());
+        c.series[0].number_format = Some(r#"#,##0\ "₽""#.into());
+        assert_eq!(c.data_label(&c.series[0], 516_600_000.0), "516\u{a0}600\u{a0}000 ₽");
+        assert_eq!(c.data_label(&c.series[1], 0.0), "- ₽");
+    }
+
+    #[test]
+    fn combo_axis_ranges() {
+        // Spend in columns on the primary axis, clicks as a line on the secondary one.
+        let mut c = Chart::sample(ChartType::Combo);
+        c.series.truncate(2);
+        c.series[0].kind = Some(ChartType::Column);
+        c.series[0].values = vec![Some(200_000.0), Some(310_000.0)];
+        c.series[1].kind = Some(ChartType::Line);
+        c.series[1].values = vec![Some(6_000.0), Some(7_400.0)];
+        c.series[1].secondary_axis = true;
+        assert_eq!(c.axis_range(false), Some((0.0, 310_000.0)));
+        assert_eq!(c.axis_range(true), Some((0.0, 7_400.0)));
+        assert_eq!(c.series_kind(&c.series[1]), ChartType::Line);
+        // Without a secondary series there is no secondary axis; a non-combo chart never has one.
+        c.series[1].secondary_axis = false;
+        assert_eq!(c.axis_range(true), None);
+        let col = Chart::sample(ChartType::Column);
+        assert_eq!(col.axis_range(false), Some(col.value_range()));
+        assert_eq!(col.axis_range(true), None);
+        assert!(!col.on_secondary(&col.series[0]));
+    }
+
     #[test]
     fn sample_ranges() {
         let c = Chart::sample(ChartType::StackedColumn);

crates/model/src/lib.rs

@@ -11,6 +11,7 @@ pub mod anim;
 pub mod chart;
 pub mod defaults;
 pub mod edit;
+pub mod numfmt;
 pub mod resolve;
 pub mod style;
 pub mod table;

crates/model/src/numfmt.rs

@@ -0,0 +1,256 @@
+//! Number formats: Excel format codes (`#,##0`, `0.0%`, `_-* # ##0 "₽"_-;…`, `General`) as chart
+//! axes and data labels show them, in the chart's language (digit grouping and decimal mark).
+
+/// Digit grouping and decimal mark for a language tag (`ru-RU`, `de-DE`, `en-US`).
+fn marks(lang: Option<&str>) -> (char, char) {
+    let l = lang.unwrap_or("en").split(['-', '_']).next().unwrap_or("en").to_ascii_lowercase();
+    match l.as_str() {
+        // Space-grouped, comma decimal.
+        "ru" | "uk" | "be" | "kk" | "fr" | "pl" | "cs" | "sk" | "sv" | "fi" | "nb" | "nn" | "no" | "bg" | "lt" | "lv" | "et" | "hu" | "uz" | "hy"
+        | "ka" | "az" => ('\u{a0}', ','),
+        // Dot-grouped, comma decimal.
+        "de" | "es" | "it" | "pt" | "nl" | "da" | "tr" | "el" | "ro" | "id" | "sr" | "hr" | "sl" | "vi" => ('.', ','),
+        _ => (',', '.'),
+    }
+}
+
+#[derive(Debug, PartialEq)]
+enum Tok {
+    /// Text shown as is.
+    Lit(String),
+    /// A digit placeholder: `0`, `#` or `?`.
+    Digit(char),
+    Dot,
+    Comma,
+    Percent,
+}
+
+/// A section's tokens (`[$₽-419]` gives its symbol; colours, conditions and locales drop out).
+fn tokens(section: &str) -> Vec<Tok> {
+    let mut out = vec![];
+    let mut it = section.chars().peekable();
+    while let Some(c) = it.next() {
+        match c {
+            '"' => {
+                let mut s = String::new();
+                for d in it.by_ref() {
+                    if d == '"' {
+                        break;
+                    }
+                    s.push(d);
+                }
+                out.push(Tok::Lit(s));
+            }
+            '\\' => {
+                if let Some(d) = it.next() {
+                    out.push(Tok::Lit(d.to_string()));
+                }
+            }
+            // Padding the width of the next character: a space.
+            '_' => {
+                it.next();
+                out.push(Tok::Lit(" ".into()));
+            }
+            // Repeat-to-fill: nothing on an axis.
+            '*' => {
+                it.next();
+            }
+            '[' => {
+                let mut s = String::new();
+                for d in it.by_ref() {
+                    if d == ']' {
+                        break;
+                    }
+                    s.push(d);
+                }
+                if let Some(sym) = s.strip_prefix('$') {
+                    let sym = sym.split('-').next().unwrap_or("");
+                    if !sym.is_empty() {
+                        out.push(Tok::Lit(sym.to_string()));
+                    }
+                }
+            }
+            '0' | '#' | '?' => out.push(Tok::Digit(c)),
+            '.' => out.push(Tok::Dot),
+            ',' => out.push(Tok::Comma),
+            '%' => out.push(Tok::Percent),
+            '@' => {}
+            _ => out.push(Tok::Lit(c.to_string())),
+        }
+    }
+    out
+}
+
+/// The format's sections split at `;` (outside quotes, brackets and escapes).
+fn sections(code: &str) -> Vec<&str> {
+    let mut out = vec![];
+    let (mut start, mut quoted, mut bracket, mut escaped) = (0, false, false, false);
+    for (i, c) in code.char_indices() {
+        if escaped {
+            escaped = false;
+            continue;
+        }
+        match c {
+            '\\' if !quoted => escaped = true,
+            '"' => quoted = !quoted,
+            '[' if !quoted => bracket = true,
+            ']' if !quoted => bracket = false,
+            ';' if !quoted && !bracket => {
+                out.push(code.get(start..i).unwrap_or(""));
+                start = i + 1;
+            }
+            _ => {}
+        }
+    }
+    out.push(code.get(start..).unwrap_or(""));
+    out
+}
+
+/// `v` in the General format: up to 10 significant digits, no grouping.
+fn general(v: f64, dec: char) -> String {
+    if v == 0.0 {
+        return "0".into();
+    }
+    let a = v.abs();
+    let s = if !(1e-9..1e11).contains(&a) {
+        format!("{v:.5E}")
+    } else {
+        let digits = (10 - (a.log10().floor() as i32 + 1)).clamp(0, 10) as usize;
+        let s = format!("{v:.digits$}");
+        if s.contains('.') { s.trim_end_matches('0').trim_end_matches('.').to_string() } else { s }
+    };
+    s.replace('.', &dec.to_string())
+}
+
+/// Group an integer's digits in threes with `sep`.
+fn group(digits: &str, sep: char) -> String {
+    let n = digits.chars().count();
+    let mut out = String::new();
+    for (i, d) in digits.chars().enumerate() {
+        if i > 0 && (n - i).is_multiple_of(3) {
+            out.push(sep);
+        }
+        out.push(d);
+    }
+    out
+}
+
+/// `v` formatted with the Excel number format `code` in language `lang` (axis labels: the text
+/// section of a format doesn't apply).
+pub fn format(code: &str, v: f64, lang: Option<&str>) -> String {
+    let (sep, dec) = marks(lang);
+    if !v.is_finite() {
+        return String::new();
+    }
+    let secs = sections(code);
+    // The section for the value's sign; a negative or zero section shows the value unsigned.
+    let (sec, v, minus) = match (secs.as_slice(), v) {
+        ([_, neg, ..], v) if v < 0.0 => (*neg, -v, false),
+        ([_, _, zero, ..], v) if v == 0.0 => (*zero, v, false),
+        ([pos, ..], v) => (*pos, v.abs(), v < 0.0),
+        ([], v) => ("General", v.abs(), v < 0.0),
+    };
+    if sec.trim().eq_ignore_ascii_case("general") || sec.trim().is_empty() {
+        let s = general(v, dec);
+        return if minus { format!("-{s}") } else { s };
+    }
+    let toks = tokens(sec);
+    let first = toks.iter().position(|t| matches!(t, Tok::Digit(_)));
+    let last = toks.iter().rposition(|t| matches!(t, Tok::Digit(_)));
+    let (Some(first), Some(last)) = (first, last) else {
+        // No digits: just the section's text ("-" for zero, a label).
+        let s: String = toks.iter().filter_map(|t| if let Tok::Lit(s) = t { Some(s.as_str()) } else { None }).collect();
+        return s.trim().to_string();
+    };
+    let percent = toks.contains(&Tok::Percent);
+    let number = toks.get(first..=last).unwrap_or(&[]);
+    let dot = number.iter().position(|t| *t == Tok::Dot);
+    let (int_part, frac_part) = match dot {
+        Some(d) => (number.get(..d).unwrap_or(&[]), number.get(d + 1..).unwrap_or(&[])),
+        None => (number, &[][..]),
+    };
+    // Grouping: a comma (or the locale's space, written literally) between integer digits.
+    let grouping = int_part.iter().any(|t| *t == Tok::Comma || matches!(t, Tok::Lit(s) if s.trim().is_empty()));
+    // Commas right after the last digit scale by a thousand each (`#,##0,` = thousands).
+    let after = toks.get(last + 1..).unwrap_or(&[]);
+    let scale_commas = if dot.is_none() { after.iter().take_while(|t| **t == Tok::Comma).count() } else { 0 };
+    let min_int = int_part.iter().filter(|t| **t == Tok::Digit('0')).count();
+    let frac_digits: Vec<char> = frac_part.iter().filter_map(|t| if let Tok::Digit(c) = t { Some(*c) } else { None }).collect();
+    let max_frac = frac_digits.len();
+    let min_frac = frac_digits.iter().filter(|c| **c == '0').count();
+    let mut x = v * if percent { 100.0 } else { 1.0 } / 1000f64.powi(scale_commas as i32);
+    if !x.is_finite() {
+        x = 0.0;
+    }
+    let s = format!("{x:.max_frac$}");
+    let (ip, fp) = s.split_once('.').unwrap_or((s.as_str(), ""));
+    let mut fp = fp.to_string();
+    while fp.len() > min_frac && fp.ends_with('0') {
+        fp.pop();
+    }
+    let ip = ip.trim_start_matches('0');
+    let ip = if ip.len() < min_int { format!("{}{ip}", "0".repeat(min_int - ip.len())) } else { ip.to_string() };
+    let mut num = if grouping { group(&ip, sep) } else { ip };
+    if !fp.is_empty() {
+        num.push(dec);
+        num.push_str(&fp);
+    }
+    let lits = |ts: &[Tok]| -> String {
+        ts.iter()
+            .filter_map(|t| match t {
+                Tok::Lit(s) => Some(s.clone()),
+                Tok::Percent => Some("%".into()),
+                _ => None,
+            })
+            .collect()
+    };
+    let before = lits(toks.get(..first).unwrap_or(&[]));
+    let after = lits(toks.get(last + 1..).unwrap_or(&[]));
+    let out = format!("{before}{num}{after}");
+    let out = out.trim();
+    if minus && !out.is_empty() { format!("-{out}") } else { out.to_string() }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    const RUB: &str = r#"_-* #\ ##0\ "₽"_-;\-* #\ ##0\ "₽"_-;_-* "-"??\ "₽"_-;_-@_-"#;
+
+    #[test]
+    fn russian_accounting_roubles() {
+        assert_eq!(format(RUB, 800_000.0, Some("ru-RU")), "800\u{a0}000 ₽");
+        assert_eq!(format(RUB, 1_234_567.0, Some("ru-RU")), "1\u{a0}234\u{a0}567 ₽");
+        assert_eq!(format(RUB, -5_000.0, Some("ru-RU")), "-5\u{a0}000 ₽");
+        assert_eq!(format(RUB, 0.0, Some("ru-RU")), "- ₽");
+    }
+
+    #[test]
+    fn common_codes() {
+        assert_eq!(format("#,##0", 7000.0, Some("ru-RU")), "7\u{a0}000");
+        assert_eq!(format("#,##0", 7000.0, Some("en-US")), "7,000");
+        assert_eq!(format("#,##0", 7000.0, Some("de-DE")), "7.000");
+        assert_eq!(format("0.0%", 0.125, Some("ru-RU")), "12,5%");
+        assert_eq!(format("0.0%", 0.125, None), "12.5%");
+        assert_eq!(format("0%", 0.0, None), "0%");
+        assert_eq!(format("General", 2.5, Some("ru-RU")), "2,5");
+        assert_eq!(format("General", 400_000.0, Some("ru-RU")), "400000");
+        assert_eq!(format("0.00", 1.23456, None), "1.23");
+        assert_eq!(format("#,##0.0#", 1234.5, None), "1,234.5");
+        assert_eq!(format("#,##0,", 12_345_678.0, None), "12,346");
+        assert_eq!(format("[$₽-419]#,##0", 1500.0, Some("ru-RU")), "₽1\u{a0}500");
+        assert_eq!(format("0;[Red]-0", -3.0, None), "-3");
+        assert_eq!(format("0;0", -3.0, None), "3");
+        assert_eq!(format("0", -3.0, None), "-3");
+        assert_eq!(format("\"x\"0", 5.0, None), "x5");
+    }
+
+    #[test]
+    fn never_panics() {
+        for code in ["", ";", ";;;", "\"", "[", "\\", "0.", ".", "#,", "%", "_", "*", "@", "0E+00", "[$", "\"unterminated"] {
+            for v in [0.0, -1.5, 1e300, f64::NAN, f64::INFINITY, 1e-300] {
+                let _ = format(code, v, Some("ru"));
+            }
+        }
+    }
+}

crates/model/src/style.rs

@@ -92,6 +92,15 @@ pub struct Gradient {
     pub shape: GradientShape,
     #[serde(default = "crate::yes")]
     pub rotate_with_shape: bool,
+    /// `a:tileRect`: the box the gradient is laid out in, as insets from the shape's box
+    /// (fractions; negative reaches outside it). PowerPoint's "from corner" radial presets use it
+    /// to centre the gradient on the corner.
+    #[serde(default, skip_serializing_if = "is_zero4")]
+    pub tile: [f64; 4],
+}
+
+fn is_zero4(v: &[f64; 4]) -> bool {
+    v.iter().all(|x| *x == 0.0)
 }
 
 /// How a picture fills its box: stretched into a (fractional) inset rect, or tiled.
@@ -130,6 +139,10 @@ pub struct PictureFill {
     /// 0–1 opacity of the picture.
     pub alpha: Option<f64>,
     pub adjust: PictureAdjust,
+    /// `rotWithShape="0"`: the picture keeps to the slide's axes when its shape is rotated or
+    /// flipped.
+    #[serde(skip_serializing_if = "std::ops::Not::not")]
+    pub upright: bool,
 }
 
 /// Picture corrections and colour (Picture Format ▸ Corrections / Color / Transparency).
@@ -148,6 +161,12 @@ pub struct PictureAdjust {
     /// Make a colour transparent (Set Transparent Color).
     pub clear_color: Option<Rgba>,
     pub sharpen: f64,
+    /// `a:biLevel`: black and white, split at this luminance (0–1).
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub bilevel: Option<f64>,
+    /// `a:alphaInv`: opacity inverted.
+    #[serde(skip_serializing_if = "std::ops::Not::not")]
+    pub alpha_inv: bool,
 }
 
 #[derive(Clone, Debug, PartialEq, Serialize, Deserialize)]
@@ -387,6 +406,16 @@ pub struct Effects {
     pub bevel: Option<String>,
     /// Unmodelled 3-D XML kept for round-trip (`scene3d`, `sp3d`).
     pub raw3d: Option<String>,
+    /// `a:fillOverlay`: a fill blended over the shape's fill (`blend`: `over`, `mult`, `screen`,
+    /// `darken`, `lighten`). Only solid and gradient overlays are kept.
+    pub fill_overlay: Option<FillOverlay>,
+}
+
+#[derive(Clone, Debug, PartialEq, Serialize, Deserialize)]
+#[serde(rename_all = "camelCase")]
+pub struct FillOverlay {
+    pub blend: String,
+    pub fill: Fill,
 }
 
 impl Effects {
@@ -397,6 +426,7 @@ impl Effects {
             && self.soft_edge.is_none()
             && self.reflection.is_none()
             && self.bevel.is_none()
+            && self.fill_overlay.is_none()
     }
 }
 

crates/model/src/tests.rs

@@ -69,7 +69,8 @@ fn a_gradient_without_stops_takes_them_from_its_style() {
     let p = Presentation::default();
     let s = &p.slides[0];
     let ctx = Ctx::for_slide(&p, s).unwrap();
-    let own = style::Gradient { stops: vec![], shape: style::GradientShape::Linear { angle: 45.0, scaled: true }, rotate_with_shape: true };
+    let own =
+        style::Gradient { tile: [0.0; 4], stops: vec![], shape: style::GradientShape::Linear { angle: 45.0, scaled: true }, rotate_with_shape: true };
     let mut st = ShapeStyle::accent(SchemeSlot::Accent2);
     st.fill_ref.0 = 3;
     let sh = Shape { style: Some(st.clone()), fill: Some(Fill::Gradient(own.clone())), ..Default::default() };

crates/model/src/text.rs

@@ -55,6 +55,10 @@ pub enum TextDir {
     Vertical270,
     Stacked,
     EaVertical,
+    /// `mongolianVert`: turned like `vert`, lines running from left to right.
+    MongolianVertical,
+    /// `wordArtVertRtl`: stacked, lines running from right to left.
+    StackedRtl,
 }
 
 impl TextDir {
@@ -65,14 +69,18 @@ impl TextDir {
             TextDir::Vertical270 => "vert270",
             TextDir::Stacked => "wordArtVert",
             TextDir::EaVertical => "eaVert",
+            TextDir::MongolianVertical => "mongolianVert",
+            TextDir::StackedRtl => "wordArtVertRtl",
         }
     }
     pub fn from_xml(s: &str) -> Option<Self> {
         Some(match s {
             "horz" => TextDir::Horizontal,
-            "vert" | "mongolianVert" => TextDir::Vertical,
+            "vert" => TextDir::Vertical,
+            "mongolianVert" => TextDir::MongolianVertical,
             "vert270" => TextDir::Vertical270,
-            "wordArtVert" | "wordArtVertRtl" => TextDir::Stacked,
+            "wordArtVert" => TextDir::Stacked,
+            "wordArtVertRtl" => TextDir::StackedRtl,
             "eaVert" => TextDir::EaVertical,
             _ => return None,
         })

crates/model/src/theme.rs

@@ -108,6 +108,7 @@ fn ph() -> ColorRef {
 pub fn default_format() -> FormatScheme {
     let grad = |a: i32, b: i32| {
         Fill::Gradient(Gradient {
+            tile: [0.0; 4],
             stops: vec![
                 GradientStop { pos: 0.0, color: ph().with(ColorTransform::LumMod(a)).with(ColorTransform::SatMod(103000)) },
                 GradientStop { pos: 1.0, color: ph().with(ColorTransform::LumMod(b)) },

crates/pptx/src/maps.rs

@@ -17,7 +17,12 @@ pub fn transition_from_xml(e: &El) -> Option<(String, String)> {
     Some((k, if has_opts { o } else { String::new() }))
 }
 
+/// Preset transitions (`p15:prstTrans`) whose "Left" option PowerPoint writes with `invX="1"`
+/// (the others write it for "Right"), as observed on PowerPoint's own files.
+const INVX_LEFT: &[&str] = &["wind", "airplane", "origami"];
+
 fn transition_from_xml_raw(e: &El) -> Option<(String, String)> {
+    // Defaults are what PowerPoint leaves out: e.g. it writes Push Left as `<p:push/>`.
     let dir = |d: &str| e.attr("dir").unwrap_or(d).to_string();
     let k = |s: &str| s.to_string();
     Some(match e.local() {
@@ -25,16 +30,22 @@ fn transition_from_xml_raw(e: &El) -> Option<(String, String)> {
         "cut" => (k("cut"), if e.bool("thruBlk") == Some(true) { k("throughBlack") } else { String::new() }),
         "push" => (k("push"), dir("l")),
         "wipe" => (k("wipe"), dir("l")),
+        // Diagonal wipes.
+        "strips" => (k("wipe"), dir("lu")),
         "split" => {
             let o = e.attr("orient").unwrap_or("horz");
             let d = e.attr("dir").unwrap_or("out");
             (k("split"), format!("{o}{}", if d == "in" { "In" } else { "Out" }))
         }
-        "randomBar" => (k("randomBar"), dir("vert")),
+        "randomBar" => (k("randomBar"), dir("horz")),
         "circle" => (k("shape"), k("circle")),
         "diamond" => (k("shape"), k("diamond")),
         "plus" => (k("shape"), k("plus")),
-        "zoom" => (k("zoom"), dir("in")),
+        // Shape In / Out (the slide zooming in a box).
+        "zoom" => (k("shape"), if e.attr("dir") == Some("in") { k("in") } else { k("out") }),
+        // The Zoom transition, and its Zoom and Rotate option.
+        "warp" => (k("zoom"), if e.attr("dir") == Some("in") { k("in") } else { k("out") }),
+        "newsflash" => (k("zoom"), k("rotate")),
         "pull" => (k("uncover"), dir("l")),
         "cover" => (k("cover"), dir("l")),
         "checker" => (k("checker"), dir("horz")),
@@ -47,14 +58,22 @@ fn transition_from_xml_raw(e: &El) -> Option<(String, String)> {
         "switch" => (k("switch"), dir("r")),
         "flip" => (k("flip"), dir("r")),
         "ripple" => (k("ripple"), dir("center")),
-        "doors" => (k("doors"), dir("vert")),
-        "window" => (k("window"), dir("vert")),
+        "doors" => (k("doors"), dir("horz")),
+        "window" => (k("window"), dir("horz")),
         "ferris" => (k("ferris"), dir("l")),
         "gallery" => (k("gallery"), dir("l")),
         "conveyor" => (k("conveyor"), dir("l")),
-        "pan" => (k("pan"), dir("d")),
-        "glitter" => (k("glitter"), dir("l")),
-        "shred" => (k("shred"), if e.attr("pattern") == Some("crush") { k("particles") } else { k("strips") }),
+        "pan" => (k("pan"), dir("l")),
+        "glitter" => {
+            let d = dir("l");
+            if e.attr("pattern") == Some("hexagon") { (k("glitter"), format!("hex{}", d.to_ascii_uppercase())) } else { (k("glitter"), d) }
+        }
+        "shred" => {
+            // `crush` is what DeckCraft wrote before it knew PowerPoint's `rectangle`.
+            let particles = matches!(e.attr("pattern"), Some("rectangle" | "crush"));
+            let out = e.attr("dir") == Some("out");
+            (k("shred"), format!("{}{}", if particles { "particles" } else { "strips" }, if out { "Out" } else { "In" }))
+        }
         "reveal" => {
             let black = e.bool("thruBlk") == Some(true);
             let right = e.attr("dir") == Some("r");
@@ -78,11 +97,16 @@ fn transition_from_xml_raw(e: &El) -> Option<(String, String)> {
         }
         "prstTrans" => {
             let prst = e.attr("prst").unwrap_or("fallOver");
+            let inv = e.bool("invX") == Some(true);
+            if prst == "pageCurlSingle" {
+                return Some((k("pageCurlDouble"), if inv { k("singleR") } else { k("singleL") }));
+            }
             let known = deckcraft_model::anim::TRANSITIONS.iter().any(|t| t.0 == prst);
             if !known {
                 return None;
             }
-            (k(prst), if e.bool("invX") == Some(true) { k("r") } else { k("l") })
+            let left = if INVX_LEFT.contains(&prst) { inv } else { !inv };
+            (k(prst), if left { k("l") } else { k("r") })
         }
         "morph" => (
             k("morph"),
@@ -119,7 +143,10 @@ pub fn transition_to_xml(w: &mut W, kind: &str, option: &str) -> Option<&'static
         "fade" => w.empty("p:fade", A::new().t("thruBlk", option == "throughBlack")),
         "cut" => w.empty("p:cut", A::new().t("thruBlk", option == "throughBlack")),
         "push" => w.empty("p:push", A::new().a("dir", lrud("u"))),
-        "wipe" => w.empty("p:wipe", A::new().a("dir", lrud("r"))),
+        "wipe" => match option {
+            "lu" | "ru" | "ld" | "rd" => w.empty("p:strips", A::new().a("dir", option)),
+            _ => w.empty("p:wipe", A::new().a("dir", lrud("r"))),
+        },
         "split" => {
             let (o, d) = match option {
                 "vertIn" => ("vert", "in"),
@@ -136,7 +163,13 @@ pub fn transition_to_xml(w: &mut W, kind: &str, option: &str) -> Option<&'static
             "in" | "out" => w.empty("p:zoom", A::new().a("dir", option)),
             _ => w.empty0("p:circle"),
         },
-        "zoom" => w.empty("p:zoom", A::new().a("dir", if option == "out" { "out" } else { "in" })),
+        "zoom" => match option {
+            "rotate" => w.empty0("p:newsflash"),
+            _ => {
+                w.empty("p14:warp", A::new().a("dir", if option == "out" { "out" } else { "in" }));
+                return Some("p14");
+            }
+        },
         "uncover" => w.empty("p:pull", A::new().a("dir", eight("l"))),
         "cover" => w.empty("p:cover", A::new().a("dir", eight("l"))),
         "checker" => w.empty("p:checker", A::new().a("dir", hv("horz"))),
@@ -160,9 +193,15 @@ pub fn transition_to_xml(w: &mut W, kind: &str, option: &str) -> Option<&'static
             w.empty0("p14:flash");
             return Some("p14");
         }
-        "vortex" | "glitter" => {
-            let name = if kind == "vortex" { "p14:vortex" } else { "p14:glitter" };
-            w.empty(name, A::new().a("dir", lrud("l")));
+        "vortex" => {
+            w.empty("p14:vortex", A::new().a("dir", lrud("l")));
+            return Some("p14");
+        }
+        "glitter" => {
+            let hex = option.starts_with("hex");
+            let d = option.trim_start_matches("hex").to_ascii_lowercase();
+            let d = if matches!(d.as_str(), "l" | "r" | "u" | "d") { d } else { "l".to_string() };
+            w.empty("p14:glitter", A::new().a("dir", d).o("pattern", hex.then_some("hexagon")));
             return Some("p14");
         }
         "switch" | "flip" | "gallery" | "conveyor" | "ferris" => {
@@ -194,7 +233,11 @@ pub fn transition_to_xml(w: &mut W, kind: &str, option: &str) -> Option<&'static
             return Some("p14");
         }
         "shred" => {
-            w.empty("p14:shred", A::new().a("pattern", if option == "particles" { "crush" } else { "strip" }));
+            let particles = option.starts_with("particles");
+            w.empty(
+                "p14:shred",
+                A::new().a("pattern", if particles { "rectangle" } else { "strip" }).a("dir", if option.ends_with("Out") { "out" } else { "in" }),
+            );
             return Some("p14");
         }
         "reveal" => {
@@ -215,8 +258,13 @@ pub fn transition_to_xml(w: &mut W, kind: &str, option: &str) -> Option<&'static
             );
             return Some("p14");
         }
+        "pageCurlDouble" if option.starts_with("single") => {
+            w.empty("p15:prstTrans", A::new().a("prst", "pageCurlSingle").t("invX", option == "singleR"));
+            return Some("p15");
+        }
         "fallOver" | "drape" | "curtains" | "wind" | "prestige" | "fracture" | "crush" | "peelOff" | "pageCurlDouble" | "airplane" | "origami" => {
-            w.empty("p15:prstTrans", A::new().a("prst", kind).t("invX", option == "r"));
+            let inv = if INVX_LEFT.contains(&kind) { option == "l" } else { option == "r" };
+            w.empty("p15:prstTrans", A::new().a("prst", kind).t("invX", inv));
             return Some("p15");
         }
         "morph" => {
@@ -342,16 +390,7 @@ mod tests {
                 assert!(!ns.is_empty());
                 let d = parse(w.s.as_bytes()).unwrap();
                 let (k, opt) = transition_from_xml(&d.root).unwrap_or_else(|| panic!("no read for {kind}"));
-                // `shape` in/out are written as zoom; everything else must come back.
-                if *kind == "shape" && (o == "in" || o == "out") {
-                    assert_eq!(k, "zoom");
-                    continue;
-                }
                 assert_eq!(k, *kind, "kind for {kind}/{o}");
-                // PresentationML wipes have no diagonal directions.
-                if *kind == "wipe" && o.len() == 2 {
-                    continue;
-                }
                 if !o.is_empty() {
                     assert_eq!(opt, o, "option for {kind}");
                 }

crates/pptx/src/read/chart.rs

@@ -97,10 +97,30 @@ pub(crate) fn chart_from(root: &El) -> Option<Chart> {
         c.title = None;
     }
     c.legend = ch.child("legend").map(|l| l.child_val("legendPos").unwrap_or("r").to_string());
+    c.legend_overlay = ch.child("legend").and_then(|l| l.child("overlay")).and_then(|o| o.bool("val")).unwrap_or(false);
     c.chart_fill = simple_fill(root.child("spPr"));
     c.plot_fill = simple_fill(pa.child("spPr"));
 
     let mut kinds: Vec<ChartType> = vec![];
+    // The value axis the first plot group uses is the primary one; a group on another value axis
+    // (a combo chart's line on the right) is on the secondary axis.
+    let val_ids: Vec<(&str, bool)> =
+        pa.children_named("valAx").filter_map(|a| Some((a.child_val("axId")?, matches!(a.child_val("axPos"), Some("l" | "r"))))).collect();
+    // A group's value axis: its vertical one when it has two (scatter), else its one.
+    let group_val_axis = |g: &El| {
+        let ids: Vec<(&str, bool)> =
+            g.children_named("axId").filter_map(|a| a.attr("val")).filter_map(|id| val_ids.iter().find(|(v, _)| *v == id).copied()).collect();
+        ids.iter().find(|(_, vertical)| *vertical).or(ids.first()).map(|(id, _)| id.to_string())
+    };
+    // The primary value axis is the one on the left (bottom for bar charts); the secondary one
+    // sits on the right or top, or crosses the category axis at its maximum.
+    let secondary_placed = |a: &El| a.child_val("crosses") == Some("max") || matches!(a.child_val("axPos"), Some("r" | "t"));
+    let used: Vec<String> = pa.elements().filter(|g| g.local().ends_with("Chart")).filter_map(group_val_axis).collect();
+    let primary_val: Option<String> = used
+        .iter()
+        .find(|id| pa.children_named("valAx").find(|a| a.child_val("axId") == Some(id.as_str())).is_some_and(|a| !secondary_placed(a)))
+        .or(used.first())
+        .cloned();
     for g in pa.elements() {
         let name = g.local();
         if !name.ends_with("Chart") {
@@ -166,6 +186,8 @@ pub(crate) fn chart_from(root: &El) -> Option<Chart> {
             c.data_labels = true;
         }
         kinds.push(kind);
+        let val_axis = group_val_axis(g);
+        let secondary = val_axis.is_some() && val_axis != primary_val;
         for s in g.children_named("ser").take(1000) {
             let mut ser = Series {
                 name: s.child("tx").map(strings).and_then(|v| v.into_iter().next()).unwrap_or_default(),
@@ -174,11 +196,22 @@ pub(crate) fn chart_from(root: &El) -> Option<Chart> {
                 smooth: s.child("smooth").and_then(|v| v.bool("val")).unwrap_or(false),
                 marker: s.path(&["marker", "symbol"]).and_then(|m| m.attr("val")).filter(|m| *m != "none").map(String::from),
                 kind: Some(kind),
+                secondary_axis: secondary,
                 ..Default::default()
             };
             if let Some(d) = s.child("dLbls").and_then(|d| d.child("showVal")).and_then(|v| v.bool("val")) {
                 ser.data_labels = Some(d);
             }
+            // Data labels' number format: the series' labels', the group's, else the source data's.
+            let label_fmt = |d: Option<&El>| {
+                d.and_then(|d| d.child("numFmt"))
+                    .filter(|n| n.attr("sourceLinked") != Some("1"))
+                    .and_then(|n| n.attr("formatCode"))
+                    .map(str::to_string)
+            };
+            let source =
+                s.child("val").or_else(|| s.child("yVal")).and_then(|v| v.find("numCache")).and_then(|c| c.child("formatCode")).map(|f| f.text());
+            ser.number_format = label_fmt(s.child("dLbls")).or_else(|| label_fmt(g.child("dLbls"))).or(source).filter(|f| !f.is_empty());
             for dp in s.children_named("dPt") {
                 if let (Some(i), Some(f)) = (dp.child("idx").and_then(|i| i.u32("val")), simple_fill(dp.child("spPr"))) {
                     ser.point_fills.push((i as usize, f));
@@ -207,11 +240,29 @@ pub(crate) fn chart_from(root: &El) -> Option<Chart> {
     if c.kind != ChartType::Combo {
         for s in &mut c.series {
             s.kind = None;
+            s.secondary_axis = false;
         }
     }
     // Axes.
+    c.lang = root.child_val("lang").map(str::to_string);
     let vertical = |a: &&El| matches!(a.child_val("axPos"), Some("l" | "r"));
-    let val_ax = pa.children_named("valAx").find(vertical).or_else(|| pa.children_named("valAx").last());
+    let by_id = |id: &Option<String>| pa.children_named("valAx").find(|a| id.is_some() && a.child_val("axId") == id.as_deref());
+    let val_ax = by_id(&primary_val).or_else(|| pa.children_named("valAx").find(vertical)).or_else(|| pa.children_named("valAx").last());
+    let num = |a: &El, k: &str| a.child_val(k).and_then(|v| v.parse::<f64>().ok()).filter(|v| v.is_finite());
+    let format_code = |a: &El| a.child("numFmt").and_then(|n| n.attr("formatCode")).map(str::to_string);
+    let deleted = |a: &El| a.child("delete").and_then(|d| d.bool("val")) == Some(true);
+    if c.kind == ChartType::Combo && c.series.iter().any(|s| s.secondary_axis) {
+        let primary_id = val_ax.and_then(|a| a.child_val("axId"));
+        // The other vertical value axis is the secondary one.
+        if let Some(a) = pa.children_named("valAx").find(|a| a.child_val("axId") != primary_id && vertical(a)) {
+            let sc = a.child("scaling");
+            c.y2_min = sc.and_then(|s| num(s, "min"));
+            c.y2_max = sc.and_then(|s| num(s, "max"));
+            c.y2_major = num(a, "majorUnit");
+            c.y2_format = format_code(a);
+            c.y2_hidden = deleted(a);
+        }
+    }
     let cat_ax = pa.child("catAx").or_else(|| pa.child("dateAx")).or_else(|| pa.children_named("valAx").find(|a| !vertical(a)));
     if let Some(v) = val_ax {
         c.gridlines = v.child("majorGridlines").is_some();
@@ -219,9 +270,122 @@ pub(crate) fn chart_from(root: &El) -> Option<Chart> {
         c.y_min = sc.and_then(|s| s.child_val("min")).and_then(|v| v.parse().ok()).filter(|v: &f64| v.is_finite());
         c.y_max = sc.and_then(|s| s.child_val("max")).and_then(|v| v.parse().ok()).filter(|v: &f64| v.is_finite());
         c.axis_titles.1 = v.child("title").map(|t| rich_text(t).unwrap_or_else(|| "Axis Title".into()));
+        c.y_major = num(v, "majorUnit");
+        c.y_format = format_code(v);
+        c.y_hidden = deleted(v);
     }
     if let Some(a) = cat_ax {
         c.axis_titles.0 = a.child("title").map(|t| rich_text(t).unwrap_or_else(|| "Axis Title".into()));
     }
+    // Text sizes as the file sets them (PowerPoint draws chart text at these sizes, not scaled to
+    // the chart): the axes' and legend's, else the whole chart's; the title's own.
+    let chart_size = text_size(root.child("txPr"));
+    c.text_size = [val_ax, cat_ax, ch.child("legend")].into_iter().flatten().find_map(|e| text_size(e.child("txPr"))).or(chart_size);
+    c.title_size = ch.child("title").and_then(|t| text_size(t.child("tx").and_then(|x| x.child("rich"))).or_else(|| text_size(t.child("txPr"))));
     Some(c)
 }
+
+/// The size in points of the first `a:defRPr` or `a:rPr` with one under `e` (`sz` in hundredths).
+fn text_size(e: Option<&El>) -> Option<f64> {
+    fn rec(e: &El, depth: usize) -> Option<f64> {
+        if depth > 8 {
+            return None;
+        }
+        for c in e.elements() {
+            if (c.is("defRPr") || c.is("rPr"))
+                && let Some(v) = c.attr("sz").and_then(|v| v.parse::<f64>().ok()).filter(|v| v.is_finite() && *v > 0.0)
+            {
+                return Some((v / 100.0).clamp(1.0, 400.0));
+            }
+            if let Some(v) = rec(c, depth + 1) {
+                return Some(v);
+            }
+        }
+        None
+    }
+    rec(e?, 0)
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn legend_position_and_overlay_are_read() {
+        let legend = r#"<c:legend><c:legendPos val="r"/><c:overlay val="1"/></c:legend>"#;
+        let xml = format!(
+            r#"<c:chartSpace xmlns:c="http://schemas.openxmlformats.org/drawingml/2006/chart"><c:chart><c:plotArea><c:barChart><c:barDir val="col"/></c:barChart></c:plotArea>{legend}</c:chart></c:chartSpace>"#
+        );
+        let c = read_chart_xml(xml.as_bytes()).unwrap();
+        assert_eq!(c.legend.as_deref(), Some("r"));
+        assert!(c.legend_overlay);
+        let xml = br#"<c:chartSpace xmlns:c="http://schemas.openxmlformats.org/drawingml/2006/chart"><c:chart><c:plotArea><c:barChart><c:barDir val="col"/></c:barChart></c:plotArea><c:legend/></c:chart></c:chartSpace>"#;
+        let c = read_chart_xml(xml).unwrap();
+        assert_eq!(c.legend.as_deref(), Some("r"));
+        assert!(!c.legend_overlay);
+    }
+
+    #[test]
+    fn combo_chart_with_a_secondary_axis() {
+        // Columns on axes 1/2, a line on axes 3/4 whose value axis is on the right.
+        let xml = br##"<c:chartSpace xmlns:c="http://schemas.openxmlformats.org/drawingml/2006/chart" xmlns:a="http://schemas.openxmlformats.org/drawingml/2006/main"><c:lang val="ru-RU"/><c:chart><c:plotArea>
+<c:barChart><c:barDir val="col"/><c:grouping val="clustered"/><c:ser><c:idx val="0"/><c:tx><c:v>Spend</c:v></c:tx><c:cat><c:strLit><c:ptCount val="2"/><c:pt idx="0"><c:v>W1</c:v></c:pt><c:pt idx="1"><c:v>W2</c:v></c:pt></c:strLit></c:cat><c:val><c:numLit><c:ptCount val="2"/><c:pt idx="0"><c:v>200000</c:v></c:pt><c:pt idx="1"><c:v>310000</c:v></c:pt></c:numLit></c:val></c:ser><c:axId val="1"/><c:axId val="2"/></c:barChart>
+<c:lineChart><c:grouping val="standard"/><c:ser><c:idx val="1"/><c:tx><c:v>Clicks</c:v></c:tx><c:spPr><a:ln w="28575"><a:solidFill><a:srgbClr val="00B050"/></a:solidFill></a:ln></c:spPr><c:val><c:numLit><c:ptCount val="2"/><c:pt idx="0"><c:v>6000</c:v></c:pt><c:pt idx="1"><c:v>7400</c:v></c:pt></c:numLit></c:val></c:ser><c:marker val="1"/><c:axId val="3"/><c:axId val="4"/></c:lineChart>
+<c:catAx><c:axId val="1"/><c:axPos val="b"/><c:crossAx val="2"/></c:catAx><c:valAx><c:axId val="2"/><c:axPos val="l"/><c:numFmt formatCode="#,##0" sourceLinked="1"/><c:crossAx val="1"/><c:majorUnit val="100000"/></c:valAx>
+<c:valAx><c:axId val="4"/><c:scaling><c:max val="8000"/></c:scaling><c:axPos val="r"/><c:numFmt formatCode="0.0" sourceLinked="0"/><c:crossAx val="3"/></c:valAx><c:catAx><c:axId val="3"/><c:delete val="1"/><c:axPos val="b"/><c:crossAx val="4"/></c:catAx>
+</c:plotArea></c:chart></c:chartSpace>"##;
+        let c = read_chart_xml(xml).unwrap();
+        assert_eq!(c.kind, ChartType::Combo);
+        assert_eq!(c.series.len(), 2);
+        assert!(!c.series[0].secondary_axis);
+        assert!(c.series[1].secondary_axis);
+        assert_eq!(c.series[1].kind, Some(ChartType::LineMarkers));
+        assert!(c.series[1].line.as_ref().is_some_and(|l| l.width.is_some_and(|w| (w - 2.25).abs() < 0.01)));
+        // Each value axis' number format, bounds and unit; the chart's language.
+        assert_eq!(c.y_format.as_deref(), Some("#,##0"));
+        assert_eq!((c.y_major, c.y2_max, c.y2_format.as_deref()), (Some(100000.0), Some(8000.0), Some("0.0")));
+        assert_eq!(c.lang.as_deref(), Some("ru-RU"));
+        // Group order doesn't decide: columns on the right-hand axis are the secondary series even
+        // when their group comes first, and the line on the left is primary.
+        let swapped = String::from_utf8_lossy(xml)
+            .replace(
+                "<c:axPos val=\"l\"/><c:numFmt formatCode=\"#,##0\"",
+                "<c:axPos val=\"r\"/><c:crosses val=\"max\"/><c:numFmt formatCode=\"#,##0\"",
+            )
+            .replace("<c:axPos val=\"r\"/><c:numFmt formatCode=\"0.0\"", "<c:axPos val=\"l\"/><c:numFmt formatCode=\"0.0\"");
+        let c2 = read_chart_xml(swapped.as_bytes()).unwrap();
+        assert!(c2.series[0].secondary_axis && !c2.series[1].secondary_axis);
+        assert_eq!((c2.y_format.as_deref(), c2.y2_format.as_deref()), (Some("0.0"), Some("#,##0")));
+        // A chart of one type on one axis has no secondary series.
+        let single = String::from_utf8_lossy(xml)
+            .replace("<c:axId val=\"3\"/><c:axId val=\"4\"/></c:lineChart>", "<c:axId val=\"1\"/><c:axId val=\"2\"/></c:lineChart>");
+        let c = read_chart_xml(single.as_bytes()).unwrap();
+        assert!(c.series.iter().all(|s| !s.secondary_axis));
+    }
+
+    #[test]
+    fn text_sizes_are_read_from_the_file() {
+        // PowerPoint's new charts set the axes' and legend's text to 11.97 pt and the title's to
+        // 18.62 pt; a chart that only sets its overall text size uses it everywhere.
+        let ns =
+            r#"xmlns:c="http://schemas.openxmlformats.org/drawingml/2006/chart" xmlns:a="http://schemas.openxmlformats.org/drawingml/2006/main""#;
+        let tx = |sz: u32| format!(r#"<c:txPr><a:bodyPr/><a:p><a:pPr><a:defRPr sz="{sz}"/></a:pPr></a:p></c:txPr>"#);
+        let xml = format!(
+            r#"<c:chartSpace {ns}><c:chart><c:title><c:tx><c:rich><a:bodyPr/><a:p><a:pPr><a:defRPr sz="1862"/></a:pPr><a:r><a:t>T</a:t></a:r></a:p></c:rich></c:tx></c:title><c:plotArea><c:barChart><c:barDir val="col"/><c:axId val="1"/><c:axId val="2"/></c:barChart><c:catAx><c:axId val="1"/>{}</c:catAx><c:valAx><c:axId val="2"/>{}</c:valAx></c:plotArea></c:chart></c:chartSpace>"#,
+            tx(1197),
+            tx(1197)
+        );
+        let c = read_chart_xml(xml.as_bytes()).unwrap();
+        assert_eq!((c.text_size, c.title_size), (Some(11.97), Some(18.62)));
+        let xml = format!(
+            r#"<c:chartSpace {ns}><c:chart><c:plotArea><c:barChart><c:barDir val="col"/></c:barChart></c:plotArea></c:chart>{}</c:chartSpace>"#,
+            tx(1400)
+        );
+        let c = read_chart_xml(xml.as_bytes()).unwrap();
+        assert_eq!((c.text_size, c.title_size), (Some(14.0), None));
+        let xml = format!(
+            r#"<c:chartSpace {ns}><c:chart><c:plotArea><c:barChart><c:barDir val="col"/></c:barChart></c:plotArea></c:chart></c:chartSpace>"#
+        );
+        assert_eq!(read_chart_xml(xml.as_bytes()).unwrap().text_size, None, "no sizes: the renderer picks one");
+    }
+}

crates/pptx/src/read/dml.rs

@@ -116,7 +116,8 @@ pub fn gradient(f: &El) -> Gradient {
     } else {
         GradientShape::Linear { angle: 90.0, scaled: false }
     };
-    Gradient { stops, shape, rotate_with_shape: f.bool("rotWithShape").unwrap_or(true) }
+    let tile = f.child("tileRect").map(|r| [pct(r, "l"), pct(r, "t"), pct(r, "r"), pct(r, "b")].map(|v| v.unwrap_or(0.0).clamp(-10.0, 10.0)));
+    Gradient { tile: tile.unwrap_or_default(), stops, shape, rotate_with_shape: f.bool("rotWithShape").unwrap_or(true) }
 }
 
 /// `blipFill` (either `a:` or `p:`) → picture fill, registering the image as media.
@@ -124,7 +125,7 @@ pub fn blip_fill(imp: &mut Imp, part: &Part, bf: &El) -> Option<PictureFill> {
     let blip = bf.child("blip");
     let media = blip.and_then(|b| media_ref(imp, part, b));
     let media = media?;
-    let mut pf = PictureFill { media, ..Default::default() };
+    let mut pf = PictureFill { media, upright: !bf.bool("rotWithShape").unwrap_or(true), ..Default::default() };
     if let Some(b) = blip {
         for e in b.elements() {
             match e.local() {
@@ -134,6 +135,8 @@ pub fn blip_fill(imp: &mut Imp, part: &Part, bf: &El) -> Option<PictureFill> {
                     pf.adjust.contrast = pct(e, "contrast").unwrap_or(0.0).clamp(-1.0, 1.0);
                 }
                 "grayscl" => pf.adjust.grayscale = true,
+                "biLevel" => pf.adjust.bilevel = Some(pct(e, "thresh").unwrap_or(0.5).clamp(0.0, 1.0)),
+                "alphaInv" => pf.adjust.alpha_inv = true,
                 "duotone" => {
                     let cs: Vec<ColorRef> = e.elements().filter_map(color_el).collect();
                     if let [a, b] = cs.as_slice() {
@@ -257,6 +260,14 @@ pub fn effects(el: &El) -> Effects {
             "innerShdw" => fx.inner_shadow = Some(shadow(e, true)),
             "glow" => fx.glow = Some(Glow { color: color(e).unwrap_or(ColorRef::rgb(Rgba::BLACK)), radius: pt(e, "rad").unwrap_or(0.0).max(0.0) }),
             "softEdge" => fx.soft_edge = Some(pt(e, "rad").unwrap_or(0.0).max(0.0)),
+            "fillOverlay" => {
+                let fill = e.elements().find_map(|f| match f.local() {
+                    "solidFill" => color(f).map(|c| Fill::Solid { color: c }),
+                    "gradFill" => Some(Fill::Gradient(gradient(f))),
+                    _ => None,
+                });
+                fx.fill_overlay = fill.map(|fill| deckcraft_model::style::FillOverlay { blend: e.attr("blend").unwrap_or("over").to_string(), fill });
+            }
             "reflection" => {
                 fx.reflection = Some(Reflection {
                     blur: pt(e, "blurRad").unwrap_or(0.0),
@@ -608,5 +619,13 @@ mod tests {
         assert_eq!(b.vert, Some(TextDir::Vertical270));
         assert_eq!(b.columns, Some(2));
         assert_eq!(b.autofit, Some(AutoFit::Shrink { font_scale: 0.625, line_reduction: 0.2 }));
+        // mongolianVert is its own direction (PowerPoint runs its lines left to right) and is
+        // written back as it was read.
+        let d = parse(br#"<a:bodyPr vert="mongolianVert"/>"#).unwrap();
+        let b = body_pr(&d.root);
+        assert_eq!(b.vert, Some(TextDir::MongolianVertical));
+        assert_eq!(b.vert.map(|v| v.xml()), Some("mongolianVert"));
+        let d = parse(br#"<a:bodyPr vert="wordArtVertRtl"/>"#).unwrap();
+        assert_eq!(body_pr(&d.root).vert.map(|v| v.xml()), Some("wordArtVertRtl"));
     }
 }

crates/pptx/src/read/shapes.rs

@@ -436,7 +436,9 @@ fn smartart(imp: &mut Imp, part: &Part, gd: &El, frame: &Shape, depth: usize) ->
 }
 
 fn table(imp: &mut Imp, part: &Part, tbl: &El) -> Table {
-    let mut t = Table { style: "none".into(), first_row: false, band_row: false, ..Default::default() };
+    // A table naming no style is drawn by PowerPoint with thin dark grid lines ("No Style, Table
+    // Grid"), not without lines.
+    let mut t = Table { style: "grid".into(), first_row: false, band_row: false, ..Default::default() };
     if let Some(pr) = tbl.child("tblPr") {
         t.background = pr.elements().find(|e| e.local().ends_with("Fill") && e.local() != "noFill").and_then(|f| dml::fill_el(imp, part, f));
         t.first_row = pr.bool("firstRow").unwrap_or(false);

crates/pptx/src/write/chart.rs

@@ -467,7 +467,7 @@ pub fn chart_xml(c: &Chart) -> Vec<u8> {
         };
         w.open0("c:legend");
         w.val("c:legendPos", p);
-        w.val("c:overlay", 0);
+        w.val("c:overlay", u8::from(c.legend_overlay));
         w.close("c:legend");
     }
     w.val("c:plotVisOnly", 1);

crates/pptx/src/write/dml.rs

@@ -76,40 +76,7 @@ pub fn fill(w: &mut W, x: &mut Exp, o: &mut Out, f: &Fill) {
     match f {
         Fill::None => w.empty0("a:noFill"),
         Fill::Solid { color: c } => solid(w, c),
-        Fill::Gradient(g) => {
-            w.open("a:gradFill", A::new().a("rotWithShape", if g.rotate_with_shape { "1" } else { "0" }));
-            // No stops: no `a:gsLst`, so the gradient keeps taking them from its style's fill.
-            let mut stops = g.stops.clone();
-            if stops.len() == 1 {
-                let mut s = stops[0].clone();
-                s.pos = 1.0;
-                stops.push(s);
-            }
-            if !stops.is_empty() {
-                w.open0("a:gsLst");
-                for s in &stops {
-                    w.open("a:gs", A::new().a("pos", pct(s.pos.clamp(0.0, 1.0))));
-                    color(w, &s.color);
-                    w.close("a:gs");
-                }
-                w.close("a:gsLst");
-            }
-            match &g.shape {
-                GradientShape::Linear { angle, scaled } => {
-                    w.empty("a:lin", A::new().a("ang", ang(*angle)).a("scaled", if *scaled { "1" } else { "0" }))
-                }
-                GradientShape::Path { path, focus } => {
-                    let p = match path.as_str() {
-                        "rect" | "shape" | "circle" => path.as_str(),
-                        _ => "circle",
-                    };
-                    w.open("a:path", A::new().a("path", p));
-                    w.empty("a:fillToRect", A::new().a("l", pct(focus[0])).a("t", pct(focus[1])).a("r", pct(focus[2])).a("b", pct(focus[3])));
-                    w.close("a:path");
-                }
-            }
-            w.close("a:gradFill");
-        }
+        Fill::Gradient(g) => gradient(w, g),
         Fill::Picture(pf) => blip_fill(w, x, o, "a:blipFill", pf),
         Fill::Pattern(p) => {
             w.open("a:pattFill", A::new().a("prst", if p.preset.is_empty() { "pct5" } else { &p.preset }));
@@ -129,10 +96,16 @@ pub fn fill(w: &mut W, x: &mut Exp, o: &mut Out, f: &Fill) {
 /// `a:blipFill` / `p:blipFill`.
 pub fn blip_fill(w: &mut W, x: &mut Exp, o: &mut Out, tag: &str, pf: &PictureFill) {
     let rid = x.media_rel(o, pf.media, "image").unwrap_or_else(|| x.placeholder_rel(o));
-    w.open(tag, A::new().a("rotWithShape", "1"));
+    w.open(tag, A::new().a("rotWithShape", if pf.upright { "0" } else { "1" }));
     let adj = &pf.adjust;
-    let has_kids =
-        pf.alpha.is_some() || adj.brightness != 0.0 || adj.contrast != 0.0 || adj.grayscale || adj.duotone.is_some() || adj.clear_color.is_some();
+    let has_kids = pf.alpha.is_some()
+        || adj.brightness != 0.0
+        || adj.contrast != 0.0
+        || adj.grayscale
+        || adj.duotone.is_some()
+        || adj.clear_color.is_some()
+        || adj.bilevel.is_some()
+        || adj.alpha_inv;
     let a = A::new().a("r:embed", &rid);
     if has_kids {
         w.open("a:blip", a);
@@ -149,6 +122,12 @@ pub fn blip_fill(w: &mut W, x: &mut Exp, o: &mut Out, tag: &str, pf: &PictureFil
         if let Some(al) = pf.alpha {
             w.empty("a:alphaModFix", A::new().a("amt", pct(al.clamp(0.0, 1.0))));
         }
+        if adj.alpha_inv {
+            w.empty0("a:alphaInv");
+        }
+        if let Some(t) = adj.bilevel {
+            w.empty("a:biLevel", A::new().a("thresh", pct(t.clamp(0.0, 1.0))));
+        }
         if let Some((d, l)) = &adj.duotone {
             w.open0("a:duotone");
             color(w, d);
@@ -275,8 +254,59 @@ fn shadow(w: &mut W, tag: &str, s: &deckcraft_model::style::Shadow) {
     w.close(tag);
 }
 
+fn gradient(w: &mut W, g: &deckcraft_model::style::Gradient) {
+    w.open("a:gradFill", A::new().a("rotWithShape", if g.rotate_with_shape { "1" } else { "0" }));
+    // No stops: no `a:gsLst`, so the gradient keeps taking them from its style's fill.
+    let mut stops = g.stops.clone();
+    if stops.len() == 1 {
+        let mut s = stops[0].clone();
+        s.pos = 1.0;
+        stops.push(s);
+    }
+    if !stops.is_empty() {
+        w.open0("a:gsLst");
+        for s in &stops {
+            w.open("a:gs", A::new().a("pos", pct(s.pos.clamp(0.0, 1.0))));
+            color(w, &s.color);
+            w.close("a:gs");
+        }
+        w.close("a:gsLst");
+    }
+    match &g.shape {
+        GradientShape::Linear { angle, scaled } => w.empty("a:lin", A::new().a("ang", ang(*angle)).a("scaled", if *scaled { "1" } else { "0" })),
+        GradientShape::Path { path, focus } => {
+            let p = match path.as_str() {
+                "rect" | "shape" | "circle" => path.as_str(),
+                _ => "circle",
+            };
+            w.open("a:path", A::new().a("path", p));
+            w.empty("a:fillToRect", A::new().a("l", pct(focus[0])).a("t", pct(focus[1])).a("r", pct(focus[2])).a("b", pct(focus[3])));
+            w.close("a:path");
+        }
+    }
+    if g.tile.iter().any(|v| *v != 0.0) {
+        let [l, t, r, b] = g.tile;
+        w.empty("a:tileRect", A::new().a("l", pct(l)).a("t", pct(t)).a("r", pct(r)).a("b", pct(b)));
+    }
+    w.close("a:gradFill");
+}
+
 pub fn effects(w: &mut W, fx: &Effects) {
     w.open0("a:effectLst");
+    // Schema order: blur, fillOverlay, glow, innerShdw, outerShdw, prstShdw, reflection, softEdge.
+    if let Some(ov) = &fx.fill_overlay {
+        let blend = match ov.blend.as_str() {
+            b @ ("over" | "mult" | "screen" | "darken" | "lighten") => b,
+            _ => "over",
+        };
+        w.open("a:fillOverlay", A::new().a("blend", blend));
+        match &ov.fill {
+            Fill::Solid { color: c } => solid(w, c),
+            Fill::Gradient(g) => gradient(w, g),
+            _ => w.empty0("a:noFill"),
+        }
+        w.close("a:fillOverlay");
+    }
     if let Some(g) = &fx.glow {
         w.open("a:glow", A::new().a("rad", emu(g.radius).max(0)));
         color(w, &g.color);

crates/pptx/tests/fills.rs

@@ -88,7 +88,7 @@ fn a_gradient_without_stops_is_saved_without_stops() {
     let mut p = defaults::new_presentation(None);
     let id = ShapeId(p.alloc_id());
     let first = p.slides[0].id;
-    let own = Gradient { stops: vec![], shape: GradientShape::Linear { angle: 45.0, scaled: true }, rotate_with_shape: true };
+    let own = Gradient { tile: [0.0; 4], stops: vec![], shape: GradientShape::Linear { angle: 45.0, scaled: true }, rotate_with_shape: true };
     p.slide_mut(first).expect("slide").shapes.push(Shape {
         id,
         name: "Styled".into(),
@@ -102,3 +102,150 @@ fn a_gradient_without_stops_is_saved_without_stops() {
     let s = q.slides[0].shapes.iter().find(|s| s.name == "Styled").expect("shape");
     assert_eq!(s.fill, Some(Fill::Gradient(own)));
 }
+
+#[test]
+fn a_fill_overlay_round_trips() {
+    use deckcraft_model::style::{FillOverlay, Gradient, GradientShape, GradientStop};
+    let mut p = defaults::new_presentation(None);
+    let id = ShapeId(p.alloc_id());
+    let first = p.slides[0].id;
+    let overlay = FillOverlay {
+        blend: "mult".into(),
+        fill: Fill::Gradient(Gradient {
+            tile: [0.0; 4],
+            stops: vec![
+                GradientStop { pos: 0.0, color: deckcraft_model::ColorRef::scheme(deckcraft_color::SchemeSlot::Accent1) },
+                GradientStop { pos: 1.0, color: deckcraft_model::ColorRef::rgb(deckcraft_color::Rgba::rgb(10, 20, 30)) },
+            ],
+            shape: GradientShape::Linear { angle: 4.5, scaled: true },
+            rotate_with_shape: true,
+        }),
+    };
+    p.slide_mut(first).expect("slide").shapes.push(Shape {
+        id,
+        name: "Overlaid".into(),
+        xfrm: Some(Xfrm::new(10.0, 10.0, 200.0, 100.0)),
+        fill: Some(Fill::solid(deckcraft_model::ColorRef::rgb(deckcraft_color::Rgba::WHITE))),
+        effects: Some(deckcraft_model::Effects { fill_overlay: Some(overlay.clone()), ..Default::default() }),
+        ..Default::default()
+    });
+    let bytes = deckcraft_pptx::export(&p).expect("export");
+    let q = deckcraft_pptx::import(&bytes).expect("import");
+    let s = q.slides[0].shapes.iter().find(|s| s.name == "Overlaid").expect("shape");
+    assert_eq!(s.effects.as_ref().and_then(|e| e.fill_overlay.clone()), Some(overlay));
+}
+
+#[test]
+fn a_gradient_tile_rect_is_read_and_round_trips() {
+    use deckcraft_model::style::{Gradient, GradientShape, GradientStop};
+    // PowerPoint's "from top-left corner" radial: focus on the corner, tile reaching a box up and
+    // to the left so it centres on that corner.
+    let g = Gradient {
+        stops: vec![
+            GradientStop { pos: 0.0, color: deckcraft_model::ColorRef::rgb(deckcraft_color::Rgba::rgb(0, 128, 255)) },
+            GradientStop { pos: 1.0, color: deckcraft_model::ColorRef::rgb(deckcraft_color::Rgba::WHITE) },
+        ],
+        shape: GradientShape::Path { path: "circle".into(), focus: [0.0, 0.0, 1.0, 1.0] },
+        rotate_with_shape: true,
+        tile: [-1.0, -1.0, 0.0, 0.0],
+    };
+    let mut p = defaults::new_presentation(None);
+    let id = ShapeId(p.alloc_id());
+    let first = p.slides[0].id;
+    p.slide_mut(first).expect("slide").shapes.push(Shape {
+        id,
+        name: "Corner".into(),
+        xfrm: Some(Xfrm::new(10.0, 10.0, 200.0, 100.0)),
+        fill: Some(Fill::Gradient(g.clone())),
+        ..Default::default()
+    });
+    let bytes = deckcraft_pptx::export(&p).expect("export");
+    let q = deckcraft_pptx::import(&bytes).expect("import");
+    let s = q.slides[0].shapes.iter().find(|s| s.name == "Corner").expect("shape");
+    assert_eq!(s.fill, Some(Fill::Gradient(g)));
+    // As written by PowerPoint (attributes it leaves out are 0).
+    let edited =
+        edit_slides(&bytes, |x| x.replace("<a:tileRect l=\"-100000\" t=\"-100000\" r=\"0\" b=\"0\"/>", "<a:tileRect l=\"-100000\" t=\"-100000\"/>"));
+    let q = deckcraft_pptx::import(&edited).expect("import");
+    let s = q.slides[0].shapes.iter().find(|s| s.name == "Corner").expect("shape");
+    assert!(matches!(&s.fill, Some(Fill::Gradient(g)) if g.tile == [-1.0, -1.0, 0.0, 0.0]), "{:?}", s.fill);
+}
+
+#[test]
+fn a_table_naming_no_style_is_drawn_with_the_table_grid() {
+    let mut p = defaults::new_presentation(None);
+    let id = ShapeId(p.alloc_id());
+    let first = p.slides[0].id;
+    let mut t = deckcraft_model::Table::new(2, 2, 200.0, 40.0);
+    t.style = "none".into();
+    p.slide_mut(first).expect("slide").shapes.push(Shape {
+        id,
+        name: "Grid".into(),
+        xfrm: Some(Xfrm::new(10.0, 10.0, 200.0, 80.0)),
+        kind: deckcraft_model::ShapeKind::Table(t),
+        ..Default::default()
+    });
+    let bytes = deckcraft_pptx::export(&p).expect("export");
+    let style = |bytes: &[u8]| {
+        let q = deckcraft_pptx::import(bytes).expect("import");
+        let s = q.slides[0].shapes.iter().find(|s| s.name == "Grid").expect("shape").clone();
+        match s.kind {
+            deckcraft_model::ShapeKind::Table(t) => t.style,
+            other => panic!("{other:?}"),
+        }
+    };
+    // Written with its style, it reads back as written.
+    assert_eq!(style(&bytes), "none");
+    // Without a:tableStyleId PowerPoint draws thin dark grid lines.
+    let bare = edit_slides(&bytes, |x| {
+        let (Some(a), Some(b)) = (x.find("<a:tableStyleId>"), x.find("</a:tableStyleId>")) else { return x };
+        format!("{}{}", &x[..a], &x[b + "</a:tableStyleId>".len()..])
+    });
+    assert_eq!(style(&bare), "grid");
+}
+
+#[test]
+fn black_and_white_and_inverted_alpha_pictures_round_trip() {
+    let mut p = defaults::new_presentation(None);
+    let media = p.add_media("tile.png", "image/png", png());
+    let id = ShapeId(p.alloc_id());
+    let first = p.slides[0].id;
+    let mut pf = PictureFill { media, ..Default::default() };
+    pf.adjust.bilevel = Some(0.3);
+    pf.adjust.alpha_inv = true;
+    p.slide_mut(first).expect("slide").shapes.push(Shape {
+        id,
+        name: "BW".into(),
+        xfrm: Some(Xfrm::new(10.0, 10.0, 200.0, 100.0)),
+        fill: Some(Fill::Picture(pf)),
+        ..Default::default()
+    });
+    let bytes = deckcraft_pptx::export(&p).expect("export");
+    let q = deckcraft_pptx::import(&bytes).expect("import");
+    let s = q.slides[0].shapes.iter().find(|s| s.name == "BW").expect("shape");
+    match &s.fill {
+        Some(Fill::Picture(pf)) => assert_eq!((pf.adjust.bilevel, pf.adjust.alpha_inv), (Some(0.3), true)),
+        other => panic!("{other:?}"),
+    }
+}
+
+#[test]
+fn an_upright_picture_fill_round_trips() {
+    let bytes = deck();
+    let edited = edit_slides(&bytes, |x| x.replacen("rotWithShape=\"1\"", "rotWithShape=\"0\"", 1));
+    let q = deckcraft_pptx::import(&edited).expect("import");
+    let s = q.slides[0].shapes.iter().find(|s| s.name == "Textured").expect("shape");
+    let Some(Fill::Picture(pf)) = &s.fill else { panic!("{:?}", s.fill) };
+    assert!(pf.upright);
+    let again = deckcraft_pptx::export(&q).expect("export");
+    let r = deckcraft_pptx::import(&again).expect("import");
+    let s = r.slides[0].shapes.iter().find(|s| s.name == "Textured").expect("shape");
+    assert!(matches!(&s.fill, Some(Fill::Picture(pf)) if pf.upright));
+    // Rotating with the shape is the default.
+    assert!(matches!(textured_fill(&bytes), Some(Fill::Picture(pf)) if !pf.upright));
+}
+
+fn textured_fill(bytes: &[u8]) -> Option<Fill> {
+    let q = deckcraft_pptx::import(bytes).expect("import");
+    q.slides[0].shapes.iter().find(|s| s.name == "Textured").and_then(|s| s.fill.clone())
+}

crates/pptx/tests/roundtrip.rs

@@ -105,6 +105,7 @@ pub fn rich_deck() -> Presentation {
     let mut a = shape(&mut p, "Gradient Star", 100.0, 120.0, 150.0, 150.0);
     a.geom = Geom::Preset { name: "star5".into(), adj: vec![20000.0] };
     a.fill = Some(Fill::Gradient(Gradient {
+        tile: [0.0; 4],
         stops: vec![
             GradientStop { pos: 0.0, color: ColorRef::scheme(SchemeSlot::Accent1) },
             GradientStop { pos: 1.0, color: ColorRef::scheme(SchemeSlot::Accent2).with(ColorTransform::LumMod(75000)) },
@@ -230,6 +231,7 @@ pub fn rich_deck() -> Presentation {
             mode: PictureMode::Stretch { fill_rect: [0.0; 4] },
             alpha: Some(0.5),
             adjust: PictureAdjust { brightness: 0.2, contrast: -0.1, grayscale: true, ..Default::default() },
+            upright: false,
         },
     };
     let mut tiled = shape(&mut p, "Tiled", 350.0, 120.0, 200.0, 150.0);
@@ -857,3 +859,135 @@ fn wordart_warps_and_their_adjusts_round_trip() {
     assert_eq!(inflate.warp.as_deref(), Some("textInflate"));
     assert!(inflate.warp_adj.is_empty());
 }
+
+/// Slide XML of a deck exported with one slide per transition (kind, option, ms, advance after).
+fn transition_deck(list: &[(&str, &str, u32, Option<u32>)]) -> (Presentation, Vec<String>) {
+    let mut p = defaults::new_presentation(None);
+    let base = p.slides[0].as_ref().clone();
+    p.slides.clear();
+    for (kind, option, ms, adv) in list {
+        let mut s = base.clone();
+        s.id = SlideId(p.alloc_id());
+        s.transition = Some(Transition {
+            kind: kind.to_string(),
+            option: option.to_string(),
+            duration_ms: *ms,
+            advance_on_click: adv.is_none(),
+            advance_after_ms: *adv,
+            ..Default::default()
+        });
+        p.slides.push(Arc::new(s));
+    }
+    let bytes = deckcraft_pptx::export(&p).expect("export");
+    let mut zip = zip::ZipArchive::new(std::io::Cursor::new(bytes)).expect("zip");
+    let xml = (1..=list.len())
+        .map(|i| {
+            let mut x = String::new();
+            std::io::Read::read_to_string(&mut zip.by_name(&format!("ppt/slides/slide{i}.xml")).expect("slide"), &mut x).expect("read");
+            x
+        })
+        .collect();
+    (p, xml)
+}
+
+#[test]
+fn transition_xml_matches_powerpoints_elements() {
+    // The elements, attributes and namespaces PowerPoint itself writes for these effect options
+    // (observed on files it saved), inside `mc:AlternateContent` with a `p:fade` fallback for
+    // the 2010+ effects.
+    let cases: &[(&str, &str, &[&str], &str)] = &[
+        ("wipe", "ru", &[r#"<p:strips dir="ru"/>"#], "p14"),
+        ("wipe", "u", &[r#"<p:wipe dir="u"/>"#], "p14"),
+        ("zoom", "in", &[r#"<p14:warp dir="in"/>"#], "p14"),
+        ("zoom", "rotate", &["<p:newsflash/>"], "p14"),
+        ("shape", "out", &[r#"<p:zoom dir="out"/>"#], "p14"),
+        ("glitter", "hexD", &[r#"<p14:glitter dir="d" pattern="hexagon"/>"#], "p14"),
+        ("shred", "particlesOut", &[r#"<p14:shred pattern="rectangle" dir="out"/>"#], "p14"),
+        ("wind", "l", &[r#"<p15:prstTrans prst="wind" invX="1"/>"#], "p15"),
+        ("wind", "r", &[r#"<p15:prstTrans prst="wind"/>"#], "p15"),
+        ("fallOver", "r", &[r#"<p15:prstTrans prst="fallOver" invX="1"/>"#], "p15"),
+        ("pageCurlDouble", "singleR", &[r#"<p15:prstTrans prst="pageCurlSingle" invX="1"/>"#], "p15"),
+        ("orbit", "u", &[r#"<p14:prism dir="u" isContent="1" isInverted="1"/>"#], "p14"),
+        ("vortex", "r", &[r#"<p14:vortex dir="r"/>"#], "p14"),
+        ("morph", "words", &[r#"<p159:morph option="byWord"/>"#], "p159"),
+    ];
+    let list: Vec<(&str, &str, u32, Option<u32>)> = cases.iter().map(|c| (c.0, c.1, 2000, Some(1000))).collect();
+    let (p, xml) = transition_deck(&list);
+    for ((kind, option, wants, req), x) in cases.iter().zip(&xml) {
+        for w in *wants {
+            assert!(x.contains(w), "{kind}/{option}: {w} in {x}");
+        }
+        assert!(x.contains(&format!(r#"Requires="{req}""#)), "{kind}/{option}");
+        assert!(x.contains(r#"p14:dur="2000""#) && x.contains(r#"advTm="1000""#) && x.contains(r#"advClick="0""#), "{kind}/{option}");
+        assert!(x.contains("<mc:Fallback>"), "{kind}/{option}");
+    }
+    // Back in, everything is as it was.
+    let bytes = deckcraft_pptx::export(&p).expect("export");
+    let q = deckcraft_pptx::import(&bytes).expect("import");
+    for ((kind, option, ..), s) in cases.iter().zip(&q.slides) {
+        let t = s.transition.as_ref().expect("transition");
+        assert_eq!(
+            (t.kind.as_str(), t.option.as_str(), t.duration_ms, t.advance_after_ms, t.advance_on_click),
+            (*kind, *option, 2000, Some(1000), false)
+        );
+    }
+}
+
+#[test]
+fn transition_defaults_read_like_powerpoint() {
+    // PowerPoint leaves out an option when it is the element's default; these are its defaults.
+    let cases: &[(&str, &str, &str)] = &[
+        ("<p:push/>", "push", "l"),
+        ("<p:wipe/>", "wipe", "l"),
+        ("<p:strips/>", "wipe", "lu"),
+        ("<p:randomBar/>", "randomBar", "horz"),
+        ("<p:checker/>", "checker", "horz"),
+        ("<p:blinds/>", "blinds", "horz"),
+        ("<p:comb/>", "comb", "horz"),
+        ("<p:zoom/>", "shape", "out"),
+        (r#"<p:zoom dir="in"/>"#, "shape", "in"),
+        ("<p:split/>", "split", "horzOut"),
+        ("<p14:doors/>", "doors", "horz"),
+        ("<p14:window/>", "window", "horz"),
+        ("<p14:pan/>", "pan", "l"),
+        ("<p14:warp/>", "zoom", "out"),
+        ("<p14:glitter/>", "glitter", "l"),
+        ("<p14:shred/>", "shred", "stripsIn"),
+        ("<p14:reveal/>", "reveal", "smoothlyLeft"),
+        ("<p14:prism/>", "cube", "l"),
+        (r#"<p15:prstTrans prst="airplane"/>"#, "airplane", "r"),
+        (r#"<p15:prstTrans prst="peelOff"/>"#, "peelOff", "l"),
+        (r#"<p15:prstTrans prst="pageCurlSingle"/>"#, "pageCurlDouble", "singleL"),
+    ];
+    let (_, xml) = transition_deck(&[("fade", "smoothly", 2000, None)]);
+    let Some(x) = xml.first() else { panic!("no slide") };
+    let start = x.find("<mc:AlternateContent").expect("transition");
+    let end = x.find("</mc:AlternateContent>").expect("transition end") + "</mc:AlternateContent>".len();
+    let p14 = r#"xmlns:p14="http://schemas.microsoft.com/office/powerpoint/2010/main""#;
+    let p15 = r#"xmlns:p15="http://schemas.microsoft.com/office/powerpoint/2012/main""#;
+    for (el, kind, option) in cases {
+        let tr = format!(r#"<p:transition {p14} {p15} spd="slow" p14:dur="2000">{el}</p:transition>"#);
+        let edited = format!("{}{}{}", &x[..start], tr, &x[end..]);
+        let mut p = defaults::new_presentation(None);
+        let base = p.slides[0].as_ref().clone();
+        p.slides = vec![Arc::new(base)];
+        let bytes = deckcraft_pptx::export(&p).expect("export");
+        let mut zip = zip::ZipArchive::new(std::io::Cursor::new(bytes)).expect("zip");
+        let mut out = zip::ZipWriter::new(std::io::Cursor::new(Vec::new()));
+        for i in 0..zip.len() {
+            let mut f = zip.by_index(i).expect("entry");
+            let name = f.name().to_string();
+            let mut data = vec![];
+            std::io::Read::read_to_end(&mut f, &mut data).expect("read");
+            if name == "ppt/slides/slide1.xml" {
+                data = edited.clone().into_bytes();
+            }
+            out.start_file(name, zip::write::SimpleFileOptions::default()).expect("start");
+            std::io::Write::write_all(&mut out, &data).expect("write");
+        }
+        let bytes = out.finish().expect("finish").into_inner();
+        let q = deckcraft_pptx::import(&bytes).expect("import");
+        let t = q.slides[0].transition.as_ref().expect("transition");
+        assert_eq!((t.kind.as_str(), t.option.as_str(), t.duration_ms), (*kind, *option, 2000), "{el}");
+    }
+}

crates/render/Cargo.toml

@@ -13,6 +13,7 @@ deckcraft-geom = { workspace = true }
 deckcraft-color = { workspace = true }
 deckcraft-metafile = { workspace = true }
 deckcraft-model = { workspace = true }
+deckcraft-anim = { workspace = true }
 deckcraft-fonts = { workspace = true }
 deckcraft-text = { workspace = true }
 vello_cpu = { workspace = true }

crates/render/src/bevel.rs

@@ -0,0 +1,234 @@
+//! 3-D bevels (`a:sp3d/a:bevelT` seen through a `a:scene3d`), approximated in 2-D: the shape's
+//! face and a band inside its outline as wide as the bevel are lit as surfaces, the band's normal
+//! tilting out towards the outline by the bevel profile's slope.
+//!
+//! Fitted to PowerPoint's export of bevel presets on a solid-filled shape with the default
+//! three-point light rig and matte material: each channel comes out as
+//! `c · (0.453 + 0.731 · max(0, n · L)) + 14.7` for a light from the upper left (azimuth 240°,
+//! 45° up), within about 15 grey levels RMS across the band (exact profiles, specular highlights
+//! and the other rigs, materials and cameras are not modelled).
+
+use std::sync::Arc;
+
+use deckcraft_color::Rgba;
+use kurbo::{Affine, BezPath, Point, Rect};
+use vello_cpu::{Pixmap, RenderContext, peniko};
+
+/// Longest side of the rasterised lighting, in pixels.
+const MAX_SIDE: f64 = 512.0;
+const AMBIENT: f64 = 0.453;
+const DIFFUSE: f64 = 0.731;
+const SPECULAR: f64 = 14.7;
+
+/// A top bevel: its width and height in points and its preset.
+#[derive(Clone, Debug, PartialEq)]
+pub struct Bevel {
+    pub w: f64,
+    pub h: f64,
+    pub preset: String,
+    /// Lit as measured (the three-point rig and matte material); other rigs and materials are not
+    /// drawn.
+    pub modelled: bool,
+}
+
+/// The top bevel of 3-D XML kept from the file (`scene3d` + `sp3d`), when it has both a scene
+/// (without one PowerPoint draws the shape flat) and a `bevelT`.
+pub fn from_raw(raw: &str) -> Option<Bevel> {
+    if !raw.contains("scene3d") || !raw.contains("sp3d") {
+        return None;
+    }
+    // A 3-D shape without a bevel still has its face lit: a bevel of no width.
+    let Some(i) = raw.find("bevelT") else {
+        let b = Bevel { w: 0.0, h: 0.0, preset: "circle".into(), modelled: false };
+        return Some(Bevel { modelled: modelled(raw), ..b });
+    };
+    let tag = raw.get(i..)?;
+    let tag = tag.get(..tag.find('>')?)?;
+    let attr = |name: &str| -> Option<&str> {
+        let key = format!(" {name}=\"");
+        let s = tag.find(&key)? + key.len();
+        let rest = tag.get(s..)?;
+        rest.get(..rest.find('"')?)
+    };
+    let emu = |name: &str| attr(name).and_then(|v| v.parse::<f64>().ok()).map(|v| v / 12700.0);
+    let w = emu("w").unwrap_or(6.0).clamp(0.0, 2000.0);
+    let h = emu("h").unwrap_or(6.0).clamp(0.0, 2000.0);
+    (w > 0.0).then(|| Bevel { w, h, preset: attr("prst").unwrap_or("circle").to_string(), modelled: modelled(raw) })
+}
+
+/// Whether the light rig and material (from anywhere in the XML: `a:lightRig rig=`,
+/// `prstMaterial=`) are the ones measured: the three-point rig, matte.
+fn modelled(raw: &str) -> bool {
+    let value_after = |key: &str| -> Option<&str> {
+        let s = raw.find(key)? + key.len();
+        let rest = raw.get(s..)?;
+        rest.get(..rest.find('"')?)
+    };
+    let rig = value_after("rig=\"").unwrap_or("threePt");
+    let material = value_after("prstMaterial=\"").unwrap_or("warmMatte");
+    rig == "threePt" && matches!(material, "warmMatte" | "matte")
+}
+
+/// The light, pointing from the surface towards it (x right, y down, z towards the viewer).
+fn light() -> [f64; 3] {
+    let (az, el) = (240f64.to_radians(), 45f64.to_radians());
+    [el.cos() * az.cos(), el.cos() * az.sin(), el.sin()]
+}
+
+/// The bevel surface's rise per unit inwards (in units of h / w) at `u` (0 at the outline, 1 at
+/// the inner edge of the band), by preset.
+fn slope(preset: &str, u: f64) -> f64 {
+    let u = u.clamp(1e-3, 1.0);
+    match preset {
+        "angle" => 1.0,
+        // A quarter circle, steep at the outline and flat where it meets the face; the default,
+        // and used for the presets not modelled.
+        _ => {
+            let v = 1.0 - u;
+            v / (1.0 - v * v).max(1e-6).sqrt()
+        }
+    }
+}
+
+/// Lighting factor and outward edge normal at each position, for a polygon set: distance to the
+/// nearest edge and that edge's outward normal (edges oriented by each polygon's signed area).
+fn nearest_edge(polys: &[Vec<Point>], areas: &[f64], p: Point) -> Option<(f64, kurbo::Vec2)> {
+    let mut best: Option<(f64, kurbo::Vec2)> = None;
+    for (poly, area) in polys.iter().zip(areas) {
+        for w in poly.windows(2) {
+            let (a, b) = (w[0], w[1]);
+            let e = b - a;
+            let l2 = e.hypot2();
+            if l2 < 1e-12 {
+                continue;
+            }
+            let t = ((p - a).dot(e) / l2).clamp(0.0, 1.0);
+            let d = (p - (a + e * t)).hypot();
+            if best.is_none_or(|(bd, _)| d < bd) {
+                // Outward normal: for a polygon of positive (clockwise on screen, y down) area the
+                // outside is to the left of each edge's direction.
+                let n = kurbo::Vec2::new(e.y, -e.x) / l2.sqrt();
+                let n = if *area > 0.0 { n } else { -n };
+                best = Some((d, n));
+            }
+        }
+    }
+    best
+}
+
+/// Draw the lit face and bevel band over a shape filled with `fill` (a solid colour, or `None`
+/// for any other fill, which gets the band's highlights and shading as light and dark veils)
+/// inside `path` (shape space, laid out in `bounds`), `m` mapping it to the output.
+#[allow(clippy::too_many_arguments)]
+pub fn draw(ctx: &mut RenderContext, bevel: &Bevel, fill: Option<Rgba>, path: &BezPath, bounds: Rect, m: Affine, alpha: f64) {
+    // Other light rigs and materials light the face and band differently (brighter, darker,
+    // shinier); rather than guess, they stay flat as before.
+    if !bevel.modelled || bounds.width() <= 0.0 || bounds.height() <= 0.0 || !bounds.is_finite() {
+        return;
+    }
+    // No bevel: only the face, one lit colour (as PowerPoint lights a 3-D shape's front face,
+    // whichever way the camera turns it, within about 10 levels).
+    if bevel.w <= 0.0 {
+        if let Some(c) = fill {
+            let f = AMBIENT + DIFFUSE * light()[2];
+            let ch = |v: u8| (v as f64 * f + SPECULAR).round().clamp(0.0, 255.0) as u8;
+            ctx.set_transform(m);
+            ctx.set_paint(crate::color(Rgba::rgba(ch(c.r), ch(c.g), ch(c.b), c.a), alpha));
+            ctx.fill_path(path);
+        }
+        return;
+    }
+    let k = crate::scale_of(m);
+    let k = if k.is_finite() && k > 0.0 { k } else { 1.0 };
+    let longest = bounds.width().max(bounds.height()) * k;
+    let s = (MAX_SIDE / longest).min(1.0) * k;
+    let (pw, ph) = (((bounds.width() * s).ceil() as u32).clamp(1, 2048), ((bounds.height() * s).ceil() as u32).clamp(1, 2048));
+    let polys = crate::pathgrad::polygons(path);
+    if polys.is_empty() {
+        return;
+    }
+    let areas: Vec<f64> = polys.iter().map(|p| p.windows(2).map(|w| w[0].x * w[1].y - w[1].x * w[0].y).sum::<f64>() / 2.0).collect();
+    let l = light();
+    let face = AMBIENT + DIFFUSE * l[2];
+    let ratio = if bevel.w > 0.0 { bevel.h / bevel.w } else { 0.0 };
+    let a = alpha.clamp(0.0, 1.0);
+    let mut data = Vec::with_capacity((pw * ph) as usize);
+    for j in 0..ph {
+        for i in 0..pw {
+            let p = Point::new(bounds.x0 + (i as f64 + 0.5) / pw as f64 * bounds.width(), bounds.y0 + (j as f64 + 0.5) / ph as f64 * bounds.height());
+            let f = match nearest_edge(&polys, &areas, p) {
+                Some((d, e)) if d < bevel.w => {
+                    let z = slope(&bevel.preset, d / bevel.w) * ratio;
+                    let n = [e.x * z, e.y * z, 1.0];
+                    let len = (n[0] * n[0] + n[1] * n[1] + n[2] * n[2]).sqrt();
+                    let dot = (n[0] * l[0] + n[1] * l[1] + n[2] * l[2]) / len;
+                    AMBIENT + DIFFUSE * dot.max(0.0)
+                }
+                _ => face,
+            };
+            let px = match fill {
+                Some(c) => {
+                    let ch = |v: u8| (v as f64 * f + SPECULAR).round().clamp(0.0, 255.0);
+                    let ca = c.a as f64 * a / 255.0;
+                    let pm = |v: f64| (v * ca).round().clamp(0.0, 255.0) as u8;
+                    vello_cpu::color::PremulRgba8 { r: pm(ch(c.r)), g: pm(ch(c.g)), b: pm(ch(c.b)), a: (ca * 255.0).round() as u8 }
+                }
+                None => {
+                    // A veil: white where the band is lighter than the face, black where darker.
+                    let d = ((f - face) * 1.5).clamp(-1.0, 1.0);
+                    let va = (d.abs() * a * 255.0).round().clamp(0.0, 255.0) as u8;
+                    let v = if d > 0.0 { va } else { 0 };
+                    vello_cpu::color::PremulRgba8 { r: v, g: v, b: v, a: va }
+                }
+            };
+            data.push(px);
+        }
+    }
+    let pm = Arc::new(Pixmap::from_parts(data, pw as u16, ph as u16));
+    ctx.set_transform(m);
+    ctx.set_paint(vello_cpu::Image {
+        image: vello_cpu::ImageSource::Pixmap(pm),
+        sampler: peniko::ImageSampler { quality: peniko::ImageQuality::Medium, ..Default::default() },
+    });
+    ctx.set_paint_transform(
+        Affine::translate(bounds.origin().to_vec2()) * Affine::scale_non_uniform(bounds.width() / pw as f64, bounds.height() / ph as f64),
+    );
+    ctx.fill_path(path);
+    ctx.reset_paint_transform();
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn bevels_are_read_from_kept_3d_xml() {
+        let raw = r#"<a:scene3d><a:camera prst="orthographicFront"/></a:scene3d><a:sp3d><a:bevelT w="50800" h="16510" prst="angle"/></a:sp3d>"#;
+        assert_eq!(from_raw(raw), Some(Bevel { w: 4.0, h: 1.3, preset: "angle".into(), modelled: true }));
+        // Defaults: 6 pt square, circle.
+        let raw = r#"<a:scene3d/><a:sp3d><a:bevelT/></a:sp3d>"#;
+        assert_eq!(from_raw(raw), Some(Bevel { w: 6.0, h: 6.0, preset: "circle".into(), modelled: true }));
+        // Another rig or material: not modelled.
+        let raw = r#"<a:scene3d><a:lightRig rig="flood" dir="t"/></a:scene3d><a:sp3d prstMaterial="metal"><a:bevelT/></a:sp3d>"#;
+        assert!(from_raw(raw).is_some_and(|b| !b.modelled));
+        // No scene: flat in PowerPoint.
+        assert_eq!(from_raw(r#"<a:sp3d><a:bevelT w="50800"/></a:sp3d>"#), None);
+        // A 3-D shape with no bevel: a bevel of no width (its face is lit).
+        assert!(from_raw(r#"<a:scene3d/><a:sp3d extrusionH="10"/>"#).is_some_and(|b| b.w == 0.0 && b.modelled));
+        assert_eq!(from_raw(r#"<a:scene3d/>"#), None);
+    }
+
+    #[test]
+    fn the_light_comes_from_the_upper_left() {
+        let l = light();
+        assert!(l[0] < 0.0 && l[1] < 0.0 && l[2] > 0.0);
+        // An upward-facing edge (outward normal up) is lit more than a downward one.
+        let lit = |e: [f64; 2]| {
+            let z = slope("circle", 0.3) * 0.5;
+            let n = [e[0] * z, e[1] * z, 1.0];
+            let len = (n[0] * n[0] + n[1] * n[1] + 1.0).sqrt();
+            (n[0] * l[0] + n[1] * l[1] + n[2] * l[2]) / len
+        };
+        assert!(lit([0.0, -1.0]) > lit([-1.0, 0.0]) && lit([-1.0, 0.0]) > lit([1.0, 0.0]) && lit([1.0, 0.0]) > lit([0.0, 1.0]));
+    }
+}

crates/render/src/camera.rs

@@ -0,0 +1,202 @@
+//! 3-D cameras (`a:scene3d/a:camera`) turning a flat shape, approximated in 2-D.
+//!
+//! A shape seen through a 3-D camera preset (isometric, perspective…) or rotated with
+//! `a:camera/a:rot` is drawn by PowerPoint as its plane turned in space and projected. DeckCraft
+//! turns the shape's corners the same way and draws the shape under the affine transform that best
+//! fits them: exact for orthographic cameras, within about 2% of the shape's size for the
+//! perspective ones (whose foreshortening an affine transform can't show). Depth, bevels' sides and
+//! lighting are not drawn.
+//!
+//! The presets' turns were fitted to PowerPoint's exports (black-box: a picture with coloured
+//! corner markers under each preset, all fits within half a point on a 100 × 75 pt shape):
+//! points relative to the shape's centre are turned `p = Rz(-rev) · Rx(lat) · Ry(lon) · (x, y, 0)`
+//! and, for perspective cameras, scaled by `D / (D - p.z)` with `D = dist · max(w, h)`.
+
+use kurbo::{Affine, Point};
+
+/// (preset, lat, lon, rev in degrees, perspective distance in shape sizes or 0 for orthographic).
+const PRESETS: &[(&str, f64, f64, f64, f64)] = &[
+    ("orthographicFront", 0.0, 0.0, 0.0, 0.0),
+    ("isometricTopUp", 215.52, 134.75, 240.17, 0.0),
+    ("isometricTopDown", 324.69, 45.30, 299.88, 0.0),
+    ("isometricBottomUp", 215.52, 134.75, 240.17, 0.0),
+    ("isometricBottomDown", 215.36, 225.28, 119.86, 0.0),
+    ("isometricLeftUp", 324.94, 44.77, 0.03, 0.0),
+    ("isometricLeftDown", 144.84, 224.73, 179.95, 0.0),
+    ("isometricRightUp", 324.81, 44.75, 359.98, 0.0),
+    ("isometricRightDown", 144.84, 224.73, 179.95, 0.0),
+    ("isometricOffAxis1Left", 17.94, 64.06, 359.94, 0.0),
+    ("isometricOffAxis1Right", 341.80, 25.84, 0.0, 0.0),
+    ("isometricOffAxis1Top", 238.56, 127.22, 237.03, 0.0),
+    ("isometricOffAxis2Left", 161.88, 205.84, 179.98, 0.0),
+    ("isometricOffAxis2Right", 197.91, 244.06, 180.06, 0.0),
+    ("isometricOffAxis2Top", 301.42, 52.80, 302.97, 0.0),
+    ("isometricOffAxis3Left", 197.95, 244.05, 180.06, 0.0),
+    ("isometricOffAxis3Right", 161.88, 205.84, 179.98, 0.0),
+    ("isometricOffAxis3Bottom", 301.42, 52.78, 302.98, 0.0),
+    ("isometricOffAxis4Left", 198.00, 205.84, 180.05, 0.0),
+    ("isometricOffAxis4Right", 17.94, 64.06, 359.94, 0.0),
+    ("isometricOffAxis4Bottom", 121.42, 232.75, 237.00, 0.0),
+    ("perspectiveLeft", 359.91, 341.75, 0.02, 12.14),
+    ("perspectiveRight", 180.27, 198.23, 179.94, 8.02),
+    ("perspectiveAbove", 18.92, 0.38, 0.09, 16.61),
+    ("perspectiveBelow", 198.83, 180.39, 179.89, 9.31),
+    ("perspectiveAboveLeftFacing", 320.78, 346.02, 340.95, 11.54),
+    ("perspectiveAboveRightFacing", 219.25, 194.14, 198.98, 9.28),
+    ("perspectiveContrastingLeftFacing", 190.42, 136.41, 176.42, 12.21),
+    ("perspectiveContrastingRightFacing", 190.52, 223.59, 183.56, 9.53),
+    ("perspectiveHeroicLeftFacing", 10.89, 346.28, 2.75, 13.22),
+    ("perspectiveHeroicRightFacing", 169.53, 194.00, 177.22, 8.45),
+    ("perspectiveHeroicExtremeLeftFacing", 351.98, 325.89, 357.00, 5.98),
+    ("perspectiveHeroicExtremeRightFacing", 188.39, 214.22, 182.81, 5.26),
+    ("perspectiveRelaxed", 50.02, 0.03, 0.0, 11.32),
+    ("perspectiveRelaxedModerately", 34.42, 0.33, 0.16, 11.14),
+];
+
+/// Perspective distance for a perspective camera given its own rotation (fitted on
+/// `perspectiveFront` with `a:rot`, about 11 shape sizes).
+const PERSPECTIVE_DIST: f64 = 11.0;
+
+/// A camera's turn of the shape's plane.
+#[derive(Clone, Copy, Debug, PartialEq)]
+pub struct Camera {
+    pub lat: f64,
+    pub lon: f64,
+    pub rev: f64,
+    /// Perspective distance in shape sizes; 0 for an orthographic camera.
+    pub dist: f64,
+}
+
+/// The value of attribute `name` in the first `tag` element of `raw` (XML as kept from the file).
+fn attr<'a>(tag: &'a str, name: &str) -> Option<&'a str> {
+    let key = format!(" {name}=\"");
+    let s = tag.find(&key)? + key.len();
+    let rest = tag.get(s..)?;
+    rest.get(..rest.find('"')?)
+}
+
+/// The camera of 3-D XML kept from the file, when it turns the shape.
+pub fn from_raw(raw: &str) -> Option<Camera> {
+    let i = raw.find("camera ")?;
+    let rest = raw.get(i..)?;
+    let open_end = rest.find('>')?;
+    let open = rest.get(..open_end)?;
+    let prst = attr(open, "prst").unwrap_or("orthographicFront");
+    let preset = PRESETS.iter().find(|p| p.0 == prst);
+    let perspective = prst.starts_with("perspective");
+    // Its own `a:rot` (inside the camera element, not the light rig's).
+    let self_closing = open.ends_with('/');
+    let own_rot = if self_closing {
+        None
+    } else {
+        let body = rest.get(open_end..rest.find("camera>").unwrap_or(rest.len()))?;
+        body.find("rot ").and_then(|j| {
+            let t = body.get(j..)?;
+            let t = t.get(..t.find('>')?)?;
+            let deg = |n: &str| attr(t, n).and_then(|v| v.parse::<f64>().ok()).map(|v| v / 60000.0).unwrap_or(0.0);
+            Some((deg("lat"), deg("lon"), deg("rev")))
+        })
+    };
+    let cam = match (own_rot, preset) {
+        // PowerPoint turns the other way about the horizontal and vertical axes for `a:rot`.
+        (Some((lat, lon, rev)), p) => {
+            let dist = match p {
+                Some(p) if p.4 > 0.0 => p.4,
+                _ if perspective => PERSPECTIVE_DIST,
+                _ => 0.0,
+            };
+            Camera { lat: -lat, lon: -lon, rev, dist }
+        }
+        (None, Some(p)) => Camera { lat: p.1, lon: p.2, rev: p.3, dist: p.4 },
+        (None, None) => return None,
+    };
+    let flat = [cam.lat, cam.lon, cam.rev].iter().all(|a| (a.rem_euclid(360.0)).min(360.0 - a.rem_euclid(360.0)) < 1e-6);
+    (!flat).then_some(cam)
+}
+
+/// Where a point of the shape (relative to its centre) lands.
+fn project(c: &Camera, p: Point, size: f64) -> Point {
+    let (a, b, r) = (c.lat.to_radians(), c.lon.to_radians(), -c.rev.to_radians());
+    let (x1, y1, z1) = (p.x * b.cos(), p.y, -p.x * b.sin());
+    let (x2, y2, z2) = (x1, y1 * a.cos() - z1 * a.sin(), y1 * a.sin() + z1 * a.cos());
+    let (x3, y3) = (x2 * r.cos() - y2 * r.sin(), x2 * r.sin() + y2 * r.cos());
+    if c.dist > 0.0 {
+        let d = c.dist * size;
+        let s = d / (d - z2);
+        if s.is_finite() && s > 0.0 {
+            return Point::new(x3 * s, y3 * s);
+        }
+    }
+    Point::new(x3, y3)
+}
+
+/// The transform (shape space to shape space) that turns a `w` × `h` shape as camera `c` does:
+/// the affine map best fitting its turned corners.
+pub fn affine(c: &Camera, w: f64, h: f64) -> Option<Affine> {
+    if !(w.is_finite() && h.is_finite()) || w <= 0.0 || h <= 0.0 {
+        return None;
+    }
+    let size = w.max(h);
+    let src = [(-w / 2.0, -h / 2.0), (w / 2.0, -h / 2.0), (w / 2.0, h / 2.0), (-w / 2.0, h / 2.0)];
+    let dst: Vec<Point> = src.iter().map(|(x, y)| project(c, Point::new(*x, *y), size)).collect();
+    // Least squares over the four corners. The corners are symmetric about the centre, so the
+    // normal equations are diagonal: x' = a x + b y + e with a = Σ x x' / Σ x², and so on.
+    let (sxx, syy) = (src.iter().map(|p| p.0 * p.0).sum::<f64>(), src.iter().map(|p| p.1 * p.1).sum::<f64>());
+    let dot = |f: &dyn Fn(&(f64, f64), &Point) -> f64| src.iter().zip(&dst).map(|(s, d)| f(s, d)).sum::<f64>();
+    let a = dot(&|s, d| s.0 * d.x) / sxx;
+    let b = dot(&|s, d| s.1 * d.x) / syy;
+    let cc = dot(&|s, d| s.0 * d.y) / sxx;
+    let dd = dot(&|s, d| s.1 * d.y) / syy;
+    let e = dot(&|_, d| d.x) / 4.0;
+    let f = dot(&|_, d| d.y) / 4.0;
+    let local = Affine::new([a, cc, b, dd, e, f]);
+    let m = Affine::translate((w / 2.0, h / 2.0)) * local * Affine::translate((-w / 2.0, -h / 2.0));
+    (m.is_finite() && m.determinant().abs() > 1e-9).then_some(m)
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn corners(m: Affine, w: f64, h: f64) -> Vec<Point> {
+        [(0.0, 0.0), (w, 0.0), (w, h), (0.0, h)].iter().map(|(x, y)| m * Point::new(*x, *y)).collect()
+    }
+
+    #[test]
+    fn turning_about_the_vertical_axis_narrows_the_shape() {
+        // orthographicFront with lon 60: half as wide, as tall (PowerPoint: 0.506 of the width).
+        let c = from_raw(r#"<a:scene3d><a:camera prst="orthographicFront"><a:rot lat="0" lon="3600000" rev="0"/></a:camera><a:lightRig rig="threePt" dir="t"><a:rot lat="0" lon="0" rev="1200000"/></a:lightRig></a:scene3d>"#).unwrap();
+        let m = affine(&c, 100.0, 75.0).unwrap();
+        let k = corners(m, 100.0, 75.0);
+        assert!((k[1].x - k[0].x - 50.0).abs() < 0.01 && (k[3].y - k[0].y - 75.0).abs() < 0.01, "{k:?}");
+        assert!(((k[0].x + k[1].x) / 2.0 - 50.0).abs() < 1e-9, "about the centre");
+    }
+
+    #[test]
+    fn presets_turn_the_shape_as_powerpoint_does() {
+        // isometricTopUp, 100 × 75: PowerPoint's corners at (-1.247, 0.127), (0.170, -0.955),
+        // (1.237, -0.141), (-0.181, 0.941) of the half sizes from the centre.
+        let c = from_raw(r#"<a:scene3d><a:camera prst="isometricTopUp"/><a:lightRig rig="threePt" dir="t"/></a:scene3d>"#).unwrap();
+        let k = corners(affine(&c, 100.0, 75.0).unwrap(), 100.0, 75.0);
+        for (p, (u, v)) in k.iter().zip([(-1.247, 0.127), (0.170, -0.955), (1.237, -0.141), (-0.181, 0.941)]) {
+            let (x, y) = ((p.x - 50.0) / 50.0, (p.y - 37.5) / 37.5);
+            assert!((x - u).abs() < 0.03 && (y - v).abs() < 0.03, "({x:.3}, {y:.3}) vs ({u}, {v})");
+        }
+        // Front-facing cameras and the oblique ones leave a flat shape as it is.
+        for raw in [r#"<a:scene3d><a:camera prst="orthographicFront"/></a:scene3d>"#, r#"<a:scene3d><a:camera prst="obliqueTopLeft"/></a:scene3d>"#] {
+            assert_eq!(from_raw(raw), None);
+        }
+        assert_eq!(from_raw("<a:sp3d/>"), None);
+    }
+
+    #[test]
+    fn a_perspective_camera_is_approximated_closely() {
+        // perspectiveContrastingLeftFacing on 100 × 75: PowerPoint's corners within 3% of the size.
+        let c = from_raw(r#"<a:scene3d><a:camera prst="perspectiveContrastingLeftFacing"/></a:scene3d>"#).unwrap();
+        let k = corners(affine(&c, 100.0, 75.0).unwrap(), 100.0, 75.0);
+        for (p, (u, v)) in k.iter().zip([(-0.657, -1.189), (0.791, -0.795), (0.685, 1.244), (-0.742, 0.729)]) {
+            let (dx, dy) = (p.x - 50.0 - u * 50.0, p.y - 37.5 - v * 37.5);
+            assert!(dx.hypot(dy) < 3.0, "{p:?} vs ({u}, {v})");
+        }
+    }
+}

crates/render/src/chart.rs

@@ -2,7 +2,7 @@
 
 use deckcraft_color::{ColorTransform, Rgba, SchemeSlot};
 use deckcraft_model::Shape;
-use deckcraft_model::chart::{Chart, ChartType, nice_scale};
+use deckcraft_model::chart::{Chart, ChartType, axis_scale};
 use deckcraft_model::resolve::Ctx;
 use deckcraft_model::style::{ColorRef, Fill};
 use deckcraft_model::text::{Align, Anchor, Bullet, TextBody};
@@ -36,6 +36,29 @@ fn series_fill(ctx: &Ctx, c: &Chart, i: usize, s: Option<&deckcraft_model::chart
     }
 }
 
+/// A line series' colour: its line's own (where PowerPoint keeps it), else its fill's, else the
+/// palette's.
+fn series_line(ctx: &Ctx, c: &Chart, i: usize, s: &deckcraft_model::chart::Series) -> Rgba {
+    match s.line.as_ref().and_then(|l| l.fill.as_ref()) {
+        Some(Fill::Solid { color: cc }) => ctx.color(cc, None),
+        _ => series_fill(ctx, c, i, Some(s)),
+    }
+}
+
+/// A category label on two lines, split at its middle space or dash ("03.11.2025 - 09.11.2025").
+fn split_label(name: &str) -> String {
+    let chars: Vec<char> = name.chars().collect();
+    let mid = chars.len() / 2;
+    let best = chars.iter().enumerate().filter(|(_, c)| c.is_whitespace()).map(|(i, _)| i).min_by_key(|i| i.abs_diff(mid));
+    match best {
+        Some(i) if i > 0 && i + 1 < chars.len() => {
+            let (a, b) = chars.split_at(i);
+            format!("{}\n{}", a.iter().collect::<String>().trim_end(), b.iter().collect::<String>().trim_start())
+        }
+        _ => name.to_string(),
+    }
+}
+
 fn label(ctx: &mut RenderContext, rctx: &Ctx, m: Affine, text: &str, r: Rect, size: f64, align: Align, anchor: Anchor, col: Rgba, bold: bool) {
     let mut body = TextBody::from_text(text);
     body.body.inset_l = Some(0.0);
@@ -63,6 +86,42 @@ fn fmt_num(v: f64) -> String {
     if (v - v.round()).abs() < 1e-9 { format!("{}", v.round() as i64) } else { format!("{v:.1}") }
 }
 
+/// Where the legend goes for `c:legendPos`, and the plot area left over.
+/// `size` is the legend block (width, height); the result is its top-left corner and the plot area.
+/// `r` (also the OOXML default and the fallback for unknown values) and `l` are vertical stacks centred
+/// on the area, `tr` is a vertical stack in the top-right corner, `t` and `b` are centred rows.
+/// An overlaid legend leaves the plot area as it was.
+fn legend_layout(pos: &str, size: (f64, f64), area: Rect, base: f64, overlay: bool) -> (Point, Rect) {
+    let (lw, lh) = size;
+    let gap = base * 0.5;
+    let cx = (area.x0 + area.x1) / 2.0;
+    let cy = ((area.y0 + area.y1) / 2.0 - lh / 2.0).max(area.y0);
+    let mut plot = area;
+    let origin = match pos {
+        "b" => {
+            plot.y1 = area.y1 - lh - gap;
+            Point::new(cx - lw / 2.0, area.y1 - lh)
+        }
+        "t" => {
+            plot.y0 = area.y0 + lh + gap;
+            Point::new(cx - lw / 2.0, area.y0)
+        }
+        "l" => {
+            plot.x0 = area.x0 + lw + gap;
+            Point::new(area.x0, cy)
+        }
+        "tr" => {
+            plot.x1 = area.x1 - lw - gap;
+            Point::new(area.x1 - lw, area.y0)
+        }
+        _ => {
+            plot.x1 = area.x1 - lw - gap;
+            Point::new(area.x1 - lw, cy)
+        }
+    };
+    (origin, if overlay { area } else { plot })
+}
+
 pub fn draw(ctx: &mut RenderContext, rctx: &Ctx, c: &Chart, m: Affine, w: f64, h: f64) {
     let text_col = c.text_color.as_ref().map(|t| rctx.color(t, None)).unwrap_or(Rgba::rgb(0x59, 0x59, 0x59));
     let grid_col = Rgba::rgb(0xD9, 0xD9, 0xD9);
@@ -80,32 +139,53 @@ pub fn draw(ctx: &mut RenderContext, rctx: &Ctx, c: &Chart, m: Affine, w: f64, h
             rctx.pres,
         );
     }
-    let base = (h.min(w) / 22.0).clamp(7.0, 18.0);
+    // The file's text sizes when it has them (PowerPoint draws chart text at them); otherwise a size
+    // that suits the chart.
+    let base = c.text_size.unwrap_or_else(|| (h.min(w) / 22.0).clamp(7.0, 18.0));
+    let title_size = c.title_size.unwrap_or(base * 1.4);
     let mut area = Rect::new(w * 0.04, h * 0.04, w * 0.96, h * 0.96);
     if let Some(t) = &c.title {
-        label(ctx, rctx, m, t, Rect::new(0.0, area.y0, w, area.y0 + base * 1.8), base * 1.4, Align::Center, Anchor::Top, text_col, false);
-        area.y0 += base * 2.4;
+        label(ctx, rctx, m, t, Rect::new(0.0, area.y0, w, area.y0 + title_size * 1.3), title_size, Align::Center, Anchor::Top, text_col, false);
+        area.y0 += title_size * 1.7;
     }
     let pie = matches!(c.kind, ChartType::Pie | ChartType::Doughnut);
-    // Legend at the bottom.
+    // Legend placed by `c:legendPos`.
     let legend_items: Vec<(String, Rgba)> = if pie {
         c.categories.iter().enumerate().map(|(i, n)| (n.clone(), series_color(rctx, c, i))).collect()
     } else {
-        c.series.iter().enumerate().map(|(i, s)| (s.name.clone(), series_fill(rctx, c, i, Some(s)))).collect()
+        c.series
+            .iter()
+            .enumerate()
+            .map(|(i, s)| {
+                let k = c.series_kind(s);
+                let line = !k.is_bar_like() && !matches!(k, ChartType::Area | ChartType::StackedArea | ChartType::FilledRadar);
+                (s.name.clone(), if line { series_line(rctx, c, i, s) } else { series_fill(rctx, c, i, Some(s)) })
+            })
+            .collect()
     };
-    if c.legend.is_some() && !legend_items.is_empty() {
-        let ly = area.y1 - base * 1.4;
-        let item_w = (legend_items.iter().map(|(n, _)| n.chars().count() as f64 * base * 0.55 + base * 1.6).sum::<f64>()).min(w * 0.9);
-        let mut x = (w - item_w) / 2.0;
+    if let (Some(pos), false) = (&c.legend, legend_items.is_empty()) {
+        let vertical = matches!(pos.as_str(), "l" | "r" | "tr");
+        let item_ws: Vec<f64> = legend_items.iter().map(|(n, _)| n.chars().count() as f64 * base * 0.55 + base * 1.6).collect();
+        let size = if vertical {
+            (item_ws.iter().copied().fold(0.0, f64::max).min(w * 0.4), legend_items.len() as f64 * base * 1.5)
+        } else {
+            (item_ws.iter().sum::<f64>().min(w * 0.9), base * 1.4)
+        };
+        let (origin, plot_area) = legend_layout(pos, size, area, base, c.legend_overlay);
+        area = plot_area;
+        let (mut x, mut y) = (origin.x, origin.y);
         for (name, col) in &legend_items {
             ctx.set_transform(m);
             ctx.set_paint(color(*col, 1.0));
-            ctx.fill_rect(&Rect::new(x, ly + base * 0.3, x + base * 0.7, ly + base));
+            ctx.fill_rect(&Rect::new(x, y + base * 0.3, x + base * 0.7, y + base));
             let tw = name.chars().count() as f64 * base * 0.55 + base;
-            label(ctx, rctx, m, name, Rect::new(x + base, ly, x + base + tw, ly + base * 1.3), base, Align::Left, Anchor::Middle, text_col, false);
-            x += tw + base * 0.6;
+            label(ctx, rctx, m, name, Rect::new(x + base, y, x + base + tw, y + base * 1.3), base, Align::Left, Anchor::Middle, text_col, false);
+            if vertical {
+                y += base * 1.5;
+            } else {
+                x += tw + base * 0.6;
+            }
         }
-        area.y1 = ly - base * 0.5;
     }
     if pie {
         let Some(s) = c.series.first() else { return };
@@ -162,26 +242,50 @@ pub fn draw(ctx: &mut RenderContext, rctx: &Ctx, c: &Chart, m: Affine, w: f64, h
         }
         return;
     }
-    let (lo, hi) = c.value_range();
-    let (min, max, step) = nice_scale(lo.min(0.0), hi);
-    let horiz = c.kind.horizontal();
-    // Axis label gutter.
-    let gutter = base * 3.0;
-    let plot = if horiz {
-        Rect::new(area.x0 + gutter * 1.5, area.y0, area.x1, area.y1 - base * 1.6)
+    let combo = c.kind == ChartType::Combo;
+    // Bars are drawn first and lines over them; a combo chart has both.
+    let bar_kind = c.series.iter().map(|s| c.series_kind(s)).find(|k| k.is_bar_like());
+    let horiz = if combo { bar_kind.is_some_and(ChartType::horizontal) } else { c.kind.horizontal() };
+    // As many major units as the value axis has room for labels (PowerPoint's automatic unit).
+    let axis_len = if horiz { area.width() - base * 4.5 } else { area.height() - base * 1.8 };
+    let max_intervals = (axis_len / if horiz { base * 6.0 } else { base * 1.9 }).floor().clamp(2.0, 12.0) as usize;
+    let (min, max, step) = c.axis_scale(false, max_intervals).unwrap_or_else(|| axis_scale(0.0, 1.0, None, None, None, max_intervals, true));
+    // A combo chart's secondary value axis, on the right (vertical value axes only).
+    let second = if horiz { None } else { c.axis_scale(true, max_intervals) };
+    let ticks = |(lo, hi, st): (f64, f64, f64)| {
+        let n = (((hi - lo) / st.max(1e-12)).round() as i64).clamp(1, 50);
+        (0..=n).map(move |k| lo + k as f64 * st)
+    };
+    // Label gutters as wide as the longest value label.
+    let label_w =
+        |sec: bool, sc: (f64, f64, f64)| ticks(sc).map(|v| c.axis_label(sec, v).chars().count()).max().unwrap_or(1) as f64 * base * 0.55 + base * 0.6;
+    let gutter = if horiz {
+        base * 4.5
+    } else if c.y_hidden {
+        base * 0.5
     } else {
-        Rect::new(area.x0 + gutter, area.y0, area.x1, area.y1 - base * 1.8)
+        label_w(false, (min, max, step)).clamp(base * 1.5, area.width() * 0.3)
+    };
+    let gutter_r = second.filter(|_| !c.y2_hidden).map(|sc| label_w(true, sc).clamp(base * 1.5, area.width() * 0.3)).unwrap_or(0.0);
+    let plot = if horiz {
+        Rect::new(area.x0 + gutter, area.y0, area.x1, area.y1 - base * 1.6)
+    } else {
+        Rect::new(area.x0 + gutter, area.y0, area.x1 - gutter_r, area.y1 - base * 1.8)
     };
     if let Some(f) = &c.plot_fill {
         crate::paint::fill_path(ctx, rctx, f, None, &plot.to_path(0.1), plot, m, deckcraft_geom::preset::FillMode::Norm, 1.0, rctx.pres);
     }
     let span = (max - min).max(1e-9);
     let to_v = |v: f64| if horiz { plot.x0 + (v - min) / span * plot.width() } else { plot.y1 - (v - min) / span * plot.height() };
+    // A series' value as a position on its own axis.
+    let to_axis = |sec: bool, v: f64| match (sec, second) {
+        (true, Some((min2, max2, _))) => plot.y1 - (v - min2) / (max2 - min2).max(1e-9) * plot.height(),
+        _ => to_v(v),
+    };
     // Gridlines and value labels.
-    let n_steps = ((span / step).round() as i64).clamp(1, 50);
-    for k in 0..=n_steps {
-        let v = min + k as f64 * step;
+    for v in ticks((min, max, step)) {
         let pos = to_v(v);
+        let text = if c.y_hidden { String::new() } else { c.axis_label(false, v) };
         let mut g = BezPath::new();
         if horiz {
             g.move_to((pos, plot.y0));
@@ -190,7 +294,7 @@ pub fn draw(ctx: &mut RenderContext, rctx: &Ctx, c: &Chart, m: Affine, w: f64, h
                 ctx,
                 rctx,
                 m,
-                &fmt_num(v),
+                &text,
                 Rect::new(pos - 30.0, plot.y1 + 2.0, pos + 30.0, plot.y1 + base * 1.5),
                 base,
                 Align::Center,
@@ -205,7 +309,7 @@ pub fn draw(ctx: &mut RenderContext, rctx: &Ctx, c: &Chart, m: Affine, w: f64, h
                 ctx,
                 rctx,
                 m,
-                &fmt_num(v),
+                &text,
                 Rect::new(area.x0, pos - base, plot.x0 - base * 0.4, pos + base),
                 base,
                 Align::Right,
@@ -221,9 +325,28 @@ pub fn draw(ctx: &mut RenderContext, rctx: &Ctx, c: &Chart, m: Affine, w: f64, h
             ctx.stroke_path(&g);
         }
     }
+    // The secondary axis' labels, on the right, without gridlines of their own.
+    if let Some(sc) = second.filter(|_| !c.y2_hidden) {
+        for v in ticks(sc) {
+            let pos = to_axis(true, v);
+            label(
+                ctx,
+                rctx,
+                m,
+                &c.axis_label(true, v),
+                Rect::new(plot.x1 + base * 0.4, pos - base, area.x1, pos + base),
+                base,
+                Align::Left,
+                Anchor::Middle,
+                text_col,
+                false,
+            );
+        }
+    }
     let ncat = c.categories.len().max(c.series.iter().map(|s| s.values.len()).max().unwrap_or(0)).max(1);
     let band = if horiz { plot.height() / ncat as f64 } else { plot.width() / ncat as f64 };
-    // Category labels.
+    // Category labels: wrapped onto two lines when they don't fit their band (long date ranges).
+    let wraps = !horiz && c.categories.iter().any(|n| n.chars().count() as f64 * base * 0.5 > band);
     for (i, name) in c.categories.iter().enumerate() {
         let mid = if horiz { plot.y0 + band * (i as f64 + 0.5) } else { plot.x0 + band * (i as f64 + 0.5) };
         if horiz {
@@ -240,12 +363,13 @@ pub fn draw(ctx: &mut RenderContext, rctx: &Ctx, c: &Chart, m: Affine, w: f64, h
                 false,
             );
         } else {
+            let text = if wraps { split_label(name) } else { name.clone() };
             label(
                 ctx,
                 rctx,
                 m,
-                name,
-                Rect::new(mid - band / 2.0, plot.y1 + 3.0, mid + band / 2.0, plot.y1 + base * 1.6),
+                &text,
+                Rect::new(mid - band / 2.0, plot.y1 + 3.0, mid + band / 2.0, plot.y1 + base * if wraps { 2.8 } else { 1.6 }),
                 base,
                 Align::Center,
                 Anchor::Top,
@@ -254,24 +378,27 @@ pub fn draw(ctx: &mut RenderContext, rctx: &Ctx, c: &Chart, m: Affine, w: f64, h
             );
         }
     }
-    let ns = c.series.len().max(1);
     let zero = to_v(0.0f64.clamp(min, max));
-    if c.kind.is_bar_like() {
+    if let Some(bk) = bar_kind {
+        let bars: Vec<(usize, &deckcraft_model::chart::Series)> =
+            c.series.iter().enumerate().filter(|(_, s)| c.series_kind(s).is_bar_like()).collect();
+        let ns = bars.len().max(1);
         let gap = c.gap_width.clamp(0.0, 5.0);
         let group = band / (1.0 + gap);
-        let stacked = c.kind.stacked();
+        let stacked = bk.stacked();
         let bar = if stacked { group } else { group / ns as f64 };
         for i in 0..ncat {
             let mut pos_acc = 0.0;
             let mut neg_acc = 0.0;
-            let total: f64 = if c.kind.percent() {
-                c.series.iter().map(|s| s.values.get(i).copied().flatten().unwrap_or(0.0).abs()).sum::<f64>().max(1e-9)
+            let total: f64 = if bk.percent() {
+                bars.iter().map(|(_, s)| s.values.get(i).copied().flatten().unwrap_or(0.0).abs()).sum::<f64>().max(1e-9)
             } else {
                 1.0
             };
-            for (si, s) in c.series.iter().enumerate() {
+            for (bi, (si, s)) in bars.iter().enumerate() {
+                let sec = c.on_secondary(s);
                 let v = s.values.get(i).copied().flatten().unwrap_or(0.0) / total;
-                let start = band * i as f64 + (band - group) / 2.0 + if stacked { 0.0 } else { bar * si as f64 };
+                let start = band * i as f64 + (band - group) / 2.0 + if stacked { 0.0 } else { bar * bi as f64 };
                 let (a, b) = if stacked {
                     if v >= 0.0 {
                         let r = (pos_acc, pos_acc + v);
@@ -288,13 +415,13 @@ pub fn draw(ctx: &mut RenderContext, rctx: &Ctx, c: &Chart, m: Affine, w: f64, h
                 let r = if horiz {
                     Rect::new(to_v(a), plot.y0 + start, to_v(b), plot.y0 + start + bar)
                 } else {
-                    Rect::new(plot.x0 + start, to_v(b), plot.x0 + start + bar, to_v(a))
+                    Rect::new(plot.x0 + start, to_axis(sec, b), plot.x0 + start + bar, to_axis(sec, a))
                 };
                 ctx.set_transform(m);
-                ctx.set_paint(color(series_fill(rctx, c, si, Some(s)), 1.0));
+                ctx.set_paint(color(series_fill(rctx, c, *si, Some(s)), 1.0));
                 ctx.fill_rect(&r.abs());
                 if c.data_labels {
-                    let t = fmt_num(s.values.get(i).copied().flatten().unwrap_or(0.0));
+                    let t = c.data_label(s, s.values.get(i).copied().flatten().unwrap_or(0.0));
                     let lr = if horiz {
                         Rect::new(r.x1 + 2.0, r.y0, r.x1 + 40.0, r.y1)
                     } else {
@@ -315,66 +442,72 @@ pub fn draw(ctx: &mut RenderContext, rctx: &Ctx, c: &Chart, m: Affine, w: f64, h
                 }
             }
         }
-    } else {
-        // Lines, areas, scatter, radar (drawn as lines).
-        let stacked = c.kind.stacked();
-        let mut acc = vec![0.0; ncat];
-        for (si, s) in c.series.iter().enumerate() {
-            let col = series_fill(rctx, c, si, Some(s));
-            let mut pts = vec![];
-            for i in 0..ncat {
-                let Some(v) = s.values.get(i).copied().flatten() else { continue };
-                let v = if stacked {
-                    let base_v = acc.get(i).copied().unwrap_or(0.0);
-                    if let Some(a) = acc.get_mut(i) {
-                        *a += v;
-                    }
-                    base_v + v
-                } else {
-                    v
-                };
-                let x = match c.kind {
-                    ChartType::Scatter | ChartType::Bubble => {
-                        let xs: Vec<f64> = s.x_values.iter().flatten().copied().collect();
-                        let (xl, xh) = (xs.iter().copied().fold(f64::MAX, f64::min), xs.iter().copied().fold(f64::MIN, f64::max));
-                        let xv = s.x_values.get(i).copied().flatten().unwrap_or(i as f64);
-                        if xh > xl { plot.x0 + (xv - xl) / (xh - xl) * plot.width() } else { plot.x0 + band * (i as f64 + 0.5) }
-                    }
-                    _ => plot.x0 + band * (i as f64 + 0.5),
-                };
-                pts.push(Point::new(x, to_v(v)));
-            }
-            if pts.is_empty() {
-                continue;
-            }
-            let mut p = BezPath::new();
-            for (k, q) in pts.iter().enumerate() {
-                if k == 0 {
-                    p.move_to(*q);
-                } else {
-                    p.line_to(*q);
+    }
+    // Lines, areas, scatter, radar (drawn as lines): the series that aren't bars.
+    let mut acc = vec![0.0; ncat];
+    for (si, s) in c.series.iter().enumerate() {
+        let kind = c.series_kind(s);
+        if kind.is_bar_like() {
+            continue;
+        }
+        let sec = c.on_secondary(s);
+        let stacked = kind.stacked();
+        let area_kind = matches!(kind, ChartType::Area | ChartType::StackedArea | ChartType::FilledRadar);
+        let col = if area_kind { series_fill(rctx, c, si, Some(s)) } else { series_line(rctx, c, si, s) };
+        let mut pts = vec![];
+        for i in 0..ncat {
+            let Some(v) = s.values.get(i).copied().flatten() else { continue };
+            let v = if stacked {
+                let base_v = acc.get(i).copied().unwrap_or(0.0);
+                if let Some(a) = acc.get_mut(i) {
+                    *a += v;
                 }
-            }
-            ctx.set_transform(m);
-            if matches!(c.kind, ChartType::Area | ChartType::StackedArea | ChartType::FilledRadar) {
-                let mut a = p.clone();
-                if let (Some(l), Some(f)) = (pts.last(), pts.first()) {
-                    a.line_to((l.x, zero));
-                    a.line_to((f.x, zero));
-                    a.close_path();
+                base_v + v
+            } else {
+                v
+            };
+            let x = match kind {
+                ChartType::Scatter | ChartType::Bubble => {
+                    let xs: Vec<f64> = s.x_values.iter().flatten().copied().collect();
+                    let (xl, xh) = (xs.iter().copied().fold(f64::MAX, f64::min), xs.iter().copied().fold(f64::MIN, f64::max));
+                    let xv = s.x_values.get(i).copied().flatten().unwrap_or(i as f64);
+                    if xh > xl { plot.x0 + (xv - xl) / (xh - xl) * plot.width() } else { plot.x0 + band * (i as f64 + 0.5) }
                 }
-                ctx.set_paint(color(col, 0.85));
-                ctx.fill_path(&a);
-            } else if c.kind != ChartType::Scatter {
-                ctx.set_paint(color(col, 1.0));
-                ctx.set_stroke(kurbo::Stroke::new(2.25).with_join(kurbo::Join::Round).with_caps(kurbo::Cap::Round));
-                ctx.stroke_path(&p);
+                _ => plot.x0 + band * (i as f64 + 0.5),
+            };
+            pts.push(Point::new(x, to_axis(sec, v)));
+        }
+        if pts.is_empty() {
+            continue;
+        }
+        let mut p = BezPath::new();
+        for (k, q) in pts.iter().enumerate() {
+            if k == 0 {
+                p.move_to(*q);
+            } else {
+                p.line_to(*q);
             }
-            if matches!(c.kind, ChartType::LineMarkers | ChartType::Scatter | ChartType::Bubble) {
-                ctx.set_paint(color(col, 1.0));
-                for q in &pts {
-                    ctx.fill_path(&kurbo::Circle::new(*q, 3.5).to_path(0.1));
-                }
+        }
+        ctx.set_transform(m);
+        if area_kind {
+            let mut a = p.clone();
+            if let (Some(l), Some(f)) = (pts.last(), pts.first()) {
+                a.line_to((l.x, zero));
+                a.line_to((f.x, zero));
+                a.close_path();
+            }
+            ctx.set_paint(color(col, 0.85));
+            ctx.fill_path(&a);
+        } else if kind != ChartType::Scatter {
+            let lw = s.line.as_ref().and_then(|l| l.width).filter(|w| w.is_finite() && *w > 0.0).unwrap_or(2.25).clamp(0.25, 20.0);
+            ctx.set_paint(color(col, 1.0));
+            ctx.set_stroke(kurbo::Stroke::new(lw).with_join(kurbo::Join::Round).with_caps(kurbo::Cap::Round));
+            ctx.stroke_path(&p);
+        }
+        if matches!(kind, ChartType::LineMarkers | ChartType::Scatter | ChartType::Bubble) {
+            ctx.set_paint(color(col, 1.0));
+            for q in &pts {
+                ctx.fill_path(&kurbo::Circle::new(*q, 3.5).to_path(0.1));
             }
         }
     }
@@ -392,3 +525,40 @@ pub fn draw(ctx: &mut RenderContext, rctx: &Ctx, c: &Chart, m: Affine, w: f64, h
     ctx.set_stroke(kurbo::Stroke::new(0.75));
     ctx.stroke_path(&ax);
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    const AREA: Rect = Rect::new(0.0, 0.0, 400.0, 300.0);
+
+    #[test]
+    fn right_legend_is_a_centred_column_and_narrows_the_plot() {
+        let (o, plot) = legend_layout("r", (60.0, 100.0), AREA, 10.0, false);
+        assert_eq!((o.x, o.y), (340.0, 100.0));
+        assert_eq!((plot.x0, plot.x1, plot.y0, plot.y1), (0.0, 335.0, 0.0, 300.0));
+    }
+
+    #[test]
+    fn left_top_and_corner_positions() {
+        let (o, plot) = legend_layout("l", (60.0, 100.0), AREA, 10.0, false);
+        assert_eq!((o.x, o.y, plot.x0, plot.x1), (0.0, 100.0, 65.0, 400.0));
+        let (o, plot) = legend_layout("t", (100.0, 14.0), AREA, 10.0, false);
+        assert_eq!((o.x, o.y, plot.y0, plot.y1), (150.0, 0.0, 19.0, 300.0));
+        let (o, plot) = legend_layout("tr", (60.0, 100.0), AREA, 10.0, false);
+        assert_eq!((o.x, o.y, plot.x1), (340.0, 0.0, 335.0));
+    }
+
+    #[test]
+    fn bottom_legend_keeps_the_old_row_layout() {
+        let (o, plot) = legend_layout("b", (100.0, 14.0), AREA, 10.0, false);
+        assert_eq!((o.x, o.y, plot.y1, plot.x1), (150.0, 286.0, 281.0, 400.0));
+    }
+
+    #[test]
+    fn overlay_does_not_shrink_the_plot() {
+        let (o, plot) = legend_layout("r", (60.0, 100.0), AREA, 10.0, true);
+        assert_eq!(plot, AREA);
+        assert_eq!(o.x, 340.0);
+    }
+}

crates/render/src/images.rs

@@ -66,15 +66,17 @@ fn with<R>(f: impl FnOnce(&mut Cache) -> R) -> R {
 }
 
 fn adjust_key(a: &PictureAdjust) -> u64 {
-    let mut h: u64 = 1469598103934665603;
-    let mut mix = |v: u64| {
-        h ^= v;
-        h = h.wrapping_mul(1099511628211);
-    };
+    use std::hash::Hasher;
+    // A real hash: an FNV-style xor-multiply mix let (b, c) and (-b, -c) collide (the sign bits
+    // cancel), so a picture brightened and contrasted showed the darkened copy's pixels.
+    let mut hs = std::hash::DefaultHasher::new();
+    let mut mix = |v: u64| hs.write_u64(v);
     mix(a.brightness.to_bits());
     mix(a.contrast.to_bits());
     mix(a.saturation.unwrap_or(1.0).to_bits());
     mix(a.grayscale as u64);
+    mix(a.bilevel.map_or(u64::MAX, f64::to_bits));
+    mix(a.alpha_inv as u64);
     mix(a.sharpen.to_bits());
     if let Some(c) = a.clear_color {
         mix(((c.r as u64) << 16) | ((c.g as u64) << 8) | c.b as u64 | 1 << 40);
@@ -84,7 +86,7 @@ fn adjust_key(a: &PictureAdjust) -> u64 {
             mix(((c.r as u64) << 24) | ((c.g as u64) << 16) | ((c.b as u64) << 8) | c.a as u64 | 1 << 41);
         }
     }
-    h
+    hs.finish()
 }
 
 /// The duotone's dark and light colours. The painter resolves them to plain RGB first (see
@@ -121,6 +123,56 @@ fn decode_at(bytes: &[u8], side: u32) -> Option<image::RgbaImage> {
     Some(img.to_rgba8())
 }
 
+/// A raster picture's own size in 96-dpi pixels (so 0.75 pt each), read from its header: its
+/// pixel size, scaled by the resolution it records (PNG `pHYs`, JPEG JFIF density) when that
+/// isn't 96 dpi, as PowerPoint sizes pictures. `None` for metafiles and anything unreadable.
+pub fn natural_size(bytes: &[u8]) -> Option<(f64, f64)> {
+    if crate::metafile::is_metafile(bytes) {
+        return None;
+    }
+    let (w, h) = image::ImageReader::new(std::io::Cursor::new(bytes)).with_guessed_format().ok()?.into_dimensions().ok()?;
+    if w == 0 || h == 0 {
+        return None;
+    }
+    let (dx, dy) = dpi(bytes).unwrap_or((96.0, 96.0));
+    Some((w as f64 * 96.0 / dx, h as f64 * 96.0 / dy))
+}
+
+/// The resolution (whole dots per inch across and down) a PNG or JPEG records, when it records
+/// one in a plausible range.
+pub fn dpi(bytes: &[u8]) -> Option<(f64, f64)> {
+    // Whole dots per inch: PNGs store dots per metre, so 96 dpi reads as 95.9866.
+    let ok = |d: f64| (d.is_finite() && (10.0..=10000.0).contains(&d)).then_some(d.round());
+    let be32 = |b: &[u8], i: usize| b.get(i..i + 4).map(|s| u32::from_be_bytes([s[0], s[1], s[2], s[3]]));
+    let be16 = |b: &[u8], i: usize| b.get(i..i + 2).map(|s| u16::from_be_bytes([s[0], s[1]]));
+    if bytes.starts_with(b"\x89PNG\r\n\x1a\n") {
+        let mut i = 8usize;
+        for _ in 0..64 {
+            let len = be32(bytes, i)? as usize;
+            let kind = bytes.get(i + 4..i + 8)?;
+            if kind == b"pHYs" {
+                let (x, y, unit) = (be32(bytes, i + 8)?, be32(bytes, i + 12)?, *bytes.get(i + 16)?);
+                return if unit == 1 { Some((ok(x as f64 * 0.0254)?, ok(y as f64 * 0.0254)?)) } else { None };
+            }
+            if kind == b"IDAT" || kind == b"IEND" {
+                return None;
+            }
+            i = i.checked_add(12)?.checked_add(len)?;
+        }
+        return None;
+    }
+    if bytes.starts_with(&[0xFF, 0xD8]) && bytes.get(6..11) == Some(b"JFIF\0".as_slice()) {
+        let unit = *bytes.get(13)?;
+        let (x, y) = (be16(bytes, 14)? as f64, be16(bytes, 16)? as f64);
+        return match unit {
+            1 => Some((ok(x)?, ok(y)?)),
+            2 => Some((ok(x * 2.54)?, ok(y * 2.54)?)),
+            _ => None,
+        };
+    }
+    None
+}
+
 /// A premultiplied pixmap of the picture, downsampled so its longer side is near `want` px.
 pub fn decode_for(bytes: &Arc<Vec<u8>>, want: f64, adj: &PictureAdjust) -> Option<Arc<Pixmap>> {
     let addr = Arc::as_ptr(bytes) as usize;
@@ -256,7 +308,15 @@ pub(crate) fn gif_pixmap(bytes: &Arc<Vec<u8>>, adj: &PictureAdjust, t: f64) -> O
 
 fn apply_adjust(img: &mut image::RgbaImage, a: &PictureAdjust) {
     let sat = a.saturation.unwrap_or(1.0);
-    if a.brightness == 0.0 && a.contrast == 0.0 && sat == 1.0 && !a.grayscale && a.clear_color.is_none() && a.duotone.is_none() {
+    if a.brightness == 0.0
+        && a.contrast == 0.0
+        && sat == 1.0
+        && !a.grayscale
+        && a.clear_color.is_none()
+        && a.duotone.is_none()
+        && a.bilevel.is_none()
+        && !a.alpha_inv
+    {
         return;
     }
     let duo = duotone_rgb(a);
@@ -273,26 +333,43 @@ fn apply_adjust(img: &mut image::RgbaImage, a: &PictureAdjust) {
             continue;
         }
         let mut rgb = [p[0] as f64, p[1] as f64, p[2] as f64];
-        let y = 0.299 * rgb[0] + 0.587 * rgb[1] + 0.114 * rgb[2];
+        let y = luma(rgb);
         let s = if a.grayscale { 0.0 } else { sat };
         for v in &mut rgb {
             *v = y + (*v - y) * s;
-            *v = (*v - 128.0) * cf + 128.0 + b;
+            // Measured on PowerPoint's export of grey ramps: contrast scales about mid-grey by
+            // `cf`, and brightness adds b · 255 scaled by (1 + cf) / 2 (half of it is applied
+            // before the contrast stretch, half after): +40% bright, +40% contrast maps 0 to 54.
+            *v = (*v - 127.5) * cf + 127.5 + b * (1.0 + cf) / 2.0;
         }
         // Duotone: the pixel's luminance picks a colour between the dark and the light one.
         if let Some((d, l)) = duo {
-            let t = ((0.299 * rgb[0] + 0.587 * rgb[1] + 0.114 * rgb[2]) / 255.0).clamp(0.0, 1.0);
+            let t = (luma(rgb) / 255.0).clamp(0.0, 1.0);
             rgb =
                 [d.r as f64 + (l.r as f64 - d.r as f64) * t, d.g as f64 + (l.g as f64 - d.g as f64) * t, d.b as f64 + (l.b as f64 - d.b as f64) * t];
         }
+        // Black and white: white where the luminance reaches the threshold.
+        if let Some(t) = a.bilevel {
+            let v = if luma(rgb) >= t * 255.0 { 255.0 } else { 0.0 };
+            rgb = [v; 3];
+        }
         for (i, v) in rgb.iter().enumerate() {
             if let Some(ch) = p.0.get_mut(i) {
                 *ch = v.round().clamp(0.0, 255.0) as u8;
             }
         }
+        if a.alpha_inv {
+            p[3] = 255 - p[3];
+        }
     }
 }
 
+/// Luminance as PowerPoint weighs it for grayscale, black-and-white and duotone pictures
+/// (measured: Rec. 709 weights on the stored values; pure red greys to 54, green to 182).
+fn luma(rgb: [f64; 3]) -> f64 {
+    0.2126 * rgb[0] + 0.7152 * rgb[1] + 0.0722 * rgb[2]
+}
+
 #[cfg(test)]
 mod tests {
     #![allow(clippy::expect_used)]
@@ -318,6 +395,58 @@ mod tests {
         assert_ne!(adjust_key(&adj), adjust_key(&PictureAdjust::default()));
     }
 
+    #[test]
+    fn brightness_and_contrast_map_greys_like_powerpoint() {
+        // Grey levels PowerPoint's export gives for inputs 0, 32, 64, 96 (and 128, 160).
+        let run = |b: f64, c: f64, input: &[u8]| -> Vec<u8> {
+            let mut img = image::RgbaImage::from_fn(input.len() as u32, 1, |x, _| {
+                let v = input[x as usize];
+                image::Rgba([v, v, v, 255])
+            });
+            apply_adjust(&mut img, &PictureAdjust { brightness: b, contrast: c, ..Default::default() });
+            img.pixels().map(|p| p[0]).collect()
+        };
+        let near = |got: Vec<u8>, want: &[u8]| got.iter().zip(want).all(|(g, w)| (*g as i32 - *w as i32).abs() <= 5);
+        assert!(near(run(0.4, 0.4, &[0, 32, 64, 96]), &[54, 105, 157, 210]), "{:?}", run(0.4, 0.4, &[0, 32, 64, 96]));
+        assert!(near(run(0.4, -0.4, &[0, 32, 64, 96]), &[133, 152, 171, 190]));
+        assert!(near(run(-0.4, 0.4, &[128, 160, 192]), &[0, 45, 97]));
+        assert!(near(run(0.0, -0.8, &[0, 128, 255]), &[102, 127, 152]));
+    }
+
+    #[test]
+    fn grayscale_black_and_white_and_inverted_alpha_like_powerpoint() {
+        let swatches = [[255u8, 0, 0], [0, 255, 0], [0, 0, 255], [200, 100, 50], [60, 160, 110], [120, 120, 130]];
+        let run = |adj: PictureAdjust| -> Vec<[u8; 4]> {
+            let mut img = image::RgbaImage::from_fn(swatches.len() as u32, 1, |x, _| {
+                let c = swatches[x as usize];
+                image::Rgba([c[0], c[1], c[2], 200])
+            });
+            apply_adjust(&mut img, &adj);
+            img.pixels().map(|p| p.0).collect()
+        };
+        // PowerPoint's export of these swatches in grayscale: 54, 182, 18, 117, 135, 120.
+        let g = run(PictureAdjust { grayscale: true, ..Default::default() });
+        for (got, want) in g.iter().zip([54u8, 182, 18, 117, 135, 120]) {
+            assert!((got[0] as i32 - want as i32).abs() <= 1 && got[0] == got[1] && got[1] == got[2], "{got:?} vs {want}");
+        }
+        // Black and white at 50%: only green and the light green reach mid-grey.
+        let bw: Vec<u8> = run(PictureAdjust { bilevel: Some(0.5), ..Default::default() }).iter().map(|p| p[0]).collect();
+        assert_eq!(bw, [0, 255, 0, 0, 255, 0]);
+        // Inverted alpha: 200 becomes 55.
+        assert!(run(PictureAdjust { alpha_inv: true, ..Default::default() }).iter().all(|p| p[3] == 55));
+    }
+
+    #[test]
+    fn opposite_brightness_and_contrast_are_cached_apart() {
+        let a = PictureAdjust { brightness: 0.4, contrast: 0.4, ..Default::default() };
+        let b = PictureAdjust { brightness: -0.4, contrast: -0.4, ..Default::default() };
+        assert_ne!(adjust_key(&a), adjust_key(&b));
+        let c = PictureAdjust { brightness: 0.4, contrast: -0.4, ..Default::default() };
+        let d = PictureAdjust { brightness: -0.4, contrast: 0.4, ..Default::default() };
+        assert_ne!(adjust_key(&c), adjust_key(&d));
+        assert_eq!(adjust_key(&a), adjust_key(&a.clone()));
+    }
+
     #[test]
     fn a_gif_of_many_tiny_frames_keeps_only_the_frame_cap() {
         use image::{Delay, Frame, Rgba, RgbaImage};

crates/render/src/lib.rs

@@ -7,6 +7,8 @@
 #![deny(clippy::unwrap_used, clippy::expect_used, clippy::panic, clippy::unimplemented, clippy::todo, clippy::unreachable)]
 #![forbid(unsafe_code)]
 
+mod bevel;
+mod camera;
 mod chart;
 mod colr;
 
@@ -23,6 +25,7 @@ mod pathgrad;
 mod placed;
 mod ramp;
 mod table;
+mod transition;
 mod warp;
 
 use std::collections::HashMap;
@@ -41,12 +44,14 @@ use kurbo::{Affine, BezPath, PathEl, Point, Rect, Shape as _, Vec2};
 use vello_common::filter_effects::{EdgeMode, Filter, FilterPrimitive};
 use vello_cpu::{RenderContext, Resources, peniko};
 
+pub use deckcraft_anim::{transition_frame, transition_layers, uses_slide_parts};
 pub use extent::{Region, TILE, layout_extent, pasteboard_region, slide_extent};
 pub use images::{decode as decode_image, gif_frame};
 pub use morph_path::PathMorph;
 pub use morph_text::TextMorph;
 pub use placed::{Placed, PlacedLink, PlacedText, place_slide};
 pub use table::row_heights as table_row_heights;
+pub use transition::{SlideParts, composite_transition, render_transition};
 
 /// Largest pixmap side we render (vello_cpu uses u16 sizes).
 pub const MAX_SIDE: u32 = 16_000;
@@ -241,11 +246,14 @@ pub struct Renderer {
     /// The transform a top-level shape is drawn under (slide to pixels); a group's children draw
     /// under it combined with the group's child-coordinate mapping, which must not scale lines.
     view: Affine,
+    /// The fill of the group being drawn, with the transform and box it is laid out in: children
+    /// filled with the group's fill (`a:grpFill`) show it, as one fill across the whole group.
+    group_fill: Option<(Fill, Affine, Rect)>,
 }
 
 impl Default for Renderer {
     fn default() -> Self {
-        Renderer { resources: Resources::new(), paths: Vec::new(), bg: None, drawn: None, view: Affine::IDENTITY }
+        Renderer { resources: Resources::new(), paths: Vec::new(), bg: None, drawn: None, view: Affine::IDENTITY, group_fill: None }
     }
 }
 
@@ -329,6 +337,30 @@ pub fn render_slide_drawn(pres: &Presentation, index: usize, opts: &RenderOpts)
     }
 }
 
+/// Which part of a slide [`render_slide_part`] draws.
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+pub enum SlidePart {
+    /// The background fill with the master and layout graphics.
+    Backdrop,
+    /// The slide's own shapes over transparency.
+    Content,
+}
+
+/// Render one part of slide `index` (transitions that move the contents over the backgrounds).
+/// A panic inside the renderer becomes a transparent image (logged), never a crash.
+pub fn render_slide_part(pres: &Presentation, index: usize, part: SlidePart, opts: &RenderOpts) -> Image {
+    let Some(slide) = pres.slides.get(index) else { return Image::default() };
+    match std::panic::catch_unwind(std::panic::AssertUnwindSafe(|| RENDERER.with(|r| r.borrow_mut().slide_part(pres, slide, index, part, opts)))) {
+        Ok(img) => img,
+        Err(_) => {
+            log::error!("rendering part of slide {index} panicked; showing nothing");
+            RENDERER.with(|r| *r.borrow_mut() = Renderer::default());
+            let (w, h) = output_size(pres, opts);
+            Image { width: w as u32, height: h as u32, pixels: vec![0; w as usize * h as usize * 4] }
+        }
+    }
+}
+
 /// Render a frame between slides `old` and `new` (indices into `pres.slides`), e.g. of Morph: the
 /// backdrop (background, master and layout graphics) of `old` cross-fading into that of `new` by
 /// `mix` (0..1), then `shapes` in order, each resolved against the slide it comes from (`true`:
@@ -408,7 +440,9 @@ pub fn shape_geometry(shape: &Shape, w: f64, h: f64) -> Geometry {
                 let (pw, ph) = (if p.w > 0.0 { p.w } else { w.max(1e-9) }, if p.h > 0.0 { p.h } else { h.max(1e-9) });
                 let mut bp = parse_path(&p.d);
                 bp.apply_affine(Affine::scale_non_uniform(w / pw, h / ph));
-                out.push(SubPath { path: bp, fill: p.fill, stroke: p.stroke, even_odd: false });
+                // PowerPoint fills each custom path's sub-paths alternately (even-odd): a sub-path
+                // inside another cuts a hole whichever way it winds, as in icons and outlined text.
+                out.push(SubPath { path: bp, fill: p.fill, stroke: p.stroke, even_odd: true });
             }
             Geometry { paths: out, text_rect: Rect::new(0.0, 0.0, w, h), handles: vec![], sites: vec![] }
         }
@@ -550,6 +584,25 @@ impl Renderer {
         self.finish(ctx, w, h)
     }
 
+    fn slide_part(&mut self, pres: &Presentation, slide: &Slide, index: usize, part: SlidePart, opts: &RenderOpts) -> Image {
+        let (mut ctx, w, h, view) = Self::canvas(pres, opts, needs_filters(pres, slide));
+        let f = Frame { pres, opts, fields: Self::fields(pres, index, opts) };
+        if let Some(rctx) = Ctx::for_slide(pres, slide) {
+            match part {
+                SlidePart::Backdrop => self.backdrop(&mut ctx, &f, &rctx, slide, view),
+                SlidePart::Content => {
+                    // Shapes filled with the background (`useBgFill`) still show it.
+                    let (fill, ph) = resolve::background(&rctx, Some(slide));
+                    self.bg = Some((fill, ph, view));
+                    for s in &slide.shapes {
+                        self.shape(&mut ctx, &f, &rctx, s, view, 0);
+                    }
+                }
+            }
+        }
+        self.finish(ctx, w, h)
+    }
+
     #[allow(clippy::too_many_arguments)]
     fn blend(
         &mut self,
@@ -681,6 +734,24 @@ impl Renderer {
         if depth > 0 && view.determinant().abs() > 1e-12 && view.is_finite() { (view, view.inverse() * m) } else { (m, Affine::IDENTITY) }
     }
 
+    /// The size and transform a shape's text is set in: inside a group whose child coordinates
+    /// scale the shape, the shape's size in slide points and `m` with that scale taken out, so
+    /// insets and font sizes stay in points; otherwise `w`, `h` and `m` themselves.
+    fn text_space(&self, m: Affine, depth: usize, w: f64, h: f64) -> (f64, f64, Affine) {
+        let (_, rel) = self.line_space(m, depth);
+        let c = rel.as_coeffs();
+        let (sx, sy) = (c[0].hypot(c[1]), c[2].hypot(c[3]));
+        let ok = |k: f64| k.is_finite() && k > 1e-9;
+        if depth == 0 || !ok(sx) || !ok(sy) || ((sx - 1.0).abs() < 1e-9 && (sy - 1.0).abs() < 1e-9) {
+            return (w, h, m);
+        }
+        let (tw, th) = (w * sx, h * sy);
+        if !tw.is_finite() || !th.is_finite() {
+            return (w, h, m);
+        }
+        (tw, th, m * Affine::scale_non_uniform(1.0 / sx, 1.0 / sy))
+    }
+
     fn shape_at(&mut self, ctx: &mut RenderContext, f: &Frame, rctx: &Ctx, s: &Shape, parent: Affine, depth: usize) {
         if depth > 32 || (s.hidden && !f.opts.show_hidden) || f.opts.skip.contains(&s.id) {
             return;
@@ -703,6 +774,17 @@ impl Renderer {
                 * Affine::translate(-c.to_vec2());
             m = parent * Affine::translate(st.offset) * x.affine() * around;
         }
+        // A 3-D camera turns the shape (approximated by the affine transform that fits it best).
+        if !matches!(s.kind, ShapeKind::Group { .. } | ShapeKind::Table(_) | ShapeKind::Chart(_))
+            && let Some(a) = resolve::effects(rctx, s)
+                .0
+                .as_ref()
+                .and_then(|e| e.raw3d.as_deref())
+                .and_then(camera::from_raw)
+                .and_then(|c| camera::affine(&c, x.w, x.h))
+        {
+            m *= a;
+        }
         let layered = st.opacity < 0.999 || st.clip.is_some();
         if layered {
             ctx.set_transform(m);
@@ -713,9 +795,43 @@ impl Renderer {
             ShapeKind::Group { children, child } => {
                 let ch = Rect::new(child.x, child.y, child.x + child.w, child.y + child.h);
                 let gm = parent * deckcraft_geom::group_child_affine(&x, ch);
+                // A group's own fill (a group filled with its parent's passes that on).
+                let own = match &s.fill {
+                    Some(Fill::Group) | None => self.group_fill.clone(),
+                    Some(fl) => Some((fl.clone(), m, Rect::new(0.0, 0.0, x.w, x.h))),
+                };
+                let outer = std::mem::replace(&mut self.group_fill, own);
+                // A group's outer shadow is cast by everything in it, as PowerPoint draws it: the
+                // children drawn once more under the shadow's offset, scale and skew, recoloured to
+                // the shadow colour and blurred, below the group.
+                if let Some(sh) = s.effects.as_ref().and_then(|e| e.outer_shadow.as_ref()) {
+                    let c = rctx.color(&sh.color, None);
+                    let k = scale_of(m);
+                    let d = Vec2::new(sh.dir.to_radians().cos(), sh.dir.to_radians().sin()) * sh.dist;
+                    let local = shadow_local(sh, x.w, x.h);
+                    let (own, pre) =
+                        if sh.rotate_with_shape { (Affine::translate(d) * local, Affine::IDENTITY) } else { (local, Affine::translate(d * k)) };
+                    let det = m.determinant();
+                    if det.is_finite() && det.abs() > 1e-12 {
+                        let shift = pre * m * own * m.inverse();
+                        ctx.set_transform(Affine::IDENTITY);
+                        ctx.push_layer(None, None, Some((c.a as f32) / 255.0), None, Some(blur(sh.blur / 3.0 * k)));
+                        for ch in children {
+                            self.shape(ctx, f, rctx, ch, shift * gm, depth + 1);
+                        }
+                        ctx.set_transform(Affine::IDENTITY);
+                        ctx.push_layer(None, Some(peniko::BlendMode::new(peniko::Mix::Normal, peniko::Compose::SrcIn)), None, None, None);
+                        ctx.set_paint(color(c.with_alpha(255), 1.0));
+                        let (w, h) = (f.opts.scale * f.pres.slide_size.width, f.opts.scale * f.pres.slide_size.height);
+                        ctx.fill_rect(&Rect::new(-w, -h, 3.0 * w, 3.0 * h).inflate(1e4, 1e4));
+                        ctx.pop_layer();
+                        ctx.pop_layer();
+                    }
+                }
                 for c in children {
                     self.shape(ctx, f, rctx, c, gm, depth + 1);
                 }
+                self.group_fill = outer;
             }
             ShapeKind::Table(t) => {
                 // Rows grow with their text: what the cells cover, borders included.
@@ -785,7 +901,24 @@ impl Renderer {
         let fill = if let Some(t) = st.tint { Some(Fill::solid(deckcraft_model::ColorRef::rgb(t))) } else { fill };
         // Effects below the shape.
         if let Some(e) = &effects {
-            self.effects_below(ctx, rctx, e, fx_ph, &geo, &fill, m, w, h);
+            // A picture (or picture fill) casts its shadow from its pixels, not its frame.
+            let content = match (&s.kind, &fill) {
+                (ShapeKind::Picture { fill: pf }, _) | (_, Some(Fill::Picture(pf))) => Some(paint::resolved(rctx, pf, None).into_owned()),
+                _ => None,
+            };
+            // What casts the shadow: the fill as see-through as it is, and the outline.
+            let fill_alpha = fill_opacity(rctx, &fill, fill_ph);
+            let outline = line.fill.as_ref().filter(|f| !f.is_none()).map(|lf| {
+                let a = match lf {
+                    Fill::Solid { color: c } => rctx.color(c, line_ph).a as f64 / 255.0,
+                    _ => 1.0,
+                };
+                let (base, rel) = self.line_space(m, depth);
+                let lw = line.width.unwrap_or(0.75).max(0.0);
+                let outside = if border_outside(is_pic, effects.as_ref()) { outside_line(&line, lw) } else { None };
+                Caster { line: outside.map_or(std::borrow::Cow::Borrowed(&line), std::borrow::Cow::Owned), ph: line_ph, alpha: a, base, rel }
+            });
+            self.effects_below(ctx, rctx, e, fx_ph, &geo, &fill, fill_alpha, outline, content.as_ref(), m, w, h);
         }
         let soft = effects.as_ref().and_then(|e| e.soft_edge).filter(|r| *r > 0.0);
         if let Some(r) = soft {
@@ -842,6 +975,15 @@ impl Renderer {
                                 let path = (view.inverse() * m) * sp.path.clone();
                                 paint::fill_path(ctx, rctx, bg, *ph, &path, slide, *view, sp.fill, fade(i).fill, f.pres);
                             }
+                            // `grpFill`: the group's fill, laid out over the whole group.
+                            (Fill::Group, _) => {
+                                if let Some((gf, gm, gbox)) = &self.group_fill
+                                    && gm.determinant().abs() > 1e-12
+                                {
+                                    let path = (gm.inverse() * m) * sp.path.clone();
+                                    paint::fill_path(ctx, rctx, gf, None, &path, *gbox, *gm, sp.fill, fade(i).fill, f.pres);
+                                }
+                            }
                             _ => paint::fill_path(ctx, rctx, fl, fill_ph, &sp.path, Rect::new(0.0, 0.0, w, h), m, sp.fill, fade(i).fill, f.pres),
                         }
                         ctx.set_fill_rule(peniko::Fill::NonZero);
@@ -849,23 +991,120 @@ impl Renderer {
                 }
             }
         }
+        // `a:fillOverlay`: a fill blended over the shape's fill (PowerPoint's "Flow" themes multiply
+        // a gradient over a tiled picture), inside the filled outline, under the line.
+        if let Some(ov) = effects.as_ref().and_then(|e| e.fill_overlay.as_ref())
+            && fill.as_ref().is_some_and(|f| !f.is_none())
+        {
+            let mix = match ov.blend.as_str() {
+                "mult" => peniko::Mix::Multiply,
+                "screen" => peniko::Mix::Screen,
+                "darken" => peniko::Mix::Darken,
+                "lighten" => peniko::Mix::Lighten,
+                _ => peniko::Mix::Normal,
+            };
+            for (i, sp) in geo.paths.iter().enumerate().filter(|(i, sp)| sp.fill != FillMode::None && fade(*i).fill > 0.0) {
+                ctx.set_transform(m);
+                ctx.push_layer(Some(&sp.path), Some(peniko::BlendMode::new(mix, peniko::Compose::SrcOver)), None, None, None);
+                paint::fill_path(ctx, rctx, &ov.fill, fx_ph, &sp.path, Rect::new(0.0, 0.0, w, h), m, FillMode::Norm, fade(i).fill, f.pres);
+                ctx.pop_layer();
+            }
+        }
+        // Some presets' outlines default to sharp corners (PowerPoint's own per-shape default).
+        let line = match (&s.geom, line.join) {
+            (Geom::Preset { name, .. }, None) if preset::mitred_by_default(name) => {
+                Line { join: Some(deckcraft_model::style::LineJoin::Miter), ..line }
+            }
+            _ => line,
+        };
+        // A 3-D bevel: the face and a band inside the outline lit as surfaces.
+        if let Some(bv) = effects.as_ref().and_then(|e| e.raw3d.as_deref()).and_then(bevel::from_raw) {
+            let solid = match &fill {
+                Some(Fill::Solid { color: c }) => Some(rctx.color(c, fill_ph)),
+                _ => None,
+            };
+            let filled = is_pic || fill.as_ref().is_some_and(|f| !f.is_none());
+            if filled {
+                let mut area = BezPath::new();
+                for sp in geo.paths.iter().filter(|sp| sp.fill != FillMode::None) {
+                    area.extend(sp.path.iter());
+                }
+                if is_pic || area.elements().is_empty() {
+                    area = outline.clone();
+                }
+                bevel::draw(ctx, &bv, if is_pic { None } else { solid }, &area, Rect::new(0.0, 0.0, w, h), m, 1.0);
+            }
+        }
         // Outline.
         if line.fill.as_ref().is_some_and(|f| !f.is_none()) {
             let lw = line.width.unwrap_or(0.75).max(0.0);
             let (base, rel) = self.line_space(m, depth);
+            // Arrowheads go on lines, arcs and open freeforms (filled or not), never on closed
+            // outlines or on presets like brackets.
+            let ends = s.is_line()
+                || geo.is_open()
+                || (matches!(s.geom, Geom::Custom { .. })
+                    && geo.paths.iter().find(|p| p.stroke).is_some_and(|p| !p.path.elements().iter().any(|e| matches!(e, PathEl::ClosePath))));
+            let trims = if ends { head_trims(&line, lw) } else { (0.0, 0.0) };
+            let has_heads = ends && [&line.head, &line.tail].iter().any(|e| e.as_ref().is_some_and(|e| e.kind != "none"));
+            // A see-through line and its arrowheads are one shape in PowerPoint: drawn opaque into
+            // a layer that is then faded, so they don't darken where they meet.
+            let see_through = match &line.fill {
+                Some(Fill::Solid { color: c }) if has_heads => Some(rctx.color(c, line_ph)).filter(|c| c.a < 255),
+                _ => None,
+            };
+            let line = match see_through {
+                Some(c) => {
+                    ctx.set_transform(Affine::IDENTITY);
+                    ctx.push_layer(None, None, Some(c.a as f32 / 255.0), None, None);
+                    std::borrow::Cow::Owned(Line {
+                        fill: Some(Fill::solid(deckcraft_model::style::ColorRef::rgb(c.with_alpha(255)))),
+                        ..line.clone()
+                    })
+                }
+                None => std::borrow::Cow::Borrowed(&line),
+            };
+            // A picture's border lies outside the picture, as PowerPoint draws it: stroked twice
+            // as wide, outside the outline only (see `border_outside`).
+            let outside = border_outside(is_pic, effects.as_ref()).then(|| outside_line(&line, lw)).flatten();
+            let clipped = outside.is_some();
+            let (line, lw) = match outside {
+                Some(o) => {
+                    let mut clip = Rect::new(0.0, 0.0, w, h).inflate(w + h + lw * 8.0, w + h + lw * 8.0).to_path(0.1);
+                    clip.extend(outline.iter());
+                    ctx.set_transform(m);
+                    ctx.set_fill_rule(peniko::Fill::EvenOdd);
+                    ctx.push_clip_layer(&clip);
+                    ctx.set_fill_rule(peniko::Fill::NonZero);
+                    (std::borrow::Cow::Owned(o), lw * 2.0)
+                }
+                None => (line, lw),
+            };
+            let first_stroked = geo.paths.iter().position(|p| p.stroke);
             for (i, sp) in geo.paths.iter().enumerate().filter(|(i, p)| p.stroke && fade(*i).stroke > 0.0) {
-                let path = if rel == Affine::IDENTITY {
+                let mut path = if rel == Affine::IDENTITY {
                     std::borrow::Cow::Borrowed(&sp.path)
                 } else {
                     let mut moved = sp.path.clone();
                     moved.apply_affine(rel);
                     std::borrow::Cow::Owned(moved)
                 };
-                stroke(ctx, rctx, &line, line_ph, &path, base, lw, fade(i).stroke);
+                // The line stops inside its arrowheads, so a wide line doesn't poke out of them.
+                let whole = path.clone();
+                if Some(i) == first_stroked && trims != (0.0, 0.0) {
+                    path = std::borrow::Cow::Owned(trim_ends(&path, trims.0, trims.1));
+                }
+                stroke(ctx, rctx, &line, line_ph, &path, Some(&whole), base, lw, fade(i).stroke);
             }
-            if s.is_line() || geo.is_open() {
+            if ends {
                 arrowheads(ctx, rctx, &line, line_ph, &geo, rel, base, lw);
             }
+            if clipped {
+                ctx.pop_layer();
+            }
+            if see_through.is_some() {
+                ctx.pop_layer();
+            }
         }
         if let Some(r) = soft {
             // Feather: the shape (fill and line) fades to nothing at its outline. Measured on
@@ -916,6 +1155,16 @@ impl Renderer {
         if let Some(body) = &s.text
             && !skip_text
         {
+            // Text in a group is set at the shape's size on the slide, in points: a group's
+            // child-coordinate scale sizes and places the box, never the type (#233's twin).
+            let (tw, th, m) = self.text_space(m, depth, w, h);
+            let text_geo;
+            let geo = if (tw, th) == (w, h) {
+                &geo
+            } else {
+                text_geo = shape_geometry(s, tw, th);
+                &text_geo
+            };
             let tr = geo.text_rect;
             if !body.is_empty() {
                 let l = deckcraft_text::layout(rctx, s, body, &Opts { rect: tr, fields: &f.fields, prompt_color: None, no_shrink: false });
@@ -959,6 +1208,9 @@ impl Renderer {
         ph: Option<Rgba>,
         geo: &Geometry,
         fill: &Option<Fill>,
+        fill_alpha: Option<f64>,
+        outline: Option<Caster>,
+        content: Option<&deckcraft_model::style::PictureFill>,
         m: Affine,
         w: f64,
         h: f64,
@@ -976,18 +1228,53 @@ impl Renderer {
         if let Some(sh) = &e.outer_shadow {
             let c = rctx.color(&sh.color, ph);
             let d = Vec2::new(sh.dir.to_radians().cos(), sh.dir.to_radians().sin()) * sh.dist;
-            let c0 = Point::new(w / 2.0, h / 2.0);
-            let local = Affine::translate(c0.to_vec2())
-                * Affine::new([sh.sx, sh.ky.to_radians().tan(), sh.kx.to_radians().tan(), sh.sy, 0.0, 0.0])
-                * Affine::translate(-c0.to_vec2());
+            let local = shadow_local(sh, w, h);
             // Shadow offset is in slide space (doesn't rotate with the shape unless asked).
-            let sm = if sh.rotate_with_shape { m * Affine::translate(d) * local } else { pre_translate(m, d * k) * local };
+            let (own, pre) = if sh.rotate_with_shape { (Affine::translate(d) * local, Affine::IDENTITY) } else { (local, Affine::translate(d * k)) };
+            let sm = pre * m * own;
             ctx.set_transform(Affine::IDENTITY);
             // Blurred by a third of the blur radius, as PowerPoint's export shows.
             ctx.push_layer(None, None, Some((c.a as f32) / 255.0), None, Some(blur(sh.blur / 3.0 * k)));
             ctx.set_transform(sm);
-            ctx.set_paint(color(c.with_alpha(255), 1.0));
-            ctx.fill_path(&silhouette);
+            match content {
+                // As PowerPoint draws it: the shadow is the picture's own coverage (a logo on a
+                // transparent background casts the logo's shadow): the picture, clipped to the
+                // shape, recoloured to the shadow colour.
+                Some(pf) => {
+                    ctx.push_clip_layer(&silhouette);
+                    paint::picture(ctx, rctx.pres, pf, Rect::new(0.0, 0.0, w, h), sm, None);
+                    // Drawing the picture leaves its own pixel transform set: back to the shape's,
+                    // or the recolouring below covers only part of a large picture's shadow.
+                    ctx.set_transform(sm);
+                    ctx.push_layer(None, Some(peniko::BlendMode::new(peniko::Mix::Normal, peniko::Compose::SrcIn)), None, None, None);
+                    ctx.set_paint(color(c.with_alpha(255), 1.0));
+                    ctx.fill_rect(&Rect::new(0.0, 0.0, w, h).inflate(1.0, 1.0));
+                    ctx.pop_layer();
+                    ctx.pop_layer();
+                }
+                // The shadow is cast by what is drawn, as PowerPoint casts it: the filled part as
+                // see-through as its fill (none for an outline-only shape) …
+                None => {
+                    if let Some(a) = fill_alpha {
+                        let mut filled = BezPath::new();
+                        for sp in geo.paths.iter().filter(|sp| sp.fill != FillMode::None) {
+                            filled.extend(sp.path.iter());
+                        }
+                        ctx.set_paint(color(c.with_alpha(255), a));
+                        ctx.fill_path(&filled);
+                    }
+                }
+            }
+            // … and the outline (a picture's border too).
+            if let Some(o) = &outline {
+                let cast = Line { fill: Some(Fill::solid(deckcraft_model::style::ColorRef::rgb(c.with_alpha(255)))), ..o.line.as_ref().clone() };
+                let lw = o.line.width.unwrap_or(0.75).max(0.0);
+                for sp in geo.paths.iter().filter(|sp| sp.stroke) {
+                    let mut path = sp.path.clone();
+                    path.apply_affine(o.rel * own);
+                    stroke(ctx, rctx, &cast, o.ph, &path, None, pre * o.base, lw, o.alpha);
+                }
+            }
             ctx.pop_layer();
         }
         if let Some(g) = &e.glow {
@@ -1009,9 +1296,20 @@ impl Renderer {
             ctx.set_transform(Affine::IDENTITY);
             ctx.push_layer(None, None, Some(rf.start_alpha.clamp(0.0, 1.0) as f32 * 0.6), None, Some(blur(rf.blur * 0.5 * k)));
             ctx.set_transform(mm);
-            if let Some(fl) = fill {
-                paint::fill_path(ctx, rctx, fl, ph, &silhouette, Rect::new(0.0, 0.0, w, h), mm, FillMode::Norm, 1.0, rctx.pres);
+            match content {
+                // A picture reflects its pixels (it has no fill of its own).
+                Some(pf) => {
+                    ctx.push_clip_layer(&silhouette);
+                    paint::picture(ctx, rctx.pres, pf, Rect::new(0.0, 0.0, w, h), mm, None);
+                    ctx.pop_layer();
+                }
+                None => {
+                    if let Some(fl) = fill {
+                        paint::fill_path(ctx, rctx, fl, ph, &silhouette, Rect::new(0.0, 0.0, w, h), mm, FillMode::Norm, 1.0, rctx.pres);
+                    }
+                }
             }
+            ctx.set_transform(mm);
             // Fade mask.
             ctx.push_layer(None, Some(peniko::BlendMode::new(peniko::Mix::Normal, peniko::Compose::DestIn)), None, None, None);
             let grad = peniko::Gradient::new_linear(Point::new(0.0, h), Point::new(0.0, h * (1.0 - rf.end_pos.clamp(0.01, 1.0))))
@@ -1024,6 +1322,78 @@ impl Renderer {
     }
 }
 
+/// Whether a shape's border is drawn outside its outline: a picture's is, unless the picture is
+/// drawn in 3-D (a bevel seen through a 3-D scene), where PowerPoint centres it on the edge as on
+/// any shape (observed: an 18 pt border covers 9 pt of the picture then).
+fn border_outside(is_pic: bool, effects: Option<&Effects>) -> bool {
+    is_pic && !effects.is_some_and(|e| e.bevel.is_some() && e.raw3d.as_deref().is_some_and(|r| r.contains("scene3d")))
+}
+
+/// The line that draws `line` (`lw` wide) outside a picture: twice as wide, so the half outside
+/// the outline is the border, with dashes kept their length. `None` for compound lines, whose
+/// bands would not survive the doubling (they stay centred on the outline).
+fn outside_line(line: &Line, lw: f64) -> Option<Line> {
+    if line.compound.is_some_and(|c| c != deckcraft_model::style::Compound::Single) {
+        return None;
+    }
+    let dash = line.dash.as_ref().map(|d| {
+        let p = d.pattern();
+        deckcraft_model::style::Dash::Custom {
+            pattern: p.chunks(2).map(|c| (c.first().copied().unwrap_or(0.0) / 2.0, c.get(1).copied().unwrap_or(0.0) / 2.0)).collect(),
+        }
+    });
+    Some(Line { width: Some(lw * 2.0), dash: dash.or_else(|| line.dash.clone()), ..line.clone() })
+}
+
+/// A shape's outline as it casts a shadow: its line, that line's placeholder colour and opacity,
+/// and the space it is stroked in (see `Renderer::line_space`).
+struct Caster<'a> {
+    line: std::borrow::Cow<'a, Line>,
+    ph: Option<Rgba>,
+    alpha: f64,
+    base: Affine,
+    rel: Affine,
+}
+
+/// How opaque a fill is overall (`None` when nothing is filled): a solid colour's alpha, a
+/// gradient's mean stop alpha, otherwise opaque.
+fn fill_opacity(rctx: &Ctx, fill: &Option<Fill>, ph: Option<Rgba>) -> Option<f64> {
+    match fill {
+        None | Some(Fill::None) => None,
+        Some(Fill::Solid { color: c }) => Some(rctx.color(c, ph).a as f64 / 255.0),
+        Some(Fill::Gradient(g)) if !g.stops.is_empty() => {
+            Some(g.stops.iter().map(|s| rctx.color(&s.color, ph).a as f64 / 255.0).sum::<f64>() / g.stops.len() as f64)
+        }
+        Some(_) => Some(1.0),
+    }
+}
+
+/// A shadow's own scale and skew (`sx`, `sy`, `kx`, `ky`) in the shape's space, about the point
+/// of the shape's box its alignment names (`algn`: `b` is the middle of the bottom edge, `tl` the
+/// top-left corner…), as PowerPoint applies them: skewed, then scaled. A perspective shadow
+/// (`algn="b"`, `sy` 23%, `kx` -20°) so lies flat along the shape's bottom edge, not around its
+/// middle.
+fn shadow_local(sh: &deckcraft_model::style::Shadow, w: f64, h: f64) -> Affine {
+    let (ax, ay) = match sh.align.as_str() {
+        "tl" => (0.0, 0.0),
+        "t" => (0.5, 0.0),
+        "tr" => (1.0, 0.0),
+        "l" => (0.0, 0.5),
+        "r" => (1.0, 0.5),
+        "bl" => (0.0, 1.0),
+        "b" => (0.5, 1.0),
+        "br" => (1.0, 1.0),
+        _ => (0.5, 0.5),
+    };
+    let a = Vec2::new(w * ax, h * ay);
+    let (tx, ty) = (sh.kx.to_radians().tan(), sh.ky.to_radians().tan());
+    let k = Affine::new([sh.sx, sh.sy * ty, sh.sx * tx, sh.sy, 0.0, 0.0]);
+    if !k.is_finite() {
+        return Affine::IDENTITY;
+    }
+    Affine::translate(a) * k * Affine::translate(-a)
+}
+
 fn pre_translate(m: Affine, d: Vec2) -> Affine {
     Affine::translate(d) * m
 }
@@ -1036,7 +1406,20 @@ fn blur(sigma: f64) -> Filter {
     Filter::from_primitive(FilterPrimitive::GaussianBlur { std_deviation: sigma.clamp(0.0, 500.0) as f32, edge_mode: EdgeMode::None })
 }
 
-fn stroke(ctx: &mut RenderContext, rctx: &Ctx, line: &Line, ph: Option<Rgba>, path: &BezPath, m: Affine, lw: f64, alpha: f64) {
+/// Stroke `path` with `line`. A gradient line is laid out over `extent` (the untrimmed outline the
+/// line belongs to; `path` itself when `None`).
+#[allow(clippy::too_many_arguments)]
+pub(crate) fn stroke(
+    ctx: &mut RenderContext,
+    rctx: &Ctx,
+    line: &Line,
+    ph: Option<Rgba>,
+    path: &BezPath,
+    extent: Option<&BezPath>,
+    m: Affine,
+    lw: f64,
+    alpha: f64,
+) {
     use deckcraft_model::style::{LineCap, LineJoin};
     let cap = match line.cap.unwrap_or_default() {
         LineCap::Flat => kurbo::Cap::Butt,
@@ -1050,10 +1433,20 @@ fn stroke(ctx: &mut RenderContext, rctx: &Ctx, line: &Line, ph: Option<Rgba>, pa
     };
     // Hairlines stay visible at any zoom.
     let min_w = 0.5 / scale_of(m).max(1e-6);
-    let mut sk = kurbo::Stroke::new(lw.max(min_w)).with_caps(cap).with_join(join);
+    let sw = lw.max(min_w);
+    // PowerPoint's default miter limit is 8 widths (`a:miter lim="800000"`).
+    let mut sk = kurbo::Stroke::new(sw).with_caps(cap).with_join(join).with_miter_limit(8.0);
+    // Square caps on a dashed line square off only the line's own two ends (where a dash is
+    // drawn): each dash itself ends flat, as PowerPoint draws them.
+    let mut square_ends = None;
     if let Some(d) = &line.dash {
         let pat: Vec<f64> = d.pattern().iter().map(|v| v * lw.max(0.75)).collect();
+        let pat = dash_with_caps(pat, cap, sw);
         if !pat.is_empty() && pat.iter().all(|v| *v > 0.0) {
+            if cap == kurbo::Cap::Square {
+                sk = sk.with_caps(kurbo::Cap::Butt);
+                square_ends = Some(square_dash_ends(path, &pat, sw));
+            }
             sk = sk.with_dashes(0.0, pat);
         }
     }
@@ -1062,10 +1455,7 @@ fn stroke(ctx: &mut RenderContext, rctx: &Ctx, line: &Line, ph: Option<Rgba>, pa
         Some(Fill::Solid { color: c }) => {
             ctx.set_paint(color(rctx.color(c, ph), alpha));
         }
-        Some(Fill::Gradient(g)) => {
-            let c = g.stops.first().map(|s| rctx.color(&s.color, ph)).unwrap_or(Rgba::BLACK);
-            ctx.set_paint(color(c, alpha));
-        }
+        Some(Fill::Gradient(g)) if !g.stops.is_empty() => ctx.set_paint(line_gradient(rctx, g, ph, extent.unwrap_or(path), lw, alpha)),
         _ => ctx.set_paint(color(Rgba::BLACK, alpha)),
     }
     // Compound lines: each band stroked along the path moved to its place across the width.
@@ -1083,6 +1473,113 @@ fn stroke(ctx: &mut RenderContext, rctx: &Ctx, line: &Line, ph: Option<Rgba>, pa
     }
     ctx.set_stroke(sk);
     ctx.stroke_path(path);
+    if let Some(ends) = square_ends {
+        ctx.fill_path(&ends);
+    }
+}
+
+/// The square caps of a dashed line drawn `width` wide with dash `pattern`: a half-width square
+/// past the start of each open sub-path (every dash pattern starts with a dash) and past its end
+/// when the pattern is in a dash there.
+fn square_dash_ends(path: &BezPath, pattern: &[f64], width: f64) -> BezPath {
+    use kurbo::{ParamCurve, ParamCurveArclen};
+    let mut out = BezPath::new();
+    let period: f64 = pattern.iter().sum();
+    let mut cap = |at: Point, dir: Vec2| {
+        let n = Vec2::new(-dir.y, dir.x) * (width / 2.0);
+        let back = dir * (width / 2.0);
+        out.move_to(at + n);
+        out.line_to(at + n + back);
+        out.line_to(at - n + back);
+        out.line_to(at - n);
+        out.close_path();
+    };
+    let dir = |seg: &kurbo::PathSeg, t0: f64, t1: f64| {
+        let d = seg.eval(t1) - seg.eval(t0);
+        let d = if d.hypot() > 1e-9 { d } else { seg.end() - seg.start() };
+        if d.hypot() > 1e-9 { Some(d.normalize()) } else { None }
+    };
+    let mut subs: Vec<(Vec<kurbo::PathSeg>, bool)> = vec![];
+    let mut cur: Vec<kurbo::PathSeg> = vec![];
+    let mut closed = false;
+    let mut last = Point::ZERO;
+    let mut start = Point::ZERO;
+    for el in path.elements() {
+        let seg = match *el {
+            PathEl::MoveTo(p) => {
+                if !cur.is_empty() {
+                    subs.push((std::mem::take(&mut cur), closed));
+                }
+                closed = false;
+                last = p;
+                start = p;
+                continue;
+            }
+            PathEl::LineTo(p) => kurbo::PathSeg::Line(kurbo::Line::new(last, p)),
+            PathEl::QuadTo(a, p) => kurbo::PathSeg::Quad(kurbo::QuadBez::new(last, a, p)),
+            PathEl::CurveTo(a, b, p) => kurbo::PathSeg::Cubic(kurbo::CubicBez::new(last, a, b, p)),
+            PathEl::ClosePath => {
+                closed = true;
+                last = start;
+                continue;
+            }
+        };
+        last = seg.end();
+        cur.push(seg);
+    }
+    if !cur.is_empty() {
+        subs.push((cur, closed));
+    }
+    for segs in subs.iter().filter(|(s, c)| !c && !s.is_empty()).map(|(s, _)| s) {
+        let (Some(first), Some(end)) = (segs.first(), segs.last()) else { continue };
+        if let Some(d) = dir(first, 1e-3, 0.0) {
+            cap(first.start(), d);
+        }
+        let len: f64 = segs.iter().map(|s| s.arclen(1e-3)).sum();
+        if !(period > 0.0 && len.is_finite()) {
+            continue;
+        }
+        let mut pos = len % period;
+        // Ending exactly on a period boundary is the end of a gap.
+        let mut on = pos > period * 1e-6;
+        for v in pattern.iter().cycle().take(pattern.len()) {
+            if pos <= *v {
+                break;
+            }
+            pos -= v;
+            on = !on;
+        }
+        if on && let Some(d) = dir(end, 1.0 - 1e-3, 1.0) {
+            cap(end.end(), d);
+        }
+    }
+    out
+}
+
+/// A gradient line's paint: laid out, as PowerPoint lays it, over the box the stroke covers (the
+/// path's bounds grown by half the line width), so a horizontal line's vertical gradient runs
+/// across its width.
+fn line_gradient(rctx: &Ctx, g: &deckcraft_model::style::Gradient, ph: Option<Rgba>, path: &BezPath, lw: f64, alpha: f64) -> peniko::Gradient {
+    let bounds = path.bounding_box().inflate(lw / 2.0, lw / 2.0);
+    let bounds = paint::tile_box(bounds, g.tile);
+    let stops: Vec<(f64, Rgba)> = g.stops.iter().map(|s| (s.pos, rctx.color(&s.color, ph))).collect();
+    paint::gradient(&g.shape, stops, bounds, alpha)
+}
+
+/// A dash pattern (on, off, on, off… lengths) for a line drawn `width` wide with `cap`. As
+/// PowerPoint draws them, round caps sit inside each dash's length rather than adding to it: a
+/// "round dot" (`sysDot`, one width on and one off) is a row of separate circles, not a solid
+/// line. So each dash loses a width (half at each end, where the caps go) and each gap gains it; a
+/// dash no longer than the width becomes just its two caps. (Square-capped dashes end flat; see
+/// `square_dash_ends`.)
+fn dash_with_caps(mut pat: Vec<f64>, cap: kurbo::Cap, width: f64) -> Vec<f64> {
+    if cap != kurbo::Cap::Round || !pat.len().is_multiple_of(2) || !(width.is_finite() && width > 0.0) {
+        return pat;
+    }
+    for (i, v) in pat.iter_mut().enumerate() {
+        *v = if i.is_multiple_of(2) { (*v - width).max(width * 1e-3) } else { *v + width };
+    }
+    pat
 }
 
 fn end_points(path: &BezPath) -> Option<((Point, Point), (Point, Point))> {
@@ -1113,6 +1610,128 @@ fn end_points(path: &BezPath) -> Option<((Point, Point), (Point, Point))> {
     Some(((first, second), (last, prev)))
 }
 
+/// An arrowhead's width and length for a line `lw` wide. PowerPoint sizes them in multiples of
+/// the line width (small 2, medium 3, large 5), but never smaller than for a 2 pt line.
+fn head_size(e: &deckcraft_model::style::LineEnd, lw: f64) -> (f64, f64) {
+    let sz = |s: &str| match s {
+        "sm" => 2.0,
+        "lg" => 5.0,
+        _ => 3.0,
+    };
+    let k = lw.max(2.0);
+    (sz(&e.w) * k, sz(&e.len) * k)
+}
+
+/// How far back from the tip an open arrowhead's legs (`lw` wide) meet along their centre lines:
+/// PowerPoint puts the outside of the point, not the legs' centre lines, on the line's end.
+fn open_arrow_setback(wl: f64, ll: f64, lw: f64) -> f64 {
+    let half = (wl / 2.0).atan2(ll);
+    if half.sin() > 1e-6 { (lw / 2.0 / half.sin()).min(ll) } else { 0.0 }
+}
+
+/// How much of a `lw`-wide line to leave off at its start and end, under its arrowheads: up to
+/// a triangle's base, into a stealth arrow's notch far enough for its barbs to cover the line's
+/// corners, and to where an open arrow's legs meet. Ovals and diamonds sit on the end itself.
+fn head_trims(line: &Line, lw: f64) -> (f64, f64) {
+    // A square cap reaches half a width past the line's end: leave that off too.
+    let cap = if line.cap == Some(deckcraft_model::style::LineCap::Square) { lw / 2.0 } else { 0.0 };
+    let trim = |e: &Option<deckcraft_model::style::LineEnd>| {
+        let Some(e) = e else { return 0.0 };
+        let (wl, ll) = head_size(e, lw);
+        match e.kind.as_str() {
+            "triangle" => ll + cap,
+            "stealth" => (ll * (0.6 + 0.4 * lw / wl.max(1e-9))).min(ll) + cap,
+            "arrow" => open_arrow_setback(wl, ll, lw.max(0.75)) + cap,
+            _ => 0.0,
+        }
+    };
+    (trim(&line.head), trim(&line.tail))
+}
+
+/// `path` with `start` left off the beginning of its first sub-path and `end` off the end of its
+/// last (by arc length), where those are open. A sub-path shorter than its trims disappears.
+fn trim_ends(path: &BezPath, start: f64, end: f64) -> BezPath {
+    use kurbo::{ParamCurve, ParamCurveArclen};
+    const ACC: f64 = 1e-3;
+    let mut subs: Vec<(Vec<kurbo::PathSeg>, bool)> = vec![];
+    let (mut last, mut first) = (Point::ZERO, Point::ZERO);
+    for el in path.elements() {
+        let seg = match *el {
+            PathEl::MoveTo(p) => {
+                subs.push((vec![], false));
+                last = p;
+                first = p;
+                continue;
+            }
+            PathEl::ClosePath => {
+                if let Some(s) = subs.last_mut() {
+                    s.1 = true;
+                }
+                last = first;
+                continue;
+            }
+            PathEl::LineTo(p) => kurbo::PathSeg::Line(kurbo::Line::new(last, p)),
+            PathEl::QuadTo(a, p) => kurbo::PathSeg::Quad(kurbo::QuadBez::new(last, a, p)),
+            PathEl::CurveTo(a, b, p) => kurbo::PathSeg::Cubic(kurbo::CubicBez::new(last, a, b, p)),
+        };
+        last = seg.end();
+        if subs.is_empty() {
+            subs.push((vec![], false));
+        }
+        if let Some(s) = subs.last_mut() {
+            s.0.push(seg);
+        }
+    }
+    if let Some((segs, false)) = subs.first_mut()
+        && start > 0.0
+    {
+        let mut left = start;
+        while let Some(seg) = segs.first().copied() {
+            let l = seg.arclen(ACC);
+            if l > left {
+                if let Some(s0) = segs.first_mut() {
+                    *s0 = seg.subsegment(seg.inv_arclen(left, ACC)..1.0);
+                }
+                break;
+            }
+            left -= l;
+            segs.remove(0);
+        }
+    }
+    if let Some((segs, false)) = subs.last_mut()
+        && end > 0.0
+    {
+        let mut left = end;
+        while let Some(seg) = segs.last().copied() {
+            let l = seg.arclen(ACC);
+            if l > left {
+                if let Some(s1) = segs.last_mut() {
+                    *s1 = seg.subsegment(0.0..seg.inv_arclen(l - left, ACC));
+                }
+                break;
+            }
+            left -= l;
+            segs.pop();
+        }
+    }
+    let mut out = BezPath::new();
+    for (segs, closed) in subs {
+        let Some(s0) = segs.first() else { continue };
+        out.move_to(s0.start());
+        for seg in &segs {
+            match seg {
+                kurbo::PathSeg::Line(l) => out.line_to(l.p1),
+                kurbo::PathSeg::Quad(q) => out.quad_to(q.p1, q.p2),
+                kurbo::PathSeg::Cubic(c) => out.curve_to(c.p1, c.p2, c.p3),
+            }
+        }
+        if closed {
+            out.close_path();
+        }
+    }
+    out
+}
+
 #[allow(clippy::too_many_arguments)]
 fn arrowheads(ctx: &mut RenderContext, rctx: &Ctx, line: &Line, ph: Option<Rgba>, geo: &Geometry, rel: Affine, m: Affine, lw: f64) {
     let Some(sp) = geo.paths.iter().find(|p| p.stroke) else { return };
@@ -1123,18 +1742,25 @@ fn arrowheads(ctx: &mut RenderContext, rctx: &Ctx, line: &Line, ph: Option<Rgba>
         Some(Fill::Solid { color: c }) => rctx.color(c, ph),
         _ => Rgba::BLACK,
     };
-    let lw = lw.max(0.75);
+    // A gradient line's heads take the gradient where they are.
+    let grad = match &line.fill {
+        Some(Fill::Gradient(g)) if !g.stops.is_empty() => {
+            let mut moved = sp.path.clone();
+            moved.apply_affine(rel);
+            Some(line_gradient(rctx, g, ph, &moved, lw, 1.0))
+        }
+        _ => None,
+    };
+    let set_paint = |ctx: &mut RenderContext| match &grad {
+        Some(g) => ctx.set_paint(g.clone()),
+        None => ctx.set_paint(color(col, 1.0)),
+    };
     for (end, tip, from) in [(&line.head, a, a2), (&line.tail, b, b2)] {
         let Some(e) = end else { continue };
         if e.kind == "none" {
             continue;
         }
-        let sz = |s: &str| match s {
-            "sm" => 2.0,
-            "lg" => 5.0,
-            _ => 3.0,
-        };
-        let (wl, ll) = (sz(&e.w) * lw, sz(&e.len) * lw);
+        let (wl, ll) = head_size(e, lw);
         let dir = (tip - from).normalize();
         if !dir.x.is_finite() {
             continue;
@@ -1162,13 +1788,17 @@ fn arrowheads(ctx: &mut RenderContext, rctx: &Ctx, line: &Line, ph: Option<Rgba>
                 p.close_path();
             }
             "arrow" => {
+                // Legs the line's width with round ends, meeting in a sharp point whose outside is
+                // on the line's end.
+                let leg = lw.max(0.75);
+                let back = dir * open_arrow_setback(wl, ll, leg);
                 let mut o = BezPath::new();
-                o.move_to(base + n * wl / 2.0);
-                o.line_to(tip);
-                o.line_to(base - n * wl / 2.0);
+                o.move_to(base + n * wl / 2.0 - back);
+                o.line_to(tip - back);
+                o.line_to(base - n * wl / 2.0 - back);
                 ctx.set_transform(m);
-                ctx.set_paint(color(col, 1.0));
-                ctx.set_stroke(kurbo::Stroke::new(lw).with_join(kurbo::Join::Miter));
+                set_paint(ctx);
+                ctx.set_stroke(kurbo::Stroke::new(leg).with_join(kurbo::Join::Miter).with_miter_limit(100.0).with_caps(kurbo::Cap::Round));
                 ctx.stroke_path(&o);
                 continue;
             }
@@ -1180,7 +1810,7 @@ fn arrowheads(ctx: &mut RenderContext, rctx: &Ctx, line: &Line, ph: Option<Rgba>
             }
         }
         ctx.set_transform(m);
-        ctx.set_paint(color(col, 1.0));
+        set_paint(ctx);
         ctx.fill_path(&p);
     }
 }
@@ -1284,7 +1914,7 @@ pub fn draw_layout_with(ctx: &mut RenderContext, l: &deckcraft_text::TextLayout,
         }
         ctx.set_transform(m * Affine::translate(ps.offset));
         ctx.set_paint(color(d.color, ps.opacity));
-        ctx.fill_rect(&d.rect);
+        fill_deco(ctx, d);
     };
     for d in l.decos.iter().filter(|d| d.behind) {
         deco(ctx, d);
@@ -1311,7 +1941,7 @@ pub fn draw_layout_with(ctx: &mut RenderContext, l: &deckcraft_text::TextLayout,
         // its bottom, from its first to its last character), as in PowerPoint.
         let mut grads: Vec<(usize, peniko::Gradient)> = Vec::new();
         for (gid, x, y) in &run.glyphs {
-            let at = m * Affine::translate((*x, *y));
+            let at = m * glyph_place(run, *gid, *x, *y);
             let Some(g) = run.gradient.as_ref().filter(|g| !g.stops.is_empty()) else {
                 draw_glyph(ctx, run, *gid, at, ps.opacity);
                 continue;
@@ -1332,6 +1962,37 @@ pub fn draw_layout_with(ctx: &mut RenderContext, l: &deckcraft_text::TextLayout,
     }
 }
 
+/// Where glyph `gid` of `run` with its pen at (`x`, `y`) is drawn, in text space: there, turned a
+/// quarter turn back about its em box's centre when it stands upright in vertical text.
+pub(crate) fn glyph_place(run: &deckcraft_text::GlyphRun, gid: u32, x: f64, y: f64) -> Affine {
+    let at = Affine::translate((x, y));
+    match run.upright_centre(gid, x, y) {
+        Some((cx, cy)) => Affine::translate((cx, cy)) * Affine::rotate(-std::f64::consts::FRAC_PI_2) * Affine::translate((-cx, -cy)) * at,
+        None => at,
+    }
+}
+
+/// Fill an underline, strikethrough or highlight with the current paint and transform: its box,
+/// its dashes, or its zigzag stroked.
+pub(crate) fn fill_deco(ctx: &mut RenderContext, d: &deckcraft_text::Deco) {
+    if let Some((pts, w)) = d.wave() {
+        let mut path = BezPath::new();
+        for (i, p) in pts.iter().enumerate() {
+            if i == 0 {
+                path.move_to(*p);
+            } else {
+                path.line_to(*p);
+            }
+        }
+        ctx.set_stroke(kurbo::Stroke::new(w.max(0.01)));
+        ctx.stroke_path(&path);
+        return;
+    }
+    for r in d.pieces() {
+        ctx.fill_rect(&r);
+    }
+}
+
 /// The line of paragraph `para` holding a glyph on baseline `y` (the nearest baseline).
 fn line_at(l: &deckcraft_text::TextLayout, para: usize, y: f64) -> usize {
     l.lines
@@ -1382,7 +2043,7 @@ fn text_effect(ctx: &mut RenderContext, run: &deckcraft_text::GlyphRun, which: T
             continue;
         }
         // The offset is in slide space: a shadow falls the same way whatever the text's rotation.
-        let at = pre_translate(m * Affine::translate((*x, *y)), offset * px) * skew * Affine::scale(k);
+        let at = pre_translate(m * glyph_place(run, *gid, *x, *y), offset * px) * skew * Affine::scale(k);
         ctx.set_transform(at);
         ctx.fill_path(&path);
         if grow > 0.0 {
@@ -1468,6 +2129,9 @@ pub fn render_shape(pres: &Presentation, slide: &Slide, id: ShapeId, scale: f64)
 #[cfg(test)]
 mod tests;
 
+#[cfg(test)]
+mod tests_wild;
+
 #[cfg(test)]
 mod mt_tests {
     use super::*;

crates/render/src/morph_text.rs

@@ -219,7 +219,7 @@ pub(crate) fn draw(
         for d in &l.decos {
             ctx.set_transform(place);
             ctx.set_paint(color(d.color, alpha));
-            ctx.fill_rect(&d.rect);
+            crate::fill_deco(ctx, d);
         }
     }
 }

crates/render/src/paint.rs

@@ -35,6 +35,22 @@ pub fn fill_path(
             if g.stops.is_empty() {
                 return;
             }
+            // `rotWithShape="0"`: the gradient keeps to the slide's axes when the shape is
+            // rotated or flipped, laid out over the box the shape covers on the slide.
+            let c = m.as_coeffs();
+            let turned = c[1].abs() > 1e-9 || c[2].abs() > 1e-9 || c[0] < 0.0 || c[3] < 0.0;
+            let path_kind = matches!(&g.shape, GradientShape::Path { path: k, .. } if matches!(k.as_str(), "rect" | "shape"));
+            if !g.rotate_with_shape && turned && !path_kind && m.determinant().abs() > 1e-12 {
+                let on_slide = m.transform_rect_bbox(bounds);
+                let upright = deckcraft_model::style::Gradient { rotate_with_shape: true, ..g.clone() };
+                let paint_path = m * path.clone();
+                fill_path(ctx, rctx, &Fill::Gradient(upright), ph, &paint_path, on_slide, Affine::IDENTITY, mode, alpha, pres);
+                return;
+            }
+            // A linear gradient spans its tile rectangle (the shape's box unless `tileRect` moves
+            // its edges); a radial one ends on the circle around it, from a focus placed in the
+            // shape's own box (PowerPoint's "from corner" presets centre the tile on the corner).
+            let tile = tile_box(bounds, g.tile);
             let stops: Vec<(f64, Rgba)> = g.stops.iter().map(|s| (s.pos, shade(rctx.color(&s.color, ph), mode))).collect();
             ctx.set_paint(gradient(&g.shape, stops, bounds, alpha));
 
@@ -55,26 +71,30 @@ pub fn fill_path(
                     // Angle measured clockwise from left→right; span the bounds along that direction.
                     let a = angle.to_radians();
                     let (dx, dy) = (a.cos(), a.sin());
-                    let c = bounds.center();
-                    let half = (bounds.width() * dx.abs() + bounds.height() * dy.abs()) / 2.0;
+                    let c = tile.center();
+                    let half = (tile.width() * dx.abs() + tile.height() * dy.abs()) / 2.0;
                     peniko::Gradient::new_linear(Point::new(c.x - dx * half, c.y - dy * half), Point::new(c.x + dx * half, c.y + dy * half))
                         .with_stops(stops.as_slice())
                 }
-                GradientShape::Path { focus, .. } => {
-                    let fx = bounds.x0 + bounds.width() * (focus[0] + (1.0 - focus[2])) / 2.0;
-                    let fy = bounds.y0 + bounds.height() * (focus[1] + (1.0 - focus[3])) / 2.0;
-                    // Reach the farthest corner, so a gradient from a corner covers the whole box.
-                    let r = [(bounds.x0, bounds.y0), (bounds.x1, bounds.y0), (bounds.x0, bounds.y1), (bounds.x1, bounds.y1)]
-                        .iter()
-                        .map(|(x, y)| ((x - fx).powi(2) + (y - fy).powi(2)).sqrt())
-                        .fold(1e-6, f64::max);
-                    peniko::Gradient::new_radial(Point::new(fx, fy), r as f32).with_stops(stops.as_slice())
-                }
+                GradientShape::Path { focus, .. } => circle_gradient(*focus, bounds, tile).with_stops(stops.as_slice()),
             };
             ctx.set_paint(grad);
             ctx.fill_path(path);
         }
         Fill::Picture(pf) => {
+            // `rotWithShape="0"`: upright on the slide, stretched over the box the turned shape
+            // covers, clipped to it.
+            let c = m.as_coeffs();
+            let turned = c[1].abs() > 1e-9 || c[2].abs() > 1e-9 || c[0] < 0.0 || c[3] < 0.0;
+            if pf.upright && turned && m.determinant().abs() > 1e-12 {
+                let on_slide = m.transform_rect_bbox(bounds);
+                let on_path = m * path.clone();
+                ctx.set_transform(Affine::IDENTITY);
+                ctx.push_clip_layer(&on_path);
+                picture(ctx, pres, &resolved(rctx, pf, ph), on_slide, Affine::IDENTITY, None);
+                ctx.pop_layer();
+                return;
+            }
             ctx.push_clip_layer(path);
             picture(ctx, pres, &resolved(rctx, pf, ph), bounds, m, None);
             ctx.pop_layer();
@@ -97,6 +117,22 @@ pub fn resolved<'a>(rctx: &Ctx, pf: &'a PictureFill, ph: Option<Rgba>) -> std::b
     std::borrow::Cow::Owned(out)
 }
 
+/// `bounds` with its edges moved in by `tile` (left, top, right, bottom insets as fractions of its
+/// size; negative moves them out), as `a:tileRect` and `a:fillRect` lay out a fill.
+pub fn tile_box(bounds: Rect, tile: [f64; 4]) -> Rect {
+    if tile.iter().all(|v| *v == 0.0) || tile.iter().any(|v| !v.is_finite()) {
+        return bounds;
+    }
+    let (w, h) = (bounds.width(), bounds.height());
+    let [l, t, r, b] = tile;
+    let x0 = bounds.x0 + l * w;
+    let x1 = bounds.x1 - r * w;
+    let y0 = bounds.y0 + t * h;
+    let y1 = bounds.y1 - b * h;
+    // An inverted tile (insets past each other) lays out nothing sensible: keep the box.
+    if x1 - x0 <= 1e-9 || y1 - y0 <= 1e-9 { bounds } else { Rect::new(x0, y0, x1, y1) }
+}
+
 /// The paint of a gradient of `shape` with `stops` (position, colour) spanning `bounds`, faded
 /// by `alpha`, ramping between stops as PowerPoint does (see `ramp`).
 pub fn gradient(shape: &GradientShape, mut stops: Vec<(f64, Rgba)>, bounds: Rect, alpha: f64) -> peniko::Gradient {
@@ -116,19 +152,34 @@ pub fn gradient(shape: &GradientShape, mut stops: Vec<(f64, Rgba)>, bounds: Rect
             peniko::Gradient::new_linear(Point::new(c.x - dx * half, c.y - dy * half), Point::new(c.x + dx * half, c.y + dy * half))
                 .with_stops(stops.as_slice())
         }
-        GradientShape::Path { focus, .. } => {
-            let fx = bounds.x0 + bounds.width() * (focus[0] + (1.0 - focus[2])) / 2.0;
-            let fy = bounds.y0 + bounds.height() * (focus[1] + (1.0 - focus[3])) / 2.0;
-            // Reach the farthest corner, so a gradient from a corner covers the whole box.
-            let r = [(bounds.x0, bounds.y0), (bounds.x1, bounds.y0), (bounds.x0, bounds.y1), (bounds.x1, bounds.y1)]
-                .iter()
-                .map(|(x, y)| ((x - fx).powi(2) + (y - fy).powi(2)).sqrt())
-                .fold(1e-6, f64::max);
-            peniko::Gradient::new_radial(Point::new(fx, fy), r as f32).with_stops(stops.as_slice())
-        }
+        GradientShape::Path { focus, .. } => circle_gradient(*focus, bounds, bounds).with_stops(stops.as_slice()),
     }
 }
 
+/// A `circle` path gradient over `bounds` with focus rectangle `focus` (`fillToRect` insets, as
+/// fractions). As PowerPoint draws it (fitted to its exports): the first stop is a point at the
+/// focus (the middle of the focus rectangle) and the last is the circle around the whole box (its
+/// centre, half its diagonal), with circles in between moving from one to the other. A focus off
+/// the centre so bunches the colours on its near side; a gradient "from a corner" reaches its
+/// last colour at that corner too, not only at the far one.
+///
+/// With a tile rectangle (`tile`, otherwise `bounds` itself) the end circle is the one around
+/// the tile, while the focus stays placed in `bounds`.
+pub fn circle_gradient(focus: [f64; 4], bounds: Rect, tile: Rect) -> peniko::Gradient {
+    let fx = bounds.x0 + bounds.width() * (focus[0] + (1.0 - focus[2])) / 2.0;
+    let fy = bounds.y0 + bounds.height() * (focus[1] + (1.0 - focus[3])) / 2.0;
+    let c = tile.center();
+    let r = (tile.width().hypot(tile.height()) / 2.0).max(1e-6);
+    let f = Point::new(fx, fy);
+    if !(f.is_finite() && c.is_finite() && r.is_finite()) {
+        return peniko::Gradient::new_radial(c, r as f32);
+    }
+    // A focus on or outside the end circle has no circle through it: keep it just inside.
+    let d = f - c;
+    let f = if d.hypot() > r * 0.999 { c + d * (r * 0.999 / d.hypot()) } else { f };
+    peniko::Gradient::new_two_point_radial(f, 0.0, c, r as f32)
+}
+
 /// Draw a picture fill into `bounds` (shape-local) honouring crop and stretch/tile modes; an animated
 /// GIF shows its frame at `gif_time` seconds.
 pub fn picture(ctx: &mut RenderContext, pres: &Presentation, pf: &PictureFill, bounds: Rect, m: Affine, gif_time: Option<f64>) {
@@ -165,24 +216,67 @@ pub fn picture(ctx: &mut RenderContext, pres: &Presentation, pf: &PictureFill, b
         image: vello_cpu::ImageSource::Pixmap(pm.clone()),
         sampler: peniko::ImageSampler { quality: peniko::ImageQuality::High, ..Default::default() },
     };
-    if let PictureMode::Tile { sx, sy, tx, ty, .. } = &pf.mode {
-        let (sx, sy) = (if *sx > 0.0 { *sx } else { 1.0 }, if *sy > 0.0 { *sy } else { 1.0 });
-        let tile_w = iw * 0.75 * sx;
-        let tile_h = ih * 0.75 * sy;
-        let nx = ((bounds.width() / tile_w.max(1.0)).ceil() as i64).clamp(0, 200);
-        let ny = ((bounds.height() / tile_h.max(1.0)).ceil() as i64).clamp(0, 200);
-        for j in -1..=ny {
-            for i in -1..=nx {
-                let r = Rect::new(bounds.x0 + tx + i as f64 * tile_w, bounds.y0 + ty + j as f64 * tile_h, 0.0, 0.0);
-                let r = Rect::new(r.x0, r.y0, r.x0 + tile_w, r.y0 + tile_h);
-                draw_image(ctx, &image, iw, ih, r, m, alpha);
-            }
+    if let PictureMode::Tile { sx, sy, tx, ty, flip, align } = &pf.mode {
+        // The tile's size: the picture's own size (96 dpi) scaled. A scale of zero or less draws
+        // nothing, as in PowerPoint.
+        if !(*sx > 0.0 && *sy > 0.0 && sx.is_finite() && sy.is_finite()) {
+            return;
+        }
+        let (nw, nh) = images::natural_size(&item.data).unwrap_or((iw, ih));
+        // PowerPoint draws the tile at a whole number of output pixels.
+        let k = px_scale.max(1e-9);
+        let snap = |v: f64| (v * k).round().max(1.0) / k;
+        let (tile_w, tile_h) = (snap(nw * 0.75 * sx), snap(nh * 0.75 * sy));
+        if !(tile_w > 1e-6 && tile_h > 1e-6 && tile_w.is_finite() && tile_h.is_finite()) {
+            return;
+        }
+        let o = tile_origin(bounds, align, (tile_w, tile_h), (*tx, *ty));
+        // Every other tile is mirrored across the flip axes: a reflected repeat.
+        let ext = |mirror: bool| if mirror { peniko::Extend::Reflect } else { peniko::Extend::Repeat };
+        let tiled = vello_cpu::Image {
+            image: vello_cpu::ImageSource::Pixmap(pm.clone()),
+            sampler: peniko::ImageSampler {
+                x_extend: ext(matches!(flip.as_str(), "x" | "xy")),
+                y_extend: ext(matches!(flip.as_str(), "y" | "xy")),
+                quality: peniko::ImageQuality::High,
+                alpha: 1.0,
+            },
+        };
+        ctx.set_transform(m);
+        if alpha < 0.999 {
+            ctx.push_layer(None, None, Some(alpha as f32), None, None);
+        }
+        ctx.set_paint(tiled);
+        ctx.set_paint_transform(Affine::translate(o.to_vec2()) * Affine::scale_non_uniform(tile_w / iw, tile_h / ih));
+        ctx.fill_rect(&bounds);
+        ctx.reset_paint_transform();
+        if alpha < 0.999 {
+            ctx.pop_layer();
         }
         return;
     }
     draw_image(ctx, &image, iw, ih, dest, m, alpha);
 }
 
+/// Where the first tile of a tiled picture fill goes in `bounds`: its corner, edge middle or
+/// centre named by `align` (`tl`, `t`, `tr`, `l`, `ctr`, `r`, `bl`, `b`, `br`) on the same point
+/// of the box, then moved by the offset (points).
+pub fn tile_origin(bounds: Rect, align: &str, tile: (f64, f64), offset: (f64, f64)) -> Point {
+    let (ax, ay) = match align {
+        "t" => (0.5, 0.0),
+        "tr" => (1.0, 0.0),
+        "l" => (0.0, 0.5),
+        "ctr" => (0.5, 0.5),
+        "r" => (1.0, 0.5),
+        "bl" => (0.0, 1.0),
+        "b" => (0.5, 1.0),
+        "br" => (1.0, 1.0),
+        _ => (0.0, 0.0),
+    };
+    let (ox, oy) = (if offset.0.is_finite() { offset.0 } else { 0.0 }, if offset.1.is_finite() { offset.1 } else { 0.0 });
+    Point::new(bounds.x0 + ax * (bounds.width() - tile.0) + ox, bounds.y0 + ay * (bounds.height() - tile.1) + oy)
+}
+
 fn draw_image(ctx: &mut RenderContext, image: &vello_cpu::Image, iw: f64, ih: f64, dest: Rect, m: Affine, alpha: f64) {
     let t = m * Affine::translate(dest.origin().to_vec2()) * Affine::scale_non_uniform(dest.width() / iw, dest.height() / ih);
     ctx.set_transform(t);

crates/render/src/pathgrad.rs

@@ -30,7 +30,32 @@ pub fn position(kind: &str, bounds: Rect, focus: [f64; 4], outline: &[Vec<Point>
     );
     let f = if f.x0 <= f.x1 && f.y0 <= f.y1 { f } else { Rect::from_center_size(f.center(), (0.0, 0.0)) };
     match kind {
-        "shape" if !outline.is_empty() => shape_position(outline, f.center(), p),
+        "shape" if !outline.is_empty() => {
+            // A focus rectangle (not a point) is the first colour throughout, as PowerPoint draws
+            // it; outside, the colour runs from the rectangle's edge to the outline along the ray
+            // from its centre.
+            if f.width() > 1e-9 && f.height() > 1e-9 {
+                if f.contains(p) {
+                    return 0.0;
+                }
+                let c = f.center();
+                let to_outline = shape_position(outline, c, p);
+                let d = (p - c).hypot();
+                if to_outline <= 0.0 || d <= 0.0 {
+                    return 1.0;
+                }
+                // Where the ray leaves the focus rectangle, as a share of the way to `p`.
+                let v = p - c;
+                let kx = if v.x.abs() > 1e-12 { (f.width() / 2.0) / v.x.abs() } else { f64::INFINITY };
+                let ky = if v.y.abs() > 1e-12 { (f.height() / 2.0) / v.y.abs() } else { f64::INFINITY };
+                let rect_share = kx.min(ky).min(1.0);
+                // p is `to_outline` of the way to the outline; the rectangle edge `rect_share` of
+                // the way to p.
+                let outline_share = 1.0 / to_outline; // outline distance in units of |p - c|
+                return ((1.0 - rect_share) / (outline_share - rect_share).max(1e-9)).clamp(0.0, 1.0);
+            }
+            shape_position(outline, f.center(), p)
+        }
         _ => {
             // Distance outside the focus rect along each axis, over the room to that side's edge.
             let axis = |v: f64, lo: f64, hi: f64, edge_lo: f64, edge_hi: f64| {
@@ -55,7 +80,9 @@ fn shape_position(outline: &[Vec<Point>], c: Point, p: Point) -> f64 {
     if len < 1e-9 {
         return 0.0;
     }
-    // Nearest crossing of the ray c + s·d (s > 0) with an edge.
+    // The outline scaled about `c` by t reaches `p` first (smallest t) where the ray's farthest
+    // crossing does: the only crossing for a focus inside a convex outline, and the one that
+    // still works for a focus off the shape (a corner of an ellipse's box).
     let mut best = f64::INFINITY;
     for poly in outline {
         for w in poly.windows(2) {
@@ -69,7 +96,7 @@ fn shape_position(outline: &[Vec<Point>], c: Point, p: Point) -> f64 {
             let s = ac.cross(e) / den;
             let u = ac.cross(d) / den;
             if s > 1e-9 && (-1e-9..=1.0 + 1e-9).contains(&u) {
-                best = best.min(s);
+                best = if best.is_finite() { best.max(s) } else { s };
             }
         }
     }
@@ -207,6 +234,24 @@ mod tests {
         assert!((position("shape", b, CENTRE, &polys, Point::new(140.0, 50.0)) - 0.5).abs() < 1e-6);
     }
 
+    #[test]
+    fn shape_paths_from_off_the_shape_or_a_focus_box() {
+        let b = Rect::new(0.0, 0.0, 280.0, 200.0);
+        let ellipse = polygons(&kurbo::Ellipse::from_rect(b).to_path(0.01));
+        // Focus on the box's corner, outside the ellipse: contours are the ellipse shrunk towards
+        // the corner, so its far edge is the end and its middle part way (it was all the end
+        // colour).
+        let corner = [0.0, 0.0, 1.0, 1.0];
+        let mid = position("shape", b, corner, &ellipse, Point::new(140.0, 100.0));
+        assert!(mid > 0.3 && mid < 0.8, "{mid}");
+        assert!(position("shape", b, corner, &ellipse, Point::new(279.0, 100.0)) > 0.95);
+        // A focus rectangle is the first colour inside, and the colour runs from its edge out.
+        let boxed = [0.25, 0.25, 0.25, 0.25];
+        assert_eq!(position("shape", b, boxed, &ellipse, Point::new(150.0, 110.0)), 0.0);
+        let half = position("shape", b, boxed, &ellipse, Point::new(140.0 + 70.0 + 35.0, 100.0));
+        assert!((half - 0.5).abs() < 0.02, "{half}");
+    }
+
     #[test]
     fn the_ramp_runs_through_the_stops() {
         let stops = [(0.0, Rgba::rgb(0, 0, 0)), (0.5, Rgba::rgb(128, 128, 128)), (1.0, Rgba::rgb(255, 255, 255))];

crates/render/src/pattern.rs

@@ -109,7 +109,10 @@ pub fn fill(ctx: &mut RenderContext, name: &str, fg: Rgba, bg: Rgba, alpha: f64,
         sampler: peniko::ImageSampler {
             x_extend: peniko::Extend::Repeat,
             y_extend: peniko::Extend::Repeat,
-            quality: peniko::ImageQuality::Low,
+            // Bilinear, as PowerPoint samples the tile: exact at a whole number of output pixels
+            // per cell; between, a pixel straddling two cells takes a blend of both (fitted to its
+            // export at 0.75 px per cell: mean error 0.067 against 0.082 for the nearest cell).
+            quality: peniko::ImageQuality::Medium,
             alpha: 1.0,
         },
     });

crates/render/src/table.rs

@@ -348,6 +348,17 @@ pub fn draw(
             },
         }
     }
+    // Diagonal borders, under the edges: drawn like any line (dashes, compound, caps).
+    for (r, c, rect) in &rects {
+        let Some(cell) = t.cell(*r, *c) else { continue };
+        for (line, a, b) in [(&cell.diag_down, (rect.x0, rect.y0), (rect.x1, rect.y1)), (&cell.diag_up, (rect.x0, rect.y1), (rect.x1, rect.y0))] {
+            let Some(l) = line.as_ref().filter(|l| l.fill.as_ref().is_some_and(|f| !f.is_none())) else { continue };
+            let mut p = BezPath::new();
+            p.move_to(a);
+            p.line_to(b);
+            crate::stroke(ctx, rctx, l, None, &p, None, m, l.width.unwrap_or(1.0).max(0.0), 1.0);
+        }
+    }
     // Borders: explicit cell borders, else the style's grid.
     for (r, c, rect) in &rects {
         let Some(cell) = t.cell(*r, *c) else { continue };
@@ -361,11 +372,16 @@ pub fn draw(
         for (i, e) in edges.iter().enumerate() {
             let line = cell.borders.get(i).and_then(|b| b.as_ref());
             let (col, wd) = match line {
-                Some(l) => match &l.fill {
-                    Some(Fill::Solid { color: cc }) => (rctx.color(cc, None), l.width.unwrap_or(1.0)),
-                    Some(Fill::None) => continue,
-                    _ => continue,
-                },
+                // An explicit border is drawn like any line: dashed, compound, gradient.
+                Some(l) => {
+                    if l.fill.as_ref().is_some_and(|f| !f.is_none()) {
+                        let mut p = BezPath::new();
+                        p.move_to((e.0, e.1));
+                        p.line_to((e.2, e.3));
+                        crate::stroke(ctx, rctx, l, None, &p, None, m, l.width.unwrap_or(1.0).max(0.25), 1.0);
+                    }
+                    continue;
+                }
                 None => match lk.sides.get(i).copied().flatten().or(lk.border) {
                     Some(b) if b.0.a > 0 && b.1 > 0.0 => b,
                     _ => continue,

crates/render/src/tests.rs

@@ -125,6 +125,36 @@ fn effects_tables_charts_render() {
     assert!(px[0] < 240 && px[0] == px[2], "{px:?}");
 }
 
+#[test]
+fn combo_chart_draws_columns_and_a_line_on_its_own_axis() {
+    // Columns in the hundreds of thousands, a green line in the thousands on the secondary axis:
+    // the line must sit up in the plot, not flat along the bottom of the primary scale.
+    let mut c = Chart::sample(ChartType::Combo);
+    c.title = None;
+    c.legend = None;
+    c.series.truncate(2);
+    c.categories = vec!["A".into(), "B".into(), "C".into()];
+    c.series[0].kind = Some(ChartType::Column);
+    c.series[0].values = vec![Some(200_000.0), Some(300_000.0), Some(250_000.0)];
+    c.series[1].kind = Some(ChartType::Line);
+    c.series[1].values = vec![Some(7_000.0), Some(7_000.0), Some(7_000.0)];
+    c.series[1].secondary_axis = true;
+    c.series[1].line = Some(deckcraft_model::style::Line::solid(ColorRef::rgb(deckcraft_color::Rgba::rgb(0, 176, 80)), 3.0));
+    let sh = Shape { id: ShapeId(620), xfrm: Some(Xfrm::new(0.0, 0.0, 960.0, 540.0)), kind: ShapeKind::Chart(Box::new(c)), ..Default::default() };
+    let img = render_slide(&deck_with(vec![sh]), 0, &RenderOpts { scale: 1.0, ..Default::default() });
+    let green = |x: u32, y0: u32, y1: u32| {
+        (y0..y1).any(|y| {
+            let p = img.pixel(x, y);
+            p[1] > 120 && p[0] < 80 && p[2] < 140
+        })
+    };
+    // The line is in the upper half (7 000 of an axis to 8 000), and columns fill the plot's bottom.
+    assert!(green(480, 20, 270), "line not in the upper half");
+    assert!(!green(480, 400, 500), "line along the bottom");
+    let col = img.pixel(480, 480);
+    assert!(col[0] < 250 || col[1] < 250 || col[2] < 250, "no column: {col:?}");
+}
+
 #[test]
 fn placeholder_prompts_only_in_edit_view() {
     let p = Presentation::default();
@@ -535,6 +565,7 @@ fn a_linear_gradient_ramps_like_powerpoint() {
         id: ShapeId(700),
         xfrm: Some(Xfrm::new(0.0, 0.0, 800.0, 100.0)),
         fill: Some(Fill::Gradient(Gradient {
+            tile: [0.0; 4],
             stops: vec![stop(0.0, deckcraft_color::Rgba::rgb(0, 0, 0)), stop(1.0, deckcraft_color::Rgba::rgb(255, 255, 255))],
             shape: GradientShape::Linear { angle: 0.0, scaled: false },
             rotate_with_shape: true,
@@ -559,6 +590,7 @@ fn a_gradient_with_a_stop_off_the_end_stays_linear() {
         id: ShapeId(701),
         xfrm: Some(Xfrm::new(0.0, 0.0, 800.0, 100.0)),
         fill: Some(Fill::Gradient(Gradient {
+            tile: [0.0; 4],
             stops: vec![stop(0.2, deckcraft_color::Rgba::rgb(0, 0, 0)), stop(1.0, deckcraft_color::Rgba::rgb(255, 255, 255))],
             shape: GradientShape::Linear { angle: 0.0, scaled: false },
             rotate_with_shape: true,
@@ -599,6 +631,7 @@ fn a_shape_filled_with_the_background_shows_the_slide_background() {
     let stop = |pos, v| GradientStop { pos, color: ColorRef::rgb(deckcraft_color::Rgba::rgb(v, v, v)) };
     std::sync::Arc::make_mut(&mut p.slides[0]).background = Some(deckcraft_model::Background::Fill {
         fill: Fill::Gradient(Gradient {
+            tile: [0.0; 4],
             stops: vec![stop(0.0, 0), stop(0.5, 0), stop(1.0, 200)],
             shape: GradientShape::Linear { angle: 0.0, scaled: false },
             rotate_with_shape: true,
@@ -672,6 +705,7 @@ fn a_text_gradient_starts_over_on_every_line() {
         let props = &mut p.runs[0].props;
         props.size = Some(80.0);
         props.fill = Some(Fill::Gradient(Gradient {
+            tile: [0.0; 4],
             stops: vec![stop(0.0, 0), stop(1.0, 255)],
             shape: GradientShape::Linear { angle: 90.0, scaled: false },
             rotate_with_shape: true,
@@ -832,6 +866,7 @@ fn rect_path_gradients_draw_x_shaped_contours() {
         id: ShapeId(770),
         xfrm: Some(Xfrm::new(0.0, 0.0, 280.0, 200.0)),
         fill: Some(Fill::Gradient(Gradient {
+            tile: [0.0; 4],
             stops: vec![stop(0.0, 0), stop(0.5, 128), stop(1.0, 255)],
             shape: GradientShape::Path { path: "rect".into(), focus: [0.5, 0.5, 0.5, 0.5] },
             rotate_with_shape: true,
@@ -1506,3 +1541,173 @@ fn group_child_scale_does_not_scale_line_widths() {
         assert!(d * 20 < drawn, "{name}: {d} differing values against {drawn} inked pixels");
     }
 }
+
+#[test]
+fn a_picture_casts_its_shadow_from_its_pixels() {
+    // PowerPoint shades only where a picture paints: a logo on a transparent background casts the
+    // logo's shadow, not its frame's. Here the left half of the image is transparent.
+    let png = {
+        let img = image::RgbaImage::from_fn(8, 4, |x, _| if x < 4 { image::Rgba([0, 0, 0, 0]) } else { image::Rgba([20, 160, 20, 255]) });
+        let mut out = std::io::Cursor::new(vec![]);
+        image::DynamicImage::ImageRgba8(img).write_to(&mut out, image::ImageFormat::Png).unwrap();
+        out.into_inner()
+    };
+    let shadow = deckcraft_model::style::Shadow {
+        color: ColorRef::rgb(deckcraft_color::Rgba::BLACK),
+        blur: 0.0,
+        dist: 20.0,
+        dir: 90.0,
+        inner: false,
+        sx: 1.0,
+        sy: 1.0,
+        kx: 0.0,
+        ky: 0.0,
+        align: String::new(),
+        rotate_with_shape: false,
+    };
+    for as_fill in [false, true] {
+        let mut p = Presentation::default();
+        let media = p.add_media("logo.png", "image/png", png.clone());
+        let pf = deckcraft_model::style::PictureFill { media, ..Default::default() };
+        let mut sh = Shape { id: ShapeId(600), xfrm: Some(Xfrm::new(100.0, 100.0, 400.0, 200.0)), ..Default::default() };
+        if as_fill {
+            sh.fill = Some(Fill::Picture(pf));
+            sh.line = Some(deckcraft_model::style::Line { fill: Some(Fill::None), ..Default::default() });
+        } else {
+            sh.kind = ShapeKind::Picture { fill: pf };
+        }
+        sh.effects = Some(deckcraft_model::Effects { outer_shadow: Some(shadow.clone()), ..Default::default() });
+        std::sync::Arc::make_mut(&mut p.slides[0]).shapes = vec![sh];
+        let img = render_slide(&p, 0, &RenderOpts { scale: 1.0, ..Default::default() });
+        // Below the picture, 10 pt down: shadow under the opaque right half only.
+        let left = img.pixel(200, 310);
+        let right = img.pixel(400, 310);
+        assert!(left[0] > 240, "no shadow under the transparent half ({as_fill}): {left:?}");
+        assert!(right[0] < 40, "shadow under the opaque half ({as_fill}): {right:?}");
+        // The transparent half shows the slide, not a shadow behind it.
+        assert!(img.pixel(200, 200)[0] > 240, "{as_fill}");
+    }
+}
+
+#[test]
+fn text_in_a_scaled_group_keeps_its_point_size() {
+    // A group's child coordinates scale its shapes' boxes, never their type: a 24 pt word in a
+    // group whose child space is 1/1600 of its size (as old decks write them) or 4 times it is
+    // 24 pt on the slide, and inside its box (it used to grow until the slide turned black).
+    let draw = |scale: f64| {
+        let mut p = Presentation::default();
+        let mut body = TextBody::from_text("Hello");
+        body.paragraphs[0].runs[0].props.size = Some(24.0);
+        body.paragraphs[0].runs[0].props.fill = Some(Fill::solid(ColorRef::rgb(deckcraft_color::Rgba::BLACK)));
+        let child = Shape { id: ShapeId(601), xfrm: Some(Xfrm::new(0.0, 0.0, 400.0 / scale, 200.0 / scale)), text: Some(body), ..Default::default() };
+        let g = Shape {
+            id: ShapeId(600),
+            xfrm: Some(Xfrm::new(100.0, 100.0, 400.0, 200.0)),
+            kind: ShapeKind::Group { children: vec![child], child: Xfrm::new(0.0, 0.0, 400.0 / scale, 200.0 / scale) },
+            ..Default::default()
+        };
+        std::sync::Arc::make_mut(&mut p.slides[0]).shapes = vec![g];
+        render_slide(&p, 0, &RenderOpts { scale: 1.0, ..Default::default() })
+    };
+    let ((_, y0, _, y1), _) = ink(&draw(1.0));
+    let plain = y1 - y0;
+    assert!(plain > 10 && plain < 30, "24 pt word ink height {plain}");
+    for scale in [1600.0, 4.0, 0.25] {
+        let ((x0, sy0, x1, sy1), _) = ink(&draw(scale));
+        assert!((sy1 - sy0).abs_diff(plain) <= 1, "scale {scale}: ink height {} vs {plain}", sy1 - sy0);
+        assert!(x0 >= 100 && x1 <= 500 && sy0 >= 100 && sy1 <= 300, "scale {scale}: ink inside the box");
+    }
+}
+
+#[test]
+fn a_fill_overlay_blends_over_the_fill() {
+    // `a:fillOverlay blend="mult"`: a 50% grey multiplied over a light fill darkens it; "screen"
+    // lightens a dark one; the overlay stays inside the shape.
+    use deckcraft_model::style::FillOverlay;
+    let draw = |base: [u8; 3], blend: &str| {
+        let mut p = Presentation::default();
+        let mut sh = Shape {
+            id: ShapeId(600),
+            xfrm: Some(Xfrm::new(100.0, 100.0, 200.0, 100.0)),
+            fill: Some(Fill::solid(ColorRef::rgb(deckcraft_color::Rgba::rgb(base[0], base[1], base[2])))),
+            line: Some(deckcraft_model::style::Line { fill: Some(Fill::None), ..Default::default() }),
+            ..Default::default()
+        };
+        sh.effects = Some(deckcraft_model::Effects {
+            fill_overlay: Some(FillOverlay { blend: blend.into(), fill: Fill::solid(ColorRef::rgb(deckcraft_color::Rgba::rgb(128, 128, 128))) }),
+            ..Default::default()
+        });
+        std::sync::Arc::make_mut(&mut p.slides[0]).shapes = vec![sh];
+        let img = render_slide(&p, 0, &RenderOpts { scale: 1.0, ..Default::default() });
+        (img.pixel(200, 150), img.pixel(50, 50))
+    };
+    let (mult, outside) = draw([200, 100, 50], "mult");
+    assert!((mult[0] as i32 - 100).abs() <= 3 && (mult[1] as i32 - 50).abs() <= 3 && (mult[2] as i32 - 25).abs() <= 3, "{mult:?}");
+    assert_eq!(&outside[..3], &[255, 255, 255], "nothing outside the shape");
+    let (screen, _) = draw([0, 0, 0], "screen");
+    assert!((screen[0] as i32 - 128).abs() <= 3, "{screen:?}");
+    let (over, _) = draw([200, 100, 50], "over");
+    assert!((over[0] as i32 - 128).abs() <= 3 && (over[1] as i32 - 128).abs() <= 3, "{over:?}");
+}
+
+#[test]
+fn dotted_and_wavy_underlines_draw_their_pattern() {
+    // Underlined spaces only, so the underline is the only ink: a red line under "      ".
+    let row_runs = |u: &str| {
+        let mut sh = Shape { id: ShapeId(760), xfrm: Some(Xfrm::new(0.0, 0.0, 900.0, 300.0)), text_box: true, ..Default::default() };
+        let mut t = TextBody::from_text("            ");
+        let props = &mut t.paragraphs[0].runs[0].props;
+        props.size = Some(96.0);
+        props.underline = Some(u.into());
+        props.fill = Some(deckcraft_model::style::Fill::solid(ColorRef::rgb(deckcraft_color::Rgba::rgb(255, 0, 0))));
+        sh.text = Some(t);
+        let p = deck_with(vec![sh]);
+        let img = render_slide(&p, 0, &RenderOpts { scale: 1.0, ..Default::default() });
+        let red = |x: u32, y: u32| {
+            let px = img.pixel(x, y);
+            px[0] > 150 && px[1] < 120
+        };
+        // The ink's rows, and the number of separate red stretches along the most inked row.
+        let rows: Vec<u32> = (0..300).filter(|&y| (0..900).any(|x| red(x, y))).collect();
+        let best = rows.iter().copied().max_by_key(|&y| (0..900).filter(|&x| red(x, y)).count()).unwrap_or(0);
+        let stretches = (1..900).filter(|&x| red(x, best) && !red(x - 1, best)).count();
+        (rows.len(), stretches)
+    };
+    let (sng_rows, sng_runs) = row_runs("sng");
+    assert_eq!(sng_runs, 1, "a single line is one stretch");
+    let (_, dotted_runs) = row_runs("dotted");
+    assert!(dotted_runs > 10, "dots: {dotted_runs}");
+    let (wavy_rows, _) = row_runs("wavy");
+    assert!(wavy_rows > sng_rows, "a wave spans more rows ({wavy_rows}) than a single line ({sng_rows})");
+}
+
+#[test]
+fn east_asian_vertical_text_stands_ideographs_upright() {
+    // "一" is a horizontal stroke. In eaVert text it stays horizontal (upright) while the line runs
+    // down the shape; in vert it lies on its side like Latin text.
+    let ink = |dir: deckcraft_model::text::TextDir| {
+        let mut sh = Shape { id: ShapeId(770), xfrm: Some(Xfrm::new(100.0, 50.0, 200.0, 400.0)), text_box: true, ..Default::default() };
+        let mut t = TextBody::from_text("一");
+        t.body.vert = Some(dir);
+        let props = &mut t.paragraphs[0].runs[0].props;
+        props.size = Some(80.0);
+        props.fill = Some(deckcraft_model::style::Fill::solid(ColorRef::rgb(deckcraft_color::Rgba::rgb(0, 0, 0))));
+        sh.text = Some(t);
+        let p = deck_with(vec![sh]);
+        let img = render_slide(&p, 0, &RenderOpts { scale: 1.0, ..Default::default() });
+        let (mut x0, mut y0, mut x1, mut y1) = (u32::MAX, u32::MAX, 0, 0);
+        for y in 0..540 {
+            for x in 0..960 {
+                if img.pixel(x, y)[0] < 128 {
+                    (x0, y0, x1, y1) = (x0.min(x), y0.min(y), x1.max(x), y1.max(y));
+                }
+            }
+        }
+        assert!(x1 >= x0 && y1 >= y0, "no ink for {dir:?}");
+        (x1 - x0, y1 - y0)
+    };
+    let (w, h) = ink(deckcraft_model::text::TextDir::EaVertical);
+    assert!(w > h * 3, "eaVert: upright stroke {w}x{h}");
+    let (w, h) = ink(deckcraft_model::text::TextDir::Vertical);
+    assert!(h > w * 3, "vert: stroke on its side {w}x{h}");
+}

crates/render/src/tests_wild.rs

@@ -0,0 +1,746 @@
+//! Render tests for shape, line, fill and effect cases checked against PowerPoint's own exports
+//! of synthetic "wild" slides (observed black-box; see `plan/powerpoint/tools/gen_wild.py`).
+
+use super::*;
+use deckcraft_color::Rgba;
+use deckcraft_model::style::ColorRef;
+use deckcraft_model::{CustomPath, Geom, Presentation, Shape, ShapeId, Xfrm};
+
+fn deck_with(shapes: Vec<Shape>) -> Presentation {
+    let mut p = Presentation::default();
+    let s = std::sync::Arc::make_mut(&mut p.slides[0]);
+    s.shapes = shapes;
+    p
+}
+
+fn render(shapes: Vec<Shape>) -> Image {
+    render_slide(&deck_with(shapes), 0, &RenderOpts { scale: 1.0, ..Default::default() })
+}
+
+fn solid(c: Rgba) -> Option<Fill> {
+    Some(Fill::solid(ColorRef::rgb(c)))
+}
+
+fn no_line() -> Option<Line> {
+    Some(Line { fill: Some(Fill::None), ..Default::default() })
+}
+
+fn close(px: [u8; 4], c: Rgba, tol: i32) -> bool {
+    (px[0] as i32 - c.r as i32).abs() <= tol && (px[1] as i32 - c.g as i32).abs() <= tol && (px[2] as i32 - c.b as i32).abs() <= tol
+}
+
+const WHITE: Rgba = Rgba::WHITE;
+const RED: Rgba = Rgba::rgb(255, 0, 0);
+
+#[test]
+fn custom_geometry_sub_paths_cut_holes_whichever_way_they_wind() {
+    // Outer square clockwise, inner square also clockwise: PowerPoint still shows a hole.
+    let d = "M 0 0 L 100 0 L 100 100 L 0 100 Z M 25 25 L 75 25 L 75 75 L 25 75 Z";
+    let sh = Shape {
+        id: ShapeId(10),
+        xfrm: Some(Xfrm::new(100.0, 100.0, 200.0, 200.0)),
+        geom: Geom::Custom { paths: vec![CustomPath { w: 100.0, h: 100.0, d: d.into(), ..Default::default() }] },
+        fill: solid(RED),
+        line: no_line(),
+        ..Default::default()
+    };
+    let img = render(vec![sh]);
+    assert!(close(img.pixel(120, 120), RED, 2), "outer ring filled");
+    assert!(close(img.pixel(200, 200), WHITE, 2), "inner square is a hole: {:?}", img.pixel(200, 200));
+}
+
+fn dotted_line(cap: deckcraft_model::style::LineCap, len: f64) -> Shape {
+    Shape {
+        id: ShapeId(11),
+        xfrm: Some(Xfrm::new(100.0, 100.0, len, 0.0)),
+        geom: Geom::preset("line"),
+        line: Some(Line {
+            fill: solid(RED),
+            width: Some(10.0),
+            dash: Some(deckcraft_model::style::Dash::Preset { name: "sysDot".into() }),
+            cap: Some(cap),
+            ..Default::default()
+        }),
+        ..Default::default()
+    }
+}
+
+#[test]
+fn round_dots_are_separate_circles_with_the_caps_inside_each_dash() {
+    use deckcraft_model::style::LineCap;
+    // PowerPoint's "Round Dot": one width on, one off, round caps. The caps sit inside the dash, so
+    // the dots stay apart (they used to grow into each other and draw a solid line).
+    let img = render(vec![dotted_line(LineCap::Round, 200.0)]);
+    assert!(close(img.pixel(100, 100), RED, 40), "a dot centred on the start {:?}", img.pixel(100, 100));
+    assert!(close(img.pixel(120, 100), RED, 40), "the next dot one period on");
+    assert!(close(img.pixel(110, 100), WHITE, 10), "a gap between dots {:?}", img.pixel(110, 100));
+    // Flat caps: each dash is a width long, from the start.
+    let img = render(vec![dotted_line(LineCap::Flat, 200.0)]);
+    assert!(close(img.pixel(105, 100), RED, 40) && close(img.pixel(115, 100), WHITE, 10));
+    // Square caps: dashes end flat; only the line's own start is squared off, half a width back.
+    let img = render(vec![dotted_line(LineCap::Square, 200.0)]);
+    assert!(close(img.pixel(97, 100), RED, 40), "square cap before the start {:?}", img.pixel(97, 100));
+    assert!(close(img.pixel(105, 100), RED, 40) && close(img.pixel(115, 100), WHITE, 10), "dashes keep their length");
+    assert!(close(img.pixel(122, 100), RED, 40) && close(img.pixel(118, 100), WHITE, 10), "no cap on the next dash");
+    // The end: 200 pt is ten whole periods, so the line ends in a gap and gets no cap.
+    assert!(close(img.pixel(302, 100), WHITE, 10), "{:?}", img.pixel(302, 100));
+    // 205 pt ends half way through a dash: squared off past the end.
+    let img = render(vec![dotted_line(LineCap::Square, 205.0)]);
+    assert!(close(img.pixel(308, 100), RED, 40), "{:?}", img.pixel(308, 100));
+}
+
+#[test]
+fn dash_lengths_make_room_for_round_and_square_caps() {
+    assert_eq!(dash_with_caps(vec![4.0, 3.0], kurbo::Cap::Round, 1.0), vec![3.0, 4.0]);
+    assert_eq!(dash_with_caps(vec![1.0, 1.0], kurbo::Cap::Round, 2.0), vec![0.002, 3.0]);
+    assert_eq!(dash_with_caps(vec![1.0, 1.0], kurbo::Cap::Square, 2.0), vec![1.0, 1.0]);
+    assert_eq!(dash_with_caps(vec![4.0, 3.0], kurbo::Cap::Butt, 1.0), vec![4.0, 3.0]);
+    assert_eq!(dash_with_caps(vec![4.0, 3.0, 1.0], kurbo::Cap::Round, 1.0), vec![4.0, 3.0, 1.0]);
+}
+
+fn arrow_line(kind: &str, width: f64, c: Rgba) -> Shape {
+    let end = deckcraft_model::style::LineEnd { kind: kind.into(), w: "med".into(), len: "med".into() };
+    Shape {
+        id: ShapeId(12),
+        xfrm: Some(Xfrm::new(100.0, 100.0, 200.0, 0.0)),
+        geom: Geom::preset("line"),
+        line: Some(Line { fill: solid(c), width: Some(width), tail: Some(end), ..Default::default() }),
+        ..Default::default()
+    }
+}
+
+#[test]
+fn a_wide_line_stops_inside_its_arrowhead() {
+    // 10 pt line, medium triangle (30 pt long, 30 wide) whose tip is the line's end at x = 300.
+    let img = render(vec![arrow_line("triangle", 10.0, RED)]);
+    assert!(close(img.pixel(297, 100), RED, 40), "the tip {:?}", img.pixel(297, 100));
+    // 2 pt back from the tip the triangle is 2 pt wide: the line's corner must not show there.
+    assert!(close(img.pixel(298, 104), WHITE, 10), "line corner past the head {:?}", img.pixel(298, 104));
+}
+
+#[test]
+fn a_see_through_line_and_its_arrowhead_are_one_shape() {
+    let half_red = Rgba::rgba(255, 0, 0, 128);
+    let img = render(vec![arrow_line("triangle", 10.0, half_red)]);
+    let line_only = img.pixel(200, 100);
+    let head_over_line = img.pixel(285, 100);
+    assert!(close(line_only, Rgba::rgb(255, 127, 127), 6), "{line_only:?}");
+    assert!(close(head_over_line, Rgba::rgb(line_only[0], line_only[1], line_only[2]), 3), "no darker overlap: {head_over_line:?}");
+}
+
+#[test]
+fn an_open_arrowheads_point_is_on_the_lines_end() {
+    let img = render(vec![arrow_line("arrow", 8.0, RED)]);
+    let reach = (290..320).rev().find(|x| img.pixel(*x, 100)[1] < 128);
+    assert!(reach.is_some_and(|x| x <= 300), "point reaches {reach:?}");
+    assert!(reach.is_some_and(|x| x >= 297), "point reaches {reach:?}");
+}
+
+#[test]
+fn arrowheads_are_sized_for_at_least_a_two_point_line() {
+    let e = deckcraft_model::style::LineEnd { kind: "triangle".into(), w: "sm".into(), len: "lg".into() };
+    assert_eq!(head_size(&e, 0.5), (4.0, 10.0));
+    assert_eq!(head_size(&e, 4.0), (8.0, 20.0));
+}
+
+#[test]
+fn trimming_a_path_leaves_its_ends_off_by_arc_length() {
+    let mut p = BezPath::new();
+    p.move_to((0.0, 0.0));
+    p.line_to((50.0, 0.0));
+    p.line_to((50.0, 50.0));
+    let t = trim_ends(&p, 10.0, 20.0);
+    let els = t.elements();
+    assert_eq!(els.first(), Some(&PathEl::MoveTo(Point::new(10.0, 0.0))));
+    match els.last() {
+        Some(PathEl::LineTo(q)) => assert!((q.x - 50.0).abs() < 1e-6 && (q.y - 30.0).abs() < 1e-6, "{q:?}"),
+        other => panic!("{other:?}"),
+    }
+    // Trims longer than the path leave nothing; closed paths are untouched.
+    assert!(trim_ends(&p, 60.0, 50.0).elements().is_empty());
+    let r = Rect::new(0.0, 0.0, 10.0, 10.0).to_path(0.1);
+    assert_eq!(trim_ends(&r, 3.0, 3.0).elements().len(), r.elements().len());
+}
+
+fn radial(focus: [f64; 4]) -> Shape {
+    use deckcraft_model::style::{Gradient, GradientShape, GradientStop};
+    let stops = vec![GradientStop { pos: 0.0, color: ColorRef::rgb(WHITE) }, GradientStop { pos: 1.0, color: ColorRef::rgb(Rgba::BLACK) }];
+    Shape {
+        id: ShapeId(13),
+        xfrm: Some(Xfrm::new(100.0, 100.0, 400.0, 200.0)),
+        fill: Some(Fill::Gradient(Gradient {
+            tile: [0.0; 4],
+            stops,
+            shape: GradientShape::Path { path: "circle".into(), focus },
+            rotate_with_shape: true,
+        })),
+        line: no_line(),
+        ..Default::default()
+    }
+}
+
+#[test]
+fn a_radial_gradient_off_centre_ends_on_the_circle_around_the_box() {
+    // Focus a fifth of the way in from the top-left corner. PowerPoint's last colour is reached on
+    // the circle through the box's corners, so the near corner is dark as well as the far one.
+    let img = render(vec![radial([0.2, 0.2, 0.8, 0.8])]);
+    assert!(img.pixel(181, 141)[0] > 240, "white at the focus {:?}", img.pixel(181, 141));
+    assert!(img.pixel(101, 101)[0] < 60, "near corner dark {:?}", img.pixel(101, 101));
+    assert!(img.pixel(498, 298)[0] < 60, "far corner dark {:?}", img.pixel(498, 298));
+    // Straight above the focus the box's edge is well inside the circle: still light.
+    assert!(img.pixel(181, 101)[0] > 150, "{:?}", img.pixel(181, 101));
+    // A centred one is symmetric, dark only at the corners.
+    let img = render(vec![radial([0.5, 0.5, 0.5, 0.5])]);
+    assert!(img.pixel(300, 200)[0] > 240 && img.pixel(101, 101)[0] < 60);
+    assert!((img.pixel(110, 200)[0] as i32 - img.pixel(490, 200)[0] as i32).abs() <= 2);
+}
+
+fn shadow(sx: f64, sy: f64, kx: f64, align: &str) -> deckcraft_model::style::Shadow {
+    deckcraft_model::style::Shadow {
+        color: ColorRef::rgb(Rgba::BLACK),
+        blur: 0.0,
+        dist: 0.0,
+        dir: 0.0,
+        inner: false,
+        sx,
+        sy,
+        kx,
+        ky: 0.0,
+        align: align.into(),
+        rotate_with_shape: false,
+    }
+}
+
+fn with_effects(fill: Option<Fill>, line: Option<Line>, effects: deckcraft_model::Effects) -> Shape {
+    Shape { id: ShapeId(14), xfrm: Some(Xfrm::new(100.0, 100.0, 100.0, 100.0)), fill, line, effects: Some(effects), ..Default::default() }
+}
+
+#[test]
+fn a_perspective_shadow_lies_along_the_edge_its_alignment_names() {
+    // Half height, skewed 45° so its top leans right, anchored at the bottom middle: the shadow's
+    // bottom edge is the shape's (y = 200) and its top (y = 150) is 50 pt to the right.
+    let fx = deckcraft_model::Effects { outer_shadow: Some(shadow(1.0, 0.5, -45.0, "b")), ..Default::default() };
+    let img = render(vec![with_effects(solid(RED), no_line(), fx)]);
+    assert!(close(img.pixel(210, 175), Rgba::BLACK, 30), "{:?}", img.pixel(210, 175));
+    assert!(close(img.pixel(240, 155), Rgba::BLACK, 30), "{:?}", img.pixel(240, 155));
+    assert!(close(img.pixel(240, 180), WHITE, 10), "{:?}", img.pixel(240, 180));
+    assert!(close(img.pixel(205, 140), WHITE, 10), "nothing above the half height {:?}", img.pixel(205, 140));
+    // Anchored bottom-right and half as big again: it grows up and to the left only.
+    let fx = deckcraft_model::Effects { outer_shadow: Some(shadow(1.5, 1.5, 0.0, "br")), ..Default::default() };
+    let img = render(vec![with_effects(solid(RED), no_line(), fx)]);
+    assert!(close(img.pixel(70, 70), Rgba::BLACK, 30) && close(img.pixel(210, 210), WHITE, 10));
+}
+
+fn offset_shadow() -> deckcraft_model::Effects {
+    let mut sh = shadow(1.0, 1.0, 0.0, "b");
+    sh.dist = 20.0;
+    sh.dir = 0.0;
+    deckcraft_model::Effects { outer_shadow: Some(sh), ..Default::default() }
+}
+
+#[test]
+fn shadows_are_cast_by_what_is_drawn() {
+    // An outline-only square: its shadow (20 pt to the right) is a frame, not a solid square.
+    let outline = Some(Line::solid(ColorRef::rgb(RED), 4.0));
+    let img = render(vec![with_effects(Some(Fill::None), outline.clone(), offset_shadow())]);
+    assert!(close(img.pixel(220, 150), Rgba::BLACK, 30), "the frame's shadow {:?}", img.pixel(220, 150));
+    assert!(close(img.pixel(160, 150), WHITE, 10), "no shadow inside the frame {:?}", img.pixel(160, 150));
+    // A half see-through fill casts a half see-through shadow.
+    let img = render(vec![with_effects(solid(Rgba::rgba(255, 0, 0, 128)), no_line(), offset_shadow())]);
+    let px = img.pixel(210, 150);
+    assert!(close(px, Rgba::rgb(127, 127, 127), 8), "half shadow {px:?}");
+    // A line casts a shadow too.
+    let mut ln = arrow_line("none", 6.0, RED);
+    ln.effects = Some(offset_shadow());
+    let img = render(vec![ln]);
+    assert!(close(img.pixel(310, 100), Rgba::BLACK, 30), "line shadow {:?}", img.pixel(310, 100));
+}
+
+#[allow(clippy::unwrap_used)]
+fn png(w: u32, h: u32, rgb: [u8; 3]) -> Vec<u8> {
+    let mut out = std::io::Cursor::new(vec![]);
+    image::DynamicImage::ImageRgb8(image::RgbImage::from_pixel(w, h, image::Rgb(rgb))).write_to(&mut out, image::ImageFormat::Png).unwrap();
+    out.into_inner()
+}
+
+fn picture_deck(line: Option<Line>) -> Presentation {
+    let mut p = Presentation::default();
+    let media = p.add_media("image1.png", "image/png", png(8, 8, [0, 0, 255]));
+    let sh = Shape {
+        id: ShapeId(15),
+        xfrm: Some(Xfrm::new(100.0, 100.0, 200.0, 100.0)),
+        kind: ShapeKind::Picture { fill: deckcraft_model::style::PictureFill { media, ..Default::default() } },
+        line,
+        ..Default::default()
+    };
+    std::sync::Arc::make_mut(&mut p.slides[0]).shapes = vec![sh];
+    p
+}
+
+#[test]
+fn a_pictures_border_lies_outside_the_picture() {
+    let p = picture_deck(Some(Line::solid(ColorRef::rgb(RED), 8.0)));
+    let img = render_slide(&p, 0, &RenderOpts { scale: 1.0, ..Default::default() });
+    let blue = Rgba::rgb(0, 0, 255);
+    // The whole picture shows, up to its edge; the 8 pt border is all outside it.
+    assert!(close(img.pixel(101, 150), blue, 30), "picture at its edge {:?}", img.pixel(101, 150));
+    assert!(close(img.pixel(98, 150), RED, 30) && close(img.pixel(93, 150), RED, 30), "{:?}", img.pixel(93, 150));
+    assert!(close(img.pixel(90, 150), WHITE, 10), "border no wider than the line {:?}", img.pixel(90, 150));
+    // A dashed border keeps its dash lengths (a dash is 4 widths: 32 pt), drawn from the corner.
+    let mut line = Line::solid(ColorRef::rgb(RED), 8.0);
+    line.dash = Some(deckcraft_model::style::Dash::Preset { name: "dash".into() });
+    let img = render_slide(&picture_deck(Some(line)), 0, &RenderOpts { scale: 1.0, ..Default::default() });
+    assert!(close(img.pixel(120, 96), RED, 30) && close(img.pixel(140, 96), WHITE, 10), "{:?}", img.pixel(140, 96));
+}
+
+#[test]
+fn children_filled_with_the_group_fill_show_one_fill_across_the_group() {
+    use deckcraft_model::style::{Gradient, GradientShape, GradientStop};
+    let stops = vec![GradientStop { pos: 0.0, color: ColorRef::rgb(RED) }, GradientStop { pos: 1.0, color: ColorRef::rgb(Rgba::rgb(0, 0, 255)) }];
+    let grad =
+        Fill::Gradient(Gradient { tile: [0.0; 4], stops, shape: GradientShape::Linear { angle: 0.0, scaled: false }, rotate_with_shape: true });
+    let child = |id: u32, x: f64| Shape {
+        id: ShapeId(id),
+        xfrm: Some(Xfrm::new(x, 0.0, 90.0, 100.0)),
+        fill: Some(Fill::Group),
+        line: no_line(),
+        ..Default::default()
+    };
+    let g = Shape {
+        id: ShapeId(16),
+        xfrm: Some(Xfrm::new(100.0, 100.0, 200.0, 100.0)),
+        fill: Some(grad),
+        kind: ShapeKind::Group { children: vec![child(17, 0.0), child(18, 110.0)], child: Xfrm::new(0.0, 0.0, 200.0, 100.0) },
+        ..Default::default()
+    };
+    let img = render(vec![g]);
+    let (l, r) = (img.pixel(105, 150), img.pixel(295, 150));
+    assert!(l[0] > 200 && l[2] < 60, "left end of the group's gradient {l:?}");
+    assert!(r[2] > 200 && r[0] < 60, "right end {r:?}");
+    assert!(close(img.pixel(200, 150), WHITE, 5), "the gap between the children stays empty");
+}
+
+#[test]
+fn open_freeforms_take_arrowheads_even_when_filled() {
+    // An open custom path with a fill and a tail arrow: PowerPoint draws the arrow.
+    let end = deckcraft_model::style::LineEnd { kind: "triangle".into(), w: "med".into(), len: "med".into() };
+    let sh = Shape {
+        id: ShapeId(19),
+        xfrm: Some(Xfrm::new(100.0, 100.0, 200.0, 100.0)),
+        geom: Geom::Custom { paths: vec![CustomPath { w: 100.0, h: 100.0, d: "M 0 100 L 50 0 L 100 100".into(), ..Default::default() }] },
+        fill: solid(Rgba::rgb(0, 200, 0)),
+        line: Some(Line { fill: solid(RED), width: Some(4.0), tail: Some(end), ..Default::default() }),
+        ..Default::default()
+    };
+    let img = render(vec![sh]);
+    // The line ends at (300, 200) heading down-right at 45°; the 12 pt head's base corner reaches
+    // (295.7, 187.3), 3.5 pt off the line's axis: outside the 4 pt line and outside the fill.
+    assert!(close(img.pixel(294, 189), RED, 60), "arrowhead drawn {:?}", img.pixel(294, 189));
+}
+
+#[test]
+fn a_corner_radial_centres_on_the_corner_through_its_tile() {
+    // fillToRect on the top-left corner, tileRect reaching a whole box up and left: the circle is
+    // centred on the corner and reaches the far corner (as PowerPoint's "from corner" presets).
+    let mut sh = radial([0.0, 0.0, 1.0, 1.0]);
+    if let Some(Fill::Gradient(g)) = &mut sh.fill {
+        g.tile = [-1.0, -1.0, 0.0, 0.0];
+    }
+    let img = render(vec![sh]);
+    assert!(img.pixel(102, 102)[0] > 240, "white at the corner {:?}", img.pixel(102, 102));
+    let (top_right, bottom_left) = (img.pixel(498, 101)[0], img.pixel(101, 298)[0]);
+    assert!(top_right < bottom_left, "farther is darker {top_right} {bottom_left}");
+    assert!(bottom_left > 120, "the near edge stays light {bottom_left}");
+    assert!(img.pixel(497, 297)[0] < 40, "dark at the far corner {:?}", img.pixel(497, 297));
+}
+
+#[test]
+fn a_linear_gradient_spans_its_tile_rect() {
+    use deckcraft_model::style::{Gradient, GradientShape, GradientStop};
+    // Tile rect the left half of the box: the ramp ends half way and stays black after.
+    let stops = vec![GradientStop { pos: 0.0, color: ColorRef::rgb(WHITE) }, GradientStop { pos: 1.0, color: ColorRef::rgb(Rgba::BLACK) }];
+    let g = Gradient { stops, shape: GradientShape::Linear { angle: 0.0, scaled: false }, rotate_with_shape: true, tile: [0.0, 0.0, 0.5, 0.0] };
+    let sh = Shape {
+        id: ShapeId(20),
+        xfrm: Some(Xfrm::new(100.0, 100.0, 400.0, 100.0)),
+        fill: Some(Fill::Gradient(g)),
+        line: no_line(),
+        ..Default::default()
+    };
+    let img = render(vec![sh]);
+    assert!(img.pixel(102, 150)[0] > 240);
+    assert!(img.pixel(305, 150)[0] < 15 && img.pixel(495, 150)[0] < 15, "{:?}", img.pixel(305, 150));
+}
+
+#[test]
+fn a_3d_pictures_border_stays_centred_on_its_edge() {
+    let mut p = picture_deck(Some(Line::solid(ColorRef::rgb(RED), 8.0)));
+    let s = std::sync::Arc::make_mut(&mut p.slides[0]);
+    if let Some(sh) = s.shapes.first_mut() {
+        sh.effects = Some(deckcraft_model::Effects {
+            bevel: Some("circle".into()),
+            raw3d: Some("<a:scene3d><a:camera prst=\"orthographicFront\"/></a:scene3d><a:sp3d><a:bevelT/></a:sp3d>".into()),
+            ..Default::default()
+        });
+    }
+    let img = render_slide(&p, 0, &RenderOpts { scale: 1.0, ..Default::default() });
+    assert!(close(img.pixel(102, 150), RED, 30), "covers the picture's edge {:?}", img.pixel(102, 150));
+    assert!(close(img.pixel(94, 150), WHITE, 10), "reaches half the width out {:?}", img.pixel(94, 150));
+}
+
+#[allow(clippy::unwrap_used)]
+fn half_red_half_blue() -> Vec<u8> {
+    let img = image::RgbImage::from_fn(8, 4, |x, _| if x < 4 { image::Rgb([255, 0, 0]) } else { image::Rgb([0, 0, 255]) });
+    let mut out = std::io::Cursor::new(vec![]);
+    image::DynamicImage::ImageRgb8(img).write_to(&mut out, image::ImageFormat::Png).unwrap();
+    out.into_inner()
+}
+
+fn tiled(sx: f64, flip: &str, align: &str) -> Image {
+    use deckcraft_model::style::{PictureFill, PictureMode};
+    let mut p = Presentation::default();
+    let media = p.add_media("t.png", "image/png", half_red_half_blue());
+    let mode = PictureMode::Tile { tx: 0.0, ty: 0.0, sx, sy: 10.0, flip: flip.into(), align: align.into() };
+    let sh = Shape {
+        id: ShapeId(21),
+        xfrm: Some(Xfrm::new(100.0, 100.0, 240.0, 60.0)),
+        fill: Some(Fill::Picture(PictureFill { media, mode, ..Default::default() })),
+        line: no_line(),
+        ..Default::default()
+    };
+    std::sync::Arc::make_mut(&mut p.slides[0]).shapes = vec![sh];
+    render_slide(&p, 0, &RenderOpts { scale: 1.0, ..Default::default() })
+}
+
+#[test]
+fn tiled_pictures_flip_align_and_skip_non_positive_scales() {
+    let blue = Rgba::rgb(0, 0, 255);
+    // 8×4 px at 96 dpi scaled ten times: 60×30 pt tiles, red then blue, from the top-left.
+    let img = tiled(10.0, "none", "tl");
+    assert!(close(img.pixel(115, 115), RED, 30) && close(img.pixel(145, 115), blue, 30) && close(img.pixel(175, 115), RED, 30));
+    // Flipped across x: every other tile mirrored, so the second starts blue.
+    let img = tiled(10.0, "x", "tl");
+    assert!(close(img.pixel(145, 115), blue, 30) && close(img.pixel(175, 115), blue, 30) && close(img.pixel(205, 115), RED, 30));
+    // Aligned right: a tile ends at the box's right edge (340), so 310-340 is blue.
+    let img = tiled(10.0, "none", "r");
+    assert!(close(img.pixel(335, 130), blue, 30) && close(img.pixel(305, 130), RED, 30), "{:?}", img.pixel(305, 130));
+    // A negative scale draws nothing, as in PowerPoint.
+    let img = tiled(-10.0, "none", "tl");
+    assert!(close(img.pixel(115, 115), WHITE, 5) && close(img.pixel(300, 150), WHITE, 5));
+}
+
+#[test]
+fn a_tiles_first_copy_sits_on_the_point_its_alignment_names() {
+    let b = Rect::new(0.0, 0.0, 100.0, 50.0);
+    assert_eq!(paint::tile_origin(b, "tl", (20.0, 10.0), (0.0, 0.0)), Point::new(0.0, 0.0));
+    assert_eq!(paint::tile_origin(b, "ctr", (20.0, 10.0), (0.0, 0.0)), Point::new(40.0, 20.0));
+    assert_eq!(paint::tile_origin(b, "br", (20.0, 10.0), (5.0, -5.0)), Point::new(85.0, 35.0));
+    assert_eq!(paint::tile_origin(b, "nonsense", (20.0, 10.0), (f64::NAN, 1.0)), Point::new(0.0, 1.0));
+}
+
+/// `png` with a pHYs chunk saying `dpi` inserted after its header.
+fn with_dpi(png: &[u8], dpi: f64) -> Vec<u8> {
+    fn crc32(data: &[u8]) -> u32 {
+        let mut c = 0xFFFF_FFFFu32;
+        for b in data {
+            c ^= *b as u32;
+            for _ in 0..8 {
+                c = if c & 1 != 0 { 0xEDB8_8320 ^ (c >> 1) } else { c >> 1 };
+            }
+        }
+        !c
+    }
+    let ppm = (dpi / 0.0254).round() as u32;
+    let mut chunk = b"pHYs".to_vec();
+    chunk.extend_from_slice(&ppm.to_be_bytes());
+    chunk.extend_from_slice(&ppm.to_be_bytes());
+    chunk.push(1);
+    let mut out = png[..33].to_vec(); // signature (8) + IHDR chunk (25)
+    out.extend_from_slice(&9u32.to_be_bytes());
+    out.extend_from_slice(&chunk);
+    out.extend_from_slice(&crc32(&chunk).to_be_bytes());
+    out.extend_from_slice(&png[33..]);
+    out
+}
+
+#[test]
+fn picture_resolution_sizes_tiles() {
+    let png = half_red_half_blue();
+    assert_eq!(images::dpi(&png), None);
+    let p48 = with_dpi(&png, 48.0);
+    let d = images::dpi(&p48).unwrap_or_default();
+    assert!((d.0 - 48.0).abs() < 0.01 && (d.1 - 48.0).abs() < 0.01, "{d:?}");
+    // 8 × 4 px at 48 dpi is as big as 16 × 8 at 96.
+    assert_eq!(images::natural_size(&p48), Some((16.0, 8.0)));
+    assert_eq!(images::natural_size(&png), Some((8.0, 4.0)));
+    // JFIF density in dots per inch.
+    let mut jpeg = vec![0xFF, 0xD8, 0xFF, 0xE0, 0, 16];
+    jpeg.extend_from_slice(b"JFIF\0\x01\x01\x01\x00\x48\x00\x48");
+    assert_eq!(images::dpi(&jpeg), Some((72.0, 72.0)));
+}
+
+#[test]
+fn gradient_lines_and_their_heads_take_the_gradient() {
+    use deckcraft_model::style::{Gradient, GradientShape, GradientStop};
+    let blue = Rgba::rgb(0, 0, 255);
+    let grad = |angle: f64| {
+        Fill::Gradient(Gradient {
+            stops: vec![GradientStop { pos: 0.0, color: ColorRef::rgb(RED) }, GradientStop { pos: 1.0, color: ColorRef::rgb(blue) }],
+            shape: GradientShape::Linear { angle, scaled: false },
+            rotate_with_shape: true,
+            tile: [0.0; 4],
+        })
+    };
+    // Left to right along a 20 pt line: red at its start, blue at its end, and the arrowhead at
+    // the end blue too.
+    let mut sh = arrow_line("triangle", 20.0, RED);
+    if let Some(l) = &mut sh.line {
+        l.fill = Some(grad(0.0));
+    }
+    let img = render(vec![sh]);
+    let (start, mid, head) = (img.pixel(102, 100), img.pixel(200, 100), img.pixel(296, 100));
+    assert!(start[0] > 200 && start[2] < 60, "{start:?}");
+    assert!(mid[0] > 60 && mid[2] > 60, "{mid:?}");
+    assert!(head[2] > 200 && head[0] < 60, "head {head:?}");
+    // Top to bottom across a horizontal line: the gradient runs over the line's width.
+    let mut sh = arrow_line("none", 20.0, RED);
+    if let Some(l) = &mut sh.line {
+        l.fill = Some(grad(90.0));
+    }
+    let img = render(vec![sh]);
+    let (top, bottom) = (img.pixel(200, 91), img.pixel(200, 109));
+    assert!(top[0] > 200 && top[2] < 60 && bottom[2] > 200 && bottom[0] < 60, "{top:?} {bottom:?}");
+}
+
+#[test]
+fn a_groups_shadow_is_cast_by_its_children() {
+    let child = |id: u32, x: f64| Shape {
+        id: ShapeId(id),
+        xfrm: Some(Xfrm::new(x, 0.0, 80.0, 100.0)),
+        fill: solid(RED),
+        line: no_line(),
+        ..Default::default()
+    };
+    let g = Shape {
+        id: ShapeId(22),
+        xfrm: Some(Xfrm::new(100.0, 100.0, 200.0, 100.0)),
+        kind: ShapeKind::Group { children: vec![child(23, 0.0), child(24, 120.0)], child: Xfrm::new(0.0, 0.0, 200.0, 100.0) },
+        effects: Some(offset_shadow()),
+        ..Default::default()
+    };
+    let img = render(vec![g]);
+    // 20 pt to the right of each child: the shadow; in the gap only the left child's shadow shows.
+    assert!(close(img.pixel(190, 150), Rgba::BLACK, 30), "{:?}", img.pixel(190, 150));
+    assert!(close(img.pixel(210, 150), WHITE, 10), "{:?}", img.pixel(210, 150));
+    assert!(close(img.pixel(310, 150), Rgba::BLACK, 30), "{:?}", img.pixel(310, 150));
+    assert!(close(img.pixel(150, 150), RED, 10), "children drawn over it");
+}
+
+#[test]
+fn patterns_between_whole_pixel_cells_blend_neighbouring_cells() {
+    use deckcraft_model::style::PatternFill;
+    // narVert (alternate cells) at 0.75 output pixels per cell: PowerPoint's export reads
+    // 255, 128, 0 repeating across; drawing the nearest cell gave only black and white. Bilinear
+    // sampling gives about 213, 128, 42 (closer on average over all presets, not exact).
+    let g = |v: u8| ColorRef::rgb(Rgba::rgb(v, v, v));
+    let sh = Shape {
+        id: ShapeId(25),
+        xfrm: Some(Xfrm::new(0.0, 0.0, 60.0, 60.0)),
+        fill: Some(Fill::Pattern(PatternFill { preset: "narVert".into(), fg: g(0), bg: g(255) })),
+        line: no_line(),
+        ..Default::default()
+    };
+    let img = render(vec![sh]);
+    let row: Vec<u8> = (12..24).map(|x| img.pixel(x, 20)[0]).collect();
+    assert!(row.iter().any(|v| (100..=156).contains(v)), "a blended column: {row:?}");
+    assert!(row.iter().any(|v| *v < 60) && row.iter().any(|v| *v > 200), "{row:?}");
+    // The pattern repeats every 6 px (8 cells).
+    assert!(row.iter().zip(row.iter().skip(6)).all(|(a, b)| (*a as i32 - *b as i32).abs() <= 2), "{row:?}");
+}
+
+#[test]
+fn a_bevelled_shape_is_lit_from_the_upper_left() {
+    let base = Rgba::rgb(91, 155, 213);
+    let bevelled = |raw: &str| Shape {
+        id: ShapeId(26),
+        xfrm: Some(Xfrm::new(100.0, 100.0, 130.0, 130.0)),
+        fill: solid(base),
+        line: no_line(),
+        effects: Some(deckcraft_model::Effects { bevel: Some("circle".into()), raw3d: Some(raw.into()), ..Default::default() }),
+        ..Default::default()
+    };
+    let raw = r#"<a:scene3d><a:camera prst="orthographicFront"/><a:lightRig rig="threePt" dir="t"/></a:scene3d><a:sp3d><a:bevelT w="152400" h="76200"/></a:sp3d>"#;
+    let img = render(vec![bevelled(raw)]);
+    // PowerPoint: face (99, 166, 226); top of the band saturates, its bottom and right darken.
+    let face = img.pixel(165, 165);
+    assert!(close(face, Rgba::rgb(99, 166, 226), 8), "face {face:?}");
+    let (top, bottom, right) = (img.pixel(165, 104)[2], img.pixel(165, 226)[2], img.pixel(226, 165)[2]);
+    assert!(top > face[2] && bottom < face[2] && right < face[2], "top {top} bottom {bottom} right {right} face {}", face[2]);
+    // Without a 3-D scene PowerPoint draws it flat.
+    let img = render(vec![bevelled(r#"<a:sp3d><a:bevelT w="152400" h="76200"/></a:sp3d>"#)]);
+    assert!(close(img.pixel(165, 104), base, 2) && close(img.pixel(165, 165), base, 2));
+}
+
+#[test]
+fn table_borders_take_their_dashes_and_diagonals_are_drawn() {
+    let mut t = deckcraft_model::Table::new(1, 1, 200.0, 100.0);
+    t.style = "none".into();
+    let mut dashed = Line::solid(ColorRef::rgb(RED), 4.0);
+    dashed.dash = Some(deckcraft_model::style::Dash::Preset { name: "dash".into() });
+    if let Some(c) = t.rows.first_mut().and_then(|r| r.cells.first_mut()) {
+        c.borders[2] = Some(dashed);
+        c.diag_down = Some(Line::solid(ColorRef::rgb(Rgba::rgb(0, 0, 255)), 4.0));
+    }
+    let sh = Shape { id: ShapeId(27), xfrm: Some(Xfrm::new(100.0, 100.0, 200.0, 100.0)), kind: ShapeKind::Table(t), ..Default::default() };
+    let img = render(vec![sh]);
+    // Dashes of 4 widths (16 pt) on, 3 (12 pt) off along the top edge, from its start.
+    assert!(close(img.pixel(108, 100), RED, 40) && close(img.pixel(122, 100), WHITE, 30) && close(img.pixel(135, 100), RED, 40));
+    // The diagonal from top-left to bottom-right passes through the middle.
+    assert!(close(img.pixel(200, 150), Rgba::rgb(0, 0, 255), 40), "{:?}", img.pixel(200, 150));
+}
+
+#[test]
+fn a_large_pictures_shadow_is_whole() {
+    // A 400 px picture shown at 240 pt: its shadow was recoloured in the picture's pixel space and
+    // covered only part of it.
+    let mut counts = vec![];
+    for side in [8u32, 400] {
+        let mut p = Presentation::default();
+        let media = p.add_media("image1.png", "image/png", png(side, side * 3 / 4, [0, 0, 255]));
+        let mut fx = offset_shadow();
+        if let Some(o) = &mut fx.outer_shadow {
+            o.blur = 8.0;
+        }
+        let sh = Shape {
+            id: ShapeId(15),
+            xfrm: Some(Xfrm { rot: 20.0, ..Xfrm::new(360.0, 300.0, 240.0, 160.0) }),
+            kind: ShapeKind::Picture { fill: deckcraft_model::style::PictureFill { media, ..Default::default() } },
+            effects: Some(fx),
+            ..Default::default()
+        };
+        std::sync::Arc::make_mut(&mut p.slides[0]).shapes = vec![sh];
+        let img = render_slide(&p, 0, &RenderOpts { scale: 1.0, ..Default::default() });
+        counts.push(
+            (0..img.height)
+                .flat_map(|y| (0..img.width).map(move |x| (x, y)))
+                .filter(|(x, y)| {
+                    let q = img.pixel(*x, *y);
+                    q[0] < 200 && q[2] < 200
+                })
+                .count(),
+        );
+    }
+    assert!(counts[1] > 3000 && (counts[0] as i64 - counts[1] as i64).abs() < 300, "{counts:?}");
+}
+
+#[test]
+fn a_gradient_not_rotating_with_its_shape_keeps_to_the_slide() {
+    use deckcraft_model::style::{Gradient, GradientShape, GradientStop};
+    let blue = Rgba::rgb(0, 0, 255);
+    for rotate_with_shape in [true, false] {
+        let g = Gradient {
+            stops: vec![GradientStop { pos: 0.0, color: ColorRef::rgb(RED) }, GradientStop { pos: 1.0, color: ColorRef::rgb(blue) }],
+            shape: GradientShape::Linear { angle: 0.0, scaled: false },
+            rotate_with_shape,
+            tile: [0.0; 4],
+        };
+        // 200 × 100 turned a quarter: it covers 150..250 across and 50..250 down.
+        let sh = Shape {
+            id: ShapeId(28),
+            xfrm: Some(Xfrm { rot: 90.0, ..Xfrm::new(100.0, 100.0, 200.0, 100.0) }),
+            fill: Some(Fill::Gradient(g)),
+            line: no_line(),
+            ..Default::default()
+        };
+        let img = render(vec![sh]);
+        let (left, top) = (img.pixel(152, 150), img.pixel(200, 52));
+        if rotate_with_shape {
+            assert!(top[0] > 200 && top[2] < 60, "turned with the shape: red at the top {top:?}");
+        } else {
+            assert!(left[0] > 200 && left[2] < 60, "upright: red at the left {left:?}");
+            assert!(img.pixel(248, 150)[2] > 200, "blue at the right");
+        }
+    }
+}
+
+#[test]
+fn stars_and_right_arrows_have_sharp_corners_by_default() {
+    let shape = |name: &str, join: Option<deckcraft_model::style::LineJoin>| Shape {
+        id: ShapeId(29),
+        xfrm: Some(Xfrm::new(100.0, 100.0, 100.0, 100.0)),
+        geom: Geom::preset(name),
+        fill: solid(WHITE),
+        line: Some(Line { join, ..Line::solid(ColorRef::rgb(RED), 10.0) }),
+        ..Default::default()
+    };
+    // A star5's top point mitred reaches about 16 pt above the box; rounded only 5.
+    let img = render(vec![shape("star5", None)]);
+    assert!(close(img.pixel(150, 90), RED, 40), "mitred point {:?}", img.pixel(150, 90));
+    let img = render(vec![shape("star5", Some(deckcraft_model::style::LineJoin::Round))]);
+    assert!(close(img.pixel(150, 90), WHITE, 10), "an explicit round join stays round");
+    // A rectangle keeps PowerPoint's round default: its corner is cut round.
+    let img = render(vec![shape("rect", None)]);
+    assert!(close(img.pixel(95, 95), WHITE, 30), "{:?}", img.pixel(95, 95));
+    assert!(deckcraft_geom::preset::mitred_by_default("rightArrow") && !deckcraft_geom::preset::mitred_by_default("leftArrow"));
+}
+
+#[test]
+fn an_upright_picture_fill_stays_upright_in_a_turned_shape() {
+    use deckcraft_model::style::PictureFill;
+    let blue = Rgba::rgb(0, 0, 255);
+    for upright in [false, true] {
+        let mut p = Presentation::default();
+        let media = p.add_media("t.png", "image/png", half_red_half_blue());
+        // Half red (left) half blue picture in a 200 × 200 square turned a quarter (and so
+        // covering the same square).
+        let sh = Shape {
+            id: ShapeId(30),
+            xfrm: Some(Xfrm { rot: 90.0, ..Xfrm::new(100.0, 100.0, 200.0, 200.0) }),
+            fill: Some(Fill::Picture(PictureFill { media, upright, ..Default::default() })),
+            line: no_line(),
+            ..Default::default()
+        };
+        std::sync::Arc::make_mut(&mut p.slides[0]).shapes = vec![sh];
+        let img = render_slide(&p, 0, &RenderOpts { scale: 1.0, ..Default::default() });
+        let (left, top) = (img.pixel(110, 200), img.pixel(200, 110));
+        if upright {
+            assert!(close(left, RED, 30) && close(img.pixel(290, 200), blue, 30), "upright: red left {left:?}");
+        } else {
+            assert!(close(top, RED, 30), "turned with the shape: red at the top {top:?}");
+        }
+    }
+}
+
+#[test]
+fn a_picture_reflects_its_pixels() {
+    let mut p = picture_deck(None);
+    let s = std::sync::Arc::make_mut(&mut p.slides[0]);
+    if let Some(sh) = s.shapes.first_mut() {
+        let rf = deckcraft_model::style::Reflection { blur: 0.0, start_alpha: 1.0, end_alpha: 0.0, end_pos: 0.5, dist: 0.0 };
+        sh.effects = Some(deckcraft_model::Effects { reflection: Some(rf), ..Default::default() });
+    }
+    let img = render_slide(&p, 0, &RenderOpts { scale: 1.0, ..Default::default() });
+    // The blue picture spans 100..200 down; just below it, its reflection tints the page blue.
+    let below = img.pixel(200, 204);
+    assert!(below[2] > 200 && below[0] < 200, "{below:?}");
+    assert!(close(img.pixel(200, 290), WHITE, 10), "faded out by half its height");
+}
+
+#[test]
+fn a_3d_shapes_face_is_lit_even_without_a_bevel() {
+    let base = Rgba::rgb(237, 125, 49);
+    let shape = |raw: &str| Shape {
+        id: ShapeId(31),
+        xfrm: Some(Xfrm::new(100.0, 100.0, 150.0, 100.0)),
+        fill: solid(base),
+        line: no_line(),
+        effects: Some(deckcraft_model::Effects { raw3d: Some(raw.into()), ..Default::default() }),
+        ..Default::default()
+    };
+    // PowerPoint shows this face as about (251, 135, 56).
+    let img = render(vec![shape(r#"<a:scene3d><a:camera prst="orthographicFront"/><a:lightRig rig="threePt" dir="t"/></a:scene3d><a:sp3d/>"#)]);
+    assert!(close(img.pixel(175, 150), Rgba::rgb(248, 136, 60), 8), "{:?}", img.pixel(175, 150));
+    // No shape properties in 3-D: flat.
+    let img = render(vec![shape(r#"<a:scene3d><a:camera prst="orthographicFront"/><a:lightRig rig="threePt" dir="t"/></a:scene3d>"#)]);
+    assert!(close(img.pixel(175, 150), base, 1));
+}

crates/render/src/transition.rs

@@ -0,0 +1,517 @@
+//! Slide transition frames without a GPU: the layers of [`deckcraft_anim::transition_layers`]
+//! composited on the CPU from two rendered slide images. The slide show draws the same layers with
+//! the UI toolkit's meshes; this is the headless twin used by the CLI, comparisons and tests.
+
+use deckcraft_anim::{Layer, Source, layer_mesh, transition_frame, uses_slide_parts};
+use deckcraft_model::{Presentation, ShapeId};
+
+use crate::{Image, RenderOpts, ShapeState, SlidePart, render_blend, render_slide, render_slide_part};
+
+/// The two slides of a transition rendered as background and content, for the transitions that
+/// move contents over the backgrounds ([`deckcraft_anim::uses_slide_parts`]). `None` parts of the
+/// old slide (the show's first slide) are black and nothing.
+#[derive(Clone, Debug, Default)]
+pub struct SlideParts {
+    pub old_back: Option<Image>,
+    pub old_content: Option<Image>,
+    pub new_back: Image,
+    pub new_content: Image,
+}
+
+impl SlideParts {
+    /// Render the parts of slides `old` and `new`.
+    pub fn render(pres: &Presentation, old: Option<usize>, new: usize, opts: &RenderOpts) -> SlideParts {
+        SlideParts {
+            old_back: old.map(|i| render_slide_part(pres, i, SlidePart::Backdrop, opts)),
+            old_content: old.map(|i| render_slide_part(pres, i, SlidePart::Content, opts)),
+            new_back: render_slide_part(pres, new, SlidePart::Backdrop, opts),
+            new_content: render_slide_part(pres, new, SlidePart::Content, opts),
+        }
+    }
+}
+
+/// Composite transition `layers` over black into an image the size of `new`. `old` is the outgoing
+/// slide (`None`: black, as when the show starts); `parts` the slides' backgrounds and contents
+/// (without them, a background draws its whole slide and content draws nothing).
+pub fn composite_transition(old: Option<&Image>, new: &Image, parts: Option<&SlideParts>, layers: &[Layer]) -> Image {
+    let (w, h) = (new.width, new.height);
+    let n = (w as usize).saturating_mul(h as usize);
+    let mut out = Image { width: w, height: h, pixels: [0u8, 0, 0, 255].repeat(n) };
+    for l in layers {
+        let src = match (l.source.is_part(), parts) {
+            (true, None) => match l.source.whole() {
+                Some(s) => s,
+                None => continue,
+            },
+            _ => l.source,
+        };
+        let tex = match (src, parts) {
+            (Source::Old, _) => old.map(Tex::Image).unwrap_or(Tex::Solid([0.0, 0.0, 0.0])),
+            (Source::New, _) => Tex::Image(new),
+            (Source::Black, _) => Tex::Solid([0.0, 0.0, 0.0]),
+            (Source::White, _) => Tex::Solid([255.0, 255.0, 255.0]),
+            (Source::OldBack, Some(p)) => p.old_back.as_ref().map(Tex::Image).unwrap_or(Tex::Solid([0.0, 0.0, 0.0])),
+            (Source::NewBack, Some(p)) => Tex::Image(&p.new_back),
+            (Source::OldContent, Some(p)) => match &p.old_content {
+                Some(i) => Tex::Image(i),
+                None => continue,
+            },
+            (Source::NewContent, Some(p)) => Tex::Image(&p.new_content),
+            (_, None) => continue,
+        };
+        draw_layer(&mut out, l, &tex);
+    }
+    out
+}
+
+/// The frame of slide `index`'s transition at progress `t` (0..1): the previous slide (black for
+/// the first) going out, slide `index` coming in, at `opts`' scale and size. Morph frames are
+/// rendered shape by shape like the show does.
+pub fn render_transition(pres: &Presentation, index: usize, t: f64, opts: &RenderOpts) -> Image {
+    let Some(slide) = pres.slides.get(index) else { return Image::default() };
+    let (kind, option) = slide.transition.as_ref().map(|tr| (tr.kind.as_str(), tr.option.as_str())).unwrap_or(("none", ""));
+    let prev = index.checked_sub(1).filter(|i| pres.slides.get(*i).is_some());
+    if kind == "morph"
+        && let Some(from) = prev
+        && let Some(a) = pres.slides.get(from)
+    {
+        let tt = if t.is_finite() { t.clamp(0.0, 1.0) } else { 0.0 };
+        if tt < 1.0 {
+            let m = deckcraft_anim::morph_frame(pres, a, slide, tt, &|_| false);
+            let f = |id: ShapeId| ShapeState { opacity: m.opacity_of(id), ..Default::default() };
+            let o = RenderOpts { state: Some(&f), ..copy_opts(opts) };
+            let text: Vec<crate::TextMorph> =
+                m.text.iter().map(|x| crate::TextMorph { old: x.old, new: x.new, from: x.from, to: x.to, chars: x.chars, t: m.mix }).collect();
+            let paths: Vec<crate::PathMorph> = m
+                .paths
+                .iter()
+                .map(|x| crate::PathMorph { id: x.id, from: x.from.clone(), from_box: x.from_box, to_box: x.to_box, t: m.mix })
+                .collect();
+            return render_blend(pres, from, index, m.mix, &m.shapes, &text, &paths, &o);
+        }
+    }
+    let new = render_slide(pres, index, opts);
+    let old = prev.map(|i| render_slide(pres, i, opts));
+    let parts = uses_slide_parts(kind, option).then(|| SlideParts::render(pres, prev, index, opts));
+    let aspect = pres.slide_size.width / pres.slide_size.height.max(1.0);
+    composite_transition(old.as_ref(), &new, parts.as_ref(), &transition_frame(kind, option, t, aspect))
+}
+
+fn copy_opts<'a>(o: &RenderOpts<'a>) -> RenderOpts<'a> {
+    RenderOpts {
+        scale: o.scale,
+        edit: o.edit,
+        show_hidden: o.show_hidden,
+        state: o.state,
+        skip: o.skip,
+        skip_text: o.skip_text,
+        gif_times: o.gif_times,
+        threads: o.threads,
+        offset: o.offset,
+        size: o.size,
+        clear: o.clear,
+        date_text: o.date_text.clone(),
+        now: o.now,
+    }
+}
+
+enum Tex<'a> {
+    Image(&'a Image),
+    /// Straight RGB, opaque.
+    Solid([f32; 3]),
+}
+
+impl Tex<'_> {
+    /// Premultiplied RGBA (0..255) at texture coordinate (u, v), bilinear, clamped to the edge.
+    fn sample(&self, u: f64, v: f64) -> [f32; 4] {
+        match self {
+            Tex::Solid(c) => [c[0], c[1], c[2], 255.0],
+            Tex::Image(img) => {
+                let (w, h) = (img.width as usize, img.height as usize);
+                if w == 0 || h == 0 {
+                    return [0.0; 4];
+                }
+                let x = (u * w as f64 - 0.5).clamp(0.0, (w - 1) as f64);
+                let y = (v * h as f64 - 0.5).clamp(0.0, (h - 1) as f64);
+                let (x0, y0) = (x.floor() as usize, y.floor() as usize);
+                let (x1, y1) = ((x0 + 1).min(w - 1), (y0 + 1).min(h - 1));
+                let (fx, fy) = ((x - x0 as f64) as f32, (y - y0 as f64) as f32);
+                let px = |xx: usize, yy: usize| -> [f32; 4] {
+                    let i = (yy * w + xx) * 4;
+                    match img.pixels.get(i..i + 4) {
+                        Some(p) => [p[0] as f32, p[1] as f32, p[2] as f32, p[3] as f32],
+                        None => [0.0; 4],
+                    }
+                };
+                let (a, b, c, d) = (px(x0, y0), px(x1, y0), px(x0, y1), px(x1, y1));
+                let mut o = [0.0f32; 4];
+                for k in 0..4 {
+                    let top = a[k] + (b[k] - a[k]) * fx;
+                    let bot = c[k] + (d[k] - c[k]) * fx;
+                    o[k] = top + (bot - top) * fy;
+                }
+                o
+            }
+        }
+    }
+}
+
+fn draw_layer(out: &mut Image, l: &Layer, tex: &Tex) {
+    if !(l.alpha.is_finite() && l.alpha > 0.0) {
+        return;
+    }
+    let (verts, tris) = layer_mesh(l);
+    let (w, h) = (out.width as f64, out.height as f64);
+    for t in tris {
+        let (Some(a), Some(b), Some(c)) = (verts.get(t[0] as usize), verts.get(t[1] as usize), verts.get(t[2] as usize)) else { continue };
+        let p = [[a.pos[0] * w, a.pos[1] * h], [b.pos[0] * w, b.pos[1] * h], [c.pos[0] * w, c.pos[1] * h]];
+        let uv = [a.uv, b.uv, c.uv];
+        let al = [a.a, b.a, c.a].map(|x| if x.is_finite() { x.clamp(0.0, 1.0) } else { 0.0 });
+        if al.iter().all(|x| *x <= 0.0) {
+            continue;
+        }
+        fill_triangle(out, p, uv, al, tex);
+    }
+}
+
+/// Rasterise one textured triangle: pixel centres inside it take the texture's colour at the
+/// barycentric texture coordinate, at the interpolated opacity, blended source-over.
+fn fill_triangle(out: &mut Image, p: [[f64; 2]; 3], uv: [[f64; 2]; 3], al: [f64; 3], tex: &Tex) {
+    let area = (p[1][0] - p[0][0]) * (p[2][1] - p[0][1]) - (p[2][0] - p[0][0]) * (p[1][1] - p[0][1]);
+    if !area.is_finite() || area.abs() < 1e-12 {
+        return;
+    }
+    let (w, h) = (out.width as i64, out.height as i64);
+    let minx = p.iter().map(|q| q[0]).fold(f64::INFINITY, f64::min).floor().max(0.0) as i64;
+    let maxx = (p.iter().map(|q| q[0]).fold(f64::NEG_INFINITY, f64::max).ceil() as i64).min(w);
+    let miny = p.iter().map(|q| q[1]).fold(f64::INFINITY, f64::min).floor().max(0.0) as i64;
+    let maxy = (p.iter().map(|q| q[1]).fold(f64::NEG_INFINITY, f64::max).ceil() as i64).min(h);
+    if minx >= maxx || miny >= maxy {
+        return;
+    }
+    let edge = |a: [f64; 2], b: [f64; 2], x: f64, y: f64| (b[0] - a[0]) * (y - a[1]) - (b[1] - a[1]) * (x - a[0]);
+    let width = out.width as usize;
+    for y in miny..maxy {
+        // Sample a hair off the pixel centre so a point on an edge shared by two triangles falls
+        // in exactly one of them (no double-blended seams).
+        let fy = y as f64 + 0.5 + 2.31e-6;
+        for x in minx..maxx {
+            let fx = x as f64 + 0.5 + 1.17e-6;
+            let w0 = edge(p[1], p[2], fx, fy) / area;
+            let w1 = edge(p[2], p[0], fx, fy) / area;
+            let w2 = edge(p[0], p[1], fx, fy) / area;
+            if w0 < 0.0 || w1 < 0.0 || w2 < 0.0 {
+                continue;
+            }
+            let u = w0 * uv[0][0] + w1 * uv[1][0] + w2 * uv[2][0];
+            let v = w0 * uv[0][1] + w1 * uv[1][1] + w2 * uv[2][1];
+            let alpha = (w0 * al[0] + w1 * al[1] + w2 * al[2]) as f32;
+            if alpha <= 0.0 {
+                continue;
+            }
+            let s = tex.sample(u, v);
+            let i = (y as usize * width + x as usize) * 4;
+            let Some(d) = out.pixels.get_mut(i..i + 4) else { continue };
+            let sa = s[3] * alpha / 255.0;
+            for k in 0..4 {
+                let src = s[k] * alpha;
+                let v = src + d[k] as f32 * (1.0 - sa);
+                d[k] = v.round().clamp(0.0, 255.0) as u8;
+            }
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn solid(w: u32, h: u32, c: [u8; 4]) -> Image {
+        Image { width: w, height: h, pixels: c.repeat((w * h) as usize) }
+    }
+
+    #[test]
+    fn layers_composite_in_order() {
+        let old = solid(40, 20, [255, 0, 0, 255]);
+        let new = solid(40, 20, [0, 0, 255, 255]);
+        let img = composite_transition(Some(&old), &new, None, &deckcraft_anim::transition_layers("cover", "l", 0.0));
+        assert_eq!(img.pixel(20, 10), [255, 0, 0, 255]);
+        let img = composite_transition(Some(&old), &new, None, &deckcraft_anim::transition_layers("cover", "l", 1.0));
+        assert_eq!(img.pixel(20, 10), [0, 0, 255, 255]);
+    }
+
+    #[test]
+    fn missing_old_slide_is_black() {
+        let new = solid(10, 10, [0, 255, 0, 255]);
+        let img = composite_transition(None, &new, None, &[Layer::full(Source::Old, 1.0)]);
+        assert_eq!(img.pixel(5, 5), [0, 0, 0, 255]);
+    }
+
+    #[test]
+    fn half_alpha_blends() {
+        let old = solid(10, 10, [200, 0, 0, 255]);
+        let new = solid(10, 10, [0, 0, 200, 255]);
+        let l = [Layer::full(Source::Old, 1.0), Layer::full(Source::New, 0.5)];
+        let p = composite_transition(Some(&old), &new, None, &l).pixel(5, 5);
+        assert!((p[0] as i32 - 100).abs() <= 1 && (p[2] as i32 - 100).abs() <= 1, "{p:?}");
+    }
+
+    // ---------- golden-ish frames on synthetic slides ----------
+
+    const W: u32 = 160;
+    const H: u32 = 90;
+    const OLD: [u8; 4] = [220, 40, 40, 255];
+    const NEW: [u8; 4] = [30, 60, 200, 255];
+
+    #[derive(Clone, Copy, Debug, PartialEq)]
+    enum Is {
+        Old,
+        New,
+        Black,
+        White,
+        /// Something between (a blend).
+        Mix,
+    }
+
+    fn classify(p: [u8; 4]) -> Is {
+        let d = |c: [u8; 4]| (p[0] as i32 - c[0] as i32).abs() + (p[1] as i32 - c[1] as i32).abs() + (p[2] as i32 - c[2] as i32).abs();
+        let near = 40;
+        if d(OLD) < near {
+            Is::Old
+        } else if d(NEW) < near {
+            Is::New
+        } else if d([0, 0, 0, 255]) < near {
+            Is::Black
+        } else if d([255, 255, 255, 255]) < near {
+            Is::White
+        } else {
+            // A face shaded in 3-D: a darker copy of one of the slides.
+            let shaded = |c: [u8; 4]| {
+                let dot = |a: [u8; 4], b: [u8; 4]| (0..3).map(|i| a[i] as f64 * b[i] as f64).sum::<f64>();
+                let k = dot(p, c) / dot(c, c);
+                (0.3..=1.05).contains(&k) && (0..3).all(|i| (p[i] as f64 - k * c[i] as f64).abs() < 14.0)
+            };
+            if shaded(OLD) {
+                Is::Old
+            } else if shaded(NEW) {
+                Is::New
+            } else {
+                Is::Mix
+            }
+        }
+    }
+
+    fn frame(kind: &str, option: &str, t: f64) -> Image {
+        let old = solid(W, H, OLD);
+        let new = solid(W, H, NEW);
+        composite_transition(Some(&old), &new, None, &transition_frame(kind, option, t, 16.0 / 9.0))
+    }
+
+    fn at(img: &Image, x: f64, y: f64) -> Is {
+        let px = ((x * W as f64) as u32).min(W - 1);
+        let py = ((y * H as f64) as u32).min(H - 1);
+        classify(img.pixel(px, py))
+    }
+
+    /// (kind, option, t, x, y, what PowerPoint shows there), read off PowerPoint's own frames.
+    const PROBES: &[(&str, &str, f64, f64, f64, Is)] = &[
+        ("fade", "smoothly", 0.1, 0.5, 0.5, Is::Old),
+        ("fade", "smoothly", 0.5, 0.5, 0.5, Is::Mix),
+        ("fade", "smoothly", 0.9, 0.5, 0.5, Is::New),
+        ("fade", "throughBlack", 0.5, 0.5, 0.5, Is::Black),
+        ("cut", "throughBlack", 0.3, 0.5, 0.5, Is::Black),
+        ("cut", "", 0.3, 0.5, 0.5, Is::New),
+        // Push / Cover / Uncover: "l" moves things toward the left; the new slide comes from the right.
+        ("push", "l", 0.25, 0.97, 0.5, Is::New),
+        ("push", "l", 0.25, 0.1, 0.5, Is::Old),
+        ("push", "r", 0.25, 0.03, 0.5, Is::New),
+        ("push", "u", 0.25, 0.5, 0.97, Is::New),
+        ("push", "d", 0.25, 0.5, 0.03, Is::New),
+        ("cover", "l", 0.5, 0.75, 0.5, Is::New),
+        ("cover", "l", 0.5, 0.25, 0.5, Is::Old),
+        ("cover", "rd", 0.5, 0.05, 0.05, Is::New),
+        ("cover", "rd", 0.2, 0.97, 0.97, Is::Old),
+        ("uncover", "l", 0.5, 0.25, 0.5, Is::Old),
+        ("uncover", "l", 0.5, 0.75, 0.5, Is::New),
+        ("uncover", "lu", 0.5, 0.5, 0.5, Is::New),
+        // Wipe "r" sweeps rightward with a soft edge; "u" upward; diagonals from a corner.
+        ("wipe", "r", 0.5, 0.05, 0.5, Is::New),
+        ("wipe", "r", 0.5, 0.97, 0.5, Is::Old),
+        ("wipe", "l", 0.5, 0.97, 0.5, Is::New),
+        ("wipe", "u", 0.5, 0.5, 0.97, Is::New),
+        ("wipe", "u", 0.5, 0.5, 0.03, Is::Old),
+        ("wipe", "d", 0.5, 0.5, 0.03, Is::New),
+        ("wipe", "ru", 0.5, 0.03, 0.97, Is::New),
+        ("wipe", "ru", 0.5, 0.97, 0.03, Is::Old),
+        ("wipe", "r", 0.5, 0.55, 0.5, Is::Mix),
+        // Split: Out opens from the middle, In closes from the edges.
+        ("split", "horzOut", 0.5, 0.5, 0.5, Is::New),
+        ("split", "horzOut", 0.5, 0.5, 0.02, Is::Old),
+        ("split", "horzIn", 0.5, 0.5, 0.02, Is::New),
+        ("split", "horzIn", 0.5, 0.5, 0.5, Is::Old),
+        ("split", "vertOut", 0.5, 0.5, 0.5, Is::New),
+        ("split", "vertOut", 0.5, 0.02, 0.5, Is::Old),
+        ("split", "vertIn", 0.5, 0.02, 0.5, Is::New),
+        // Shape: grows from the centre; In shrinks the old slide over the first half, Out grows
+        // the new one over the second.
+        ("shape", "circle", 0.5, 0.5, 0.5, Is::New),
+        ("shape", "circle", 0.5, 0.02, 0.03, Is::Old),
+        ("shape", "diamond", 0.5, 0.5, 0.5, Is::New),
+        ("shape", "diamond", 0.5, 0.02, 0.03, Is::Old),
+        ("shape", "plus", 0.5, 0.5, 0.05, Is::New),
+        ("shape", "plus", 0.5, 0.05, 0.05, Is::Old),
+        ("shape", "in", 0.25, 0.5, 0.5, Is::Old),
+        ("shape", "in", 0.25, 0.05, 0.05, Is::New),
+        ("shape", "in", 0.75, 0.5, 0.5, Is::New),
+        ("shape", "out", 0.25, 0.5, 0.5, Is::Old),
+        ("shape", "out", 0.75, 0.5, 0.5, Is::New),
+        ("shape", "out", 0.75, 0.05, 0.05, Is::Old),
+        // Flash: white in the middle.
+        ("flash", "", 0.3, 0.5, 0.5, Is::White),
+        // Clock: a hand sweeping from 12 o'clock.
+        ("clock", "clockwise", 0.25, 0.6, 0.15, Is::New),
+        ("clock", "clockwise", 0.25, 0.4, 0.15, Is::Old),
+        ("clock", "counterClockwise", 0.25, 0.4, 0.15, Is::New),
+        ("clock", "counterClockwise", 0.25, 0.6, 0.15, Is::Old),
+        ("clock", "wedge", 0.5, 0.5, 0.05, Is::New),
+        ("clock", "wedge", 0.5, 0.5, 0.95, Is::Old),
+        // Ripple: from the centre, or from the corner opposite the option.
+        ("ripple", "center", 0.5, 0.5, 0.5, Is::New),
+        ("ripple", "center", 0.5, 0.02, 0.03, Is::Old),
+        ("ripple", "ru", 0.4, 0.03, 0.97, Is::New),
+        ("ripple", "ru", 0.4, 0.97, 0.03, Is::Old),
+        // Comb: the old slide's bands slide off, the bottom band first.
+        ("comb", "horz", 0.5, 0.5, 0.97, Is::New),
+        ("comb", "horz", 0.5, 0.5, 0.03, Is::Old),
+        // Glitter "l": the sweep starts on the left.
+        ("glitter", "l", 0.45, 0.03, 0.5, Is::New),
+        ("glitter", "l", 0.45, 0.97, 0.5, Is::Old),
+        ("glitter", "r", 0.45, 0.97, 0.5, Is::New),
+        // Vortex "l": the old slide whirls off toward the left, its right side first.
+        ("vortex", "l", 0.25, 0.03, 0.5, Is::Old),
+        ("vortex", "l", 0.97, 0.03, 0.5, Is::New),
+        // Cube / Box "l": the new face comes in from the right.
+        ("cube", "l", 0.5, 0.85, 0.5, Is::New),
+        ("cube", "l", 0.5, 0.15, 0.5, Is::Old),
+        ("cube", "r", 0.5, 0.15, 0.5, Is::New),
+        ("box", "l", 0.25, 0.97, 0.5, Is::New),
+        ("box", "l", 0.25, 0.3, 0.5, Is::Old),
+        ("cube", "u", 0.5, 0.5, 0.9, Is::New),
+        ("cube", "d", 0.5, 0.5, 0.1, Is::New),
+        // Switch "l": the old card is pulled out to the left, the new one to the right.
+        ("switch", "l", 0.25, 0.97, 0.5, Is::New),
+        ("switch", "l", 0.25, 0.3, 0.5, Is::Old),
+        ("switch", "r", 0.25, 0.03, 0.5, Is::New),
+        // Gallery "l": the slides travel left along the wall.
+        ("gallery", "l", 0.6, 0.9, 0.5, Is::New),
+        // Flip: the old face, then the new one.
+        ("flip", "l", 0.2, 0.5, 0.5, Is::Old),
+        ("flip", "l", 0.8, 0.5, 0.5, Is::New),
+        // Doors open in the middle, the new slide coming forward between them.
+        ("doors", "vert", 0.9, 0.5, 0.5, Is::New),
+        // Fall Over: the old slide tips backward, uncovering the new one at the top first.
+        ("fallOver", "l", 0.6, 0.5, 0.03, Is::New),
+        ("fallOver", "l", 0.6, 0.5, 0.97, Is::Old),
+        // Peel Off "l": from the bottom-right corner.
+        ("peelOff", "l", 0.4, 0.98, 0.98, Is::New),
+        ("peelOff", "l", 0.4, 0.03, 0.03, Is::Old),
+        ("peelOff", "r", 0.4, 0.02, 0.98, Is::New),
+        // Page Curl: the far half rolls up first.
+        ("pageCurlDouble", "l", 0.5, 0.9, 0.5, Is::New),
+        ("pageCurlDouble", "l", 0.5, 0.1, 0.5, Is::Old),
+        ("pageCurlDouble", "r", 0.5, 0.1, 0.5, Is::New),
+        ("pageCurlDouble", "singleL", 0.6, 0.95, 0.5, Is::New),
+        ("pageCurlDouble", "singleL", 0.6, 0.05, 0.5, Is::Old),
+        // Airplane "l": a dart with its nose to the right, hanging low.
+        ("airplane", "l", 0.5, 0.15, 0.1, Is::New),
+        ("airplane", "l", 0.5, 0.8, 0.68, Is::Old),
+        ("airplane", "r", 0.5, 0.2, 0.68, Is::Old),
+        // Origami "l": the bird flies off to the left.
+        ("origami", "l", 0.75, 0.97, 0.5, Is::New),
+        // Fracture: shards fall, the top first.
+        ("fracture", "", 0.6, 0.5, 0.05, Is::New),
+        // Crush: the old slide crumples toward the centre.
+        ("crush", "", 0.5, 0.03, 0.03, Is::New),
+        ("crush", "", 0.5, 0.45, 0.5, Is::Old),
+        // Curtains part in the middle.
+        ("curtains", "", 0.4, 0.5, 0.5, Is::New),
+        ("curtains", "", 0.4, 0.02, 0.5, Is::Old),
+        // Zoom and Rotate: the new slide spins in from the centre over the old one.
+        ("zoom", "rotate", 0.2, 0.03, 0.03, Is::Old),
+        ("zoom", "out", 0.8, 0.5, 0.5, Is::New),
+        ("dissolve", "", 0.02, 0.5, 0.5, Is::Old),
+        ("dissolve", "", 0.99, 0.5, 0.5, Is::New),
+    ];
+
+    #[test]
+    fn frames_match_powerpoint_probes() {
+        let mut bad = Vec::new();
+        for (kind, option, t, x, y, want) in PROBES {
+            let got = at(&frame(kind, option, *t), *x, *y);
+            if got != *want {
+                bad.push(format!("{kind}/{option} t={t} ({x},{y}): want {want:?}, got {got:?}"));
+            }
+        }
+        assert!(bad.is_empty(), "{}", bad.join("\n"));
+    }
+
+    #[test]
+    fn every_transition_starts_old_and_ends_new() {
+        for (kind, _, _, _, opts) in deckcraft_model::anim::TRANSITIONS {
+            let mut options: Vec<&str> = opts.to_vec();
+            options.push("");
+            for o in options {
+                assert_eq!(at(&frame(kind, o, 0.0), 0.5, 0.5), Is::Old, "{kind}/{o}");
+                assert_eq!(at(&frame(kind, o, 1.0), 0.5, 0.5), Is::New, "{kind}/{o}");
+                for t in [0.25, 0.5, 0.75] {
+                    let img = frame(kind, o, t);
+                    assert_eq!((img.width, img.height), (W, H));
+                }
+            }
+        }
+    }
+
+    #[test]
+    fn dynamic_content_moves_contents_over_backgrounds() {
+        // Old: red background with a white content square in the middle; new: blue background
+        // with a yellow square.
+        let content = |c: [u8; 4]| {
+            let mut img = solid(W, H, [0, 0, 0, 0]);
+            for y in 35..55u32 {
+                for x in 70..90u32 {
+                    let i = ((y * W + x) * 4) as usize;
+                    if let Some(p) = img.pixels.get_mut(i..i + 4) {
+                        p.copy_from_slice(&c);
+                    }
+                }
+            }
+            img
+        };
+        let parts = SlideParts {
+            old_back: Some(solid(W, H, OLD)),
+            old_content: Some(content([255, 255, 255, 255])),
+            new_back: solid(W, H, NEW),
+            new_content: content([255, 220, 0, 255]),
+        };
+        let old = solid(W, H, OLD);
+        let new = solid(W, H, NEW);
+        let f = |kind: &str, o: &str, t: f64| composite_transition(Some(&old), &new, Some(&parts), &transition_frame(kind, o, t, 16.0 / 9.0));
+        // Pan left at the middle: the backgrounds blend, the old square has moved left.
+        let img = f("pan", "l", 0.5);
+        let bg = img.pixel(5, 5);
+        assert!(bg[0] > 60 && bg[2] > 60, "{bg:?}");
+        assert_eq!(img.pixel(80, 45), bg, "the middle shows background only");
+        // Pan right: the new square arrives from the left.
+        let img = f("pan", "r", 0.6);
+        assert!((0..80).any(|x| {
+            let p = img.pixel(x, 45);
+            p[0] > 200 && p[1] > 180 && p[2] < 80
+        }));
+        // Reveal: the new content is in place near the end.
+        let p = f("reveal", "smoothlyLeft", 0.97).pixel(80, 45);
+        assert!(p[0] > 200 && p[1] > 180, "{p:?}");
+        // Without parts the dynamic transitions still draw whole slides.
+        let img = composite_transition(Some(&old), &new, None, &transition_frame("pan", "l", 0.5, 16.0 / 9.0));
+        assert_ne!(img.pixel(80, 45), [0, 0, 0, 255]);
+    }
+}

crates/render/src/warp.rs

@@ -140,10 +140,12 @@ pub(crate) fn draw(ctx: &mut RenderContext, l: &TextLayout, tr: Rect, m: Affine,
         }
         let y = (d.rect.y0 + d.rect.y1) / 2.0;
         let Some(li) = line_of(l, d.para, y) else { return };
-        let path = warp_path(&d.rect.to_path(0.1), tol, seg, &|p| mapper.map(li, p));
         ctx.set_transform(m * Affine::translate(ps.offset));
         ctx.set_paint(color(d.color, ps.opacity));
-        ctx.fill_path(&path);
+        for r in d.pieces() {
+            let path = warp_path(&r.to_path(0.1), tol, seg, &|p| mapper.map(li, p));
+            ctx.fill_path(&path);
+        }
     };
     for d in l.decos.iter().filter(|d| d.behind) {
         deco(ctx, d);

crates/text/src/bidi.rs

@@ -6,7 +6,7 @@
 //! [`visual_order`] rule L2). Rule L4 (mirrored brackets) is applied by the shaper, which draws
 //! mirrorable characters in right-to-left items with their mirrored glyphs.
 
-use unicode_bidi::BidiClass::{self, AL, AN, B, BN, FSI, LRE, LRI, LRO, PDF, PDI, R, RLE, RLI, RLO, S, WS};
+use unicode_bidi::BidiClass::{self, AL, AN, B, BN, CS, EN, ES, ET, FSI, L, LRE, LRI, LRO, NSM, ON, PDF, PDI, R, RLE, RLI, RLO, S, WS};
 use unicode_bidi::{BidiInfo, Level, bidi_class};
 
 /// Does anything in the text need the full algorithm? (Strong right-to-left, Arabic numbers or
@@ -27,6 +27,149 @@ pub(crate) fn levels(text: &str, chars: &[char], rtl: bool) -> Vec<u8> {
     text.char_indices().map(|(b, _)| info.levels.get(b).map(|l| l.number()).unwrap_or(base)).collect()
 }
 
+/// Is `lang` (BCP 47) a language written right to left? Its runs resolve neutral characters and
+/// digits the right-to-left way (see [`levels_lang`]).
+pub(crate) fn is_rtl_lang(lang: &str) -> bool {
+    let primary = lang.split(['-', '_']).next().unwrap_or("").to_ascii_lowercase();
+    matches!(primary.as_str(), "ar" | "he" | "iw" | "fa" | "ur" | "yi" | "ji" | "ps" | "sd" | "ug" | "dv" | "syr" | "ckb" | "arc")
+}
+
+/// How a character resolves before levels are assigned.
+#[derive(Clone, Copy, PartialEq, Eq, Debug)]
+enum Dir {
+    L,
+    R,
+    /// A number inside right-to-left text: kept left to right, placed with the right-to-left text.
+    Num,
+    /// Not resolved yet (neutral).
+    Open,
+}
+
+/// Embedding levels as PowerPoint resolves them: the language of each character's run
+/// (`rtl_lang`, from `a:rPr/@lang`) decides how neutral characters and digits go, where UAX #9
+/// would look at the surrounding text only. Observed on desktop PowerPoint:
+/// - in a run of a left-to-right language (or none), digits and punctuation are left to right,
+///   and a space takes the direction of the character before it (so the space after a Hebrew word
+///   travels with that word);
+/// - in a run of a right-to-left language (Hebrew, Arabic…), punctuation and spaces between text
+///   of one direction take it, everywhere else they are right to left; digits are a number in
+///   right-to-left text unless left-to-right text precedes them.
+///
+/// Paragraphs with explicit embeddings or isolates keep the plain algorithm ([`levels`]).
+pub(crate) fn levels_lang(text: &str, chars: &[char], rtl: bool, rtl_lang: &[bool]) -> Vec<u8> {
+    let base = u8::from(rtl);
+    let any_rtl_lang = rtl_lang.iter().any(|r| *r);
+    if !rtl && !any_rtl_lang && !needs_bidi(chars) {
+        return vec![0; chars.len()];
+    }
+    let classes: Vec<BidiClass> = chars.iter().map(|c| bidi_class(*c)).collect();
+    if classes.iter().any(|c| matches!(c, LRE | RLE | LRO | RLO | PDF | LRI | RLI | FSI | PDI)) {
+        return levels(text, chars, rtl);
+    }
+    let n = chars.len();
+    let rl = |i: usize| rtl_lang.get(i).copied().unwrap_or(false);
+    let sos = if rtl { Dir::R } else { Dir::L };
+    // W1: combining marks take the class of the character they sit on.
+    let mut cls = classes;
+    for i in 0..n {
+        if cls.get(i) == Some(&NSM) {
+            let prev = if i == 0 { if rtl { R } else { L } } else { cls.get(i - 1).copied().unwrap_or(L) };
+            if let Some(c) = cls.get_mut(i) {
+                *c = prev;
+            }
+        }
+    }
+    let mut dir = vec![Dir::Open; n];
+    // Strong letters and digits.
+    let mut last_strong: Option<BidiClass> = None;
+    for i in 0..n {
+        let c = cls.get(i).copied().unwrap_or(ON);
+        let d = match c {
+            L => Dir::L,
+            R | AL => Dir::R,
+            AN => Dir::Num,
+            EN if !rl(i) => Dir::L,
+            // W7: European digits after left-to-right text are left to right.
+            EN if last_strong == Some(L) => Dir::L,
+            EN => Dir::Num,
+            _ => Dir::Open,
+        };
+        if matches!(c, L | R | AL) {
+            last_strong = Some(c);
+        }
+        if let Some(x) = dir.get_mut(i) {
+            *x = d;
+        }
+    }
+    // W4/W5 in right-to-left runs: a separator between digits, and currency or percent signs next
+    // to them, belong to the number.
+    for i in 0..n {
+        if !rl(i) || dir.get(i) != Some(&Dir::Open) {
+            continue;
+        }
+        let c = cls.get(i).copied().unwrap_or(ON);
+        let num = |j: Option<usize>| j.and_then(|j| dir.get(j)).is_some_and(|d| *d == Dir::Num);
+        let joined = match c {
+            ES | CS => num(i.checked_sub(1)) && num(Some(i + 1)),
+            ET => num(i.checked_sub(1)) || (i + 1..n).find(|&j| cls.get(j) != Some(&ET)).is_some_and(|j| num(Some(j))),
+            _ => false,
+        };
+        if joined && let Some(x) = dir.get_mut(i) {
+            *x = Dir::Num;
+        }
+    }
+    // Punctuation in left-to-right runs is left to right.
+    for i in 0..n {
+        if !rl(i)
+            && dir.get(i) == Some(&Dir::Open)
+            && !matches!(cls.get(i), Some(WS | S))
+            && let Some(x) = dir.get_mut(i)
+        {
+            *x = Dir::L;
+        }
+    }
+    // Neutrals in right-to-left runs: the direction around them when both sides agree, else
+    // right to left. Unresolved spaces of left-to-right runs are looked through.
+    let strong_at = |dir: &[Dir], j: usize| match dir.get(j) {
+        Some(Dir::L) => Some(Dir::L),
+        Some(Dir::R | Dir::Num) => Some(Dir::R),
+        _ => None,
+    };
+    let mut i = 0;
+    while i < n {
+        if !(rl(i) && dir.get(i) == Some(&Dir::Open)) {
+            i += 1;
+            continue;
+        }
+        let start = i;
+        while i < n && rl(i) && dir.get(i) == Some(&Dir::Open) {
+            i += 1;
+        }
+        let before = (0..start).rev().find_map(|j| strong_at(&dir, j)).unwrap_or(sos);
+        let after = (i..n).find_map(|j| strong_at(&dir, j)).unwrap_or(sos);
+        let d = if before == after { before } else { Dir::R };
+        for x in dir.get_mut(start..i).into_iter().flatten() {
+            *x = d;
+        }
+    }
+    // Spaces in left-to-right runs follow the character before them.
+    let mut prev = Dir::L;
+    for d in dir.iter_mut() {
+        if *d == Dir::Open {
+            *d = prev;
+        }
+        prev = if *d == Dir::Num { Dir::R } else { *d };
+    }
+    dir.iter()
+        .map(|d| match (d, base % 2 == 1) {
+            (Dir::L, false) | (Dir::R, true) => base,
+            (Dir::L, true) | (Dir::R, false) | (Dir::Open, _) => base + 1,
+            (Dir::Num, false) => base + 2,
+            (Dir::Num, true) => base + 1,
+        })
+        .collect()
+}
+
 /// Whitespace-like for rule L1: reset to the paragraph level when trailing a line or preceding a
 /// segment/paragraph separator.
 fn l1_whitespace(c: BidiClass) -> bool {
@@ -131,6 +274,40 @@ mod tests {
         assert_eq!(lv("ab", true), vec![2, 2]);
     }
 
+    /// Visual string of `s` laid out on one line with every character in a run of language
+    /// direction `rtl_lang`, as PowerPoint orders it.
+    fn vis_lang(s: &str, rtl: bool, rtl_lang: bool) -> String {
+        let chars: Vec<char> = s.chars().collect();
+        let l = levels_lang(s, &chars, rtl, &vec![rtl_lang; chars.len()]);
+        visual_order(&line_levels(&chars, &l, u8::from(rtl))).iter().map(|&i| chars[i]).collect()
+    }
+
+    #[test]
+    fn run_language_decides_neutrals_like_powerpoint() {
+        // Observed in PowerPoint with each space highlighted. An English run: the space after a
+        // Hebrew word goes with it, punctuation is left to right.
+        assert_eq!(vis_lang("x אב גד y", false, false), "x  דג באy");
+        assert_eq!(vis_lang("אב גד x y", false, false), " דג באx y");
+        assert_eq!(vis_lang("x אב, גד! y", false, false), "x בא, דג! y");
+        // Digits after Hebrew stay left to right in an English run.
+        assert_eq!(vis_lang("אב 12", false, false), " בא12");
+        // A Hebrew run: neutrals between different directions are right to left, and digits are
+        // a number inside the right-to-left text.
+        assert_eq!(vis_lang("אב גד x y", false, true), " דג באx y");
+        assert_eq!(vis_lang("12 אב 34 x", false, true), " 34 בא 12x");
+        assert_eq!(vis_lang("x אב, גד! y", false, true), "x !דג ,בא y");
+        // Between two left-to-right words a Hebrew run's space stays left to right.
+        assert_eq!(vis_lang("Version 2.0 ok", false, true), "Version 2.0 ok");
+        // An English sentence in a right-to-left paragraph keeps its full stop at its end.
+        assert_eq!(vis_lang("Hello world.", true, false), "Hello world.");
+        // Right-to-left runs keep W4: "45.6%" is one number.
+        assert_eq!(vis_lang("אב 45.6% גד", false, true), "דג 45.6% בא");
+        // Without right-to-left text or runs, the fast path.
+        let chars: Vec<char> = "plain, text".chars().collect();
+        assert_eq!(levels_lang("plain, text", &chars, false, &[false; 11]), vec![0; 11]);
+        assert!(is_rtl_lang("he-IL") && is_rtl_lang("ar") && is_rtl_lang("FA-ir") && !is_rtl_lang("en-US") && !is_rtl_lang(""));
+    }
+
     #[test]
     fn l1_resets_trailing_whitespace_and_tabs() {
         let chars: Vec<char> = "ab\tcd  ".chars().collect();

crates/text/src/tests.rs

@@ -101,11 +101,55 @@ fn pairs_are_kerned_only_from_the_kern_size() {
     assert!((above - off).abs() < 0.01, "40 pt is below a 48 pt threshold");
 }
 
+/// Width of the first paragraph "AVATAR WAVE" (kerned from 12 pt) when a second paragraph's run
+/// has character spacing `spc`.
+fn kerned_width_beside_spacing(family: &str, spc: f64) -> f64 {
+    let (p, mut sh) = setup("AVATAR WAVE", 2000.0, 300.0);
+    let t = sh.text.as_mut().unwrap();
+    let mut second = t.paragraphs[0].clone();
+    second.runs[0].props.spacing = Some(spc);
+    t.paragraphs.push(second);
+    for para in &mut t.paragraphs {
+        para.props.bullet = Some(Bullet::None);
+        for r in &mut para.runs {
+            r.props.font = Some(family.into());
+            r.props.size = Some(40.0);
+            r.props.kern = Some(12.0);
+        }
+    }
+    let l = lay(&p, &sh, 2000.0, 300.0);
+    l.lines[0].extent.1 - l.lines[0].extent.0
+}
+
+#[test]
+fn character_spacing_in_the_body_keeps_kerning() {
+    let kerns = |f: &FontFace| {
+        let w = |feat: &[deckcraft_fonts::Feature]| deckcraft_fonts::shape(f, "AVATAR", feat, |c| c).iter().map(|g| g.x_advance).sum::<i32>();
+        w(&[]) != w(&deckcraft_fonts::feature("-kern").into_iter().collect::<Vec<_>>())
+    };
+    let Some(family) = first_family(LATIN_FAMILIES, kerns) else {
+        eprintln!("skipped: no font that kerns AVATAR");
+        return;
+    };
+    let (_, off) = glyphs_and_width(&family, "AVATAR WAVE", Some(0.0));
+    let (_, on) = glyphs_and_width(&family, "AVATAR WAVE", Some(12.0));
+    assert!(on < off);
+    // Spacing elsewhere in the box leaves the pairs kerned (Calibri, Segoe UI, Times New Roman in
+    // PowerPoint; only Arial drops them).
+    for spc in [0.0, 0.5, -1.0, 0.6, 2.0] {
+        let w = kerned_width_beside_spacing(&family, spc);
+        assert!((w - on).abs() < 0.01, "{family} spc {spc}: {w} vs {on}");
+    }
+}
+
 #[test]
 fn ligatures_stay_for_scripts_that_need_them() {
     let has = |f: &[deckcraft_fonts::Feature], tag: &str| f.iter().any(|x| Some(*x) == deckcraft_fonts::feature(tag));
-    let cells =
-        |s: &str| s.chars().map(|ch| Cell { ch, style: 0, face: 0, level: 0, glyphs: vec![], adv: 0.0, head: 0, boundary: true }).collect::<Vec<_>>();
+    let cells = |s: &str| {
+        s.chars()
+            .map(|ch| Cell { ch, style: 0, face: 0, level: 0, glyphs: vec![], adv: 0.0, head: 0, boundary: true, upright: false })
+            .collect::<Vec<_>>()
+    };
     let latin = shaping_features(&cells("office"), &[], Some(*b"Latn"));
     assert!(has(&latin, "-liga") && has(&latin, "-clig") && has(&latin, "-kern"));
     // Arabic needs its ligatures; emoji sequences are joined by them.
@@ -264,7 +308,11 @@ fn arabic_face() -> Option<Arc<FontFace>> {
 
 #[test]
 fn rtl_mixed_string_is_reordered_per_line() {
-    let (p, sh) = bidi_setup(vec![Run::new(MIXED)], 2000.0, true, Align::Right);
+    // An Arabic run (PowerPoint tags typed Arabic `ar-…`): its digits and brackets go with the
+    // right-to-left text.
+    let mut run = Run::new(MIXED);
+    run.props.lang = Some("ar-SA".into());
+    let (p, sh) = bidi_setup(vec![run], 2000.0, true, Align::Right);
     let l = lay(&p, &sh, 2000.0, 300.0);
     assert_eq!(l.lines.len(), 1);
     let line = &l.lines[0];
@@ -293,6 +341,20 @@ fn rtl_mixed_string_is_reordered_per_line() {
     assert_eq!(line.levels[10], 2);
 }
 
+#[test]
+fn an_english_run_keeps_digits_and_brackets_left_to_right() {
+    // The same text in a run without a right-to-left language: PowerPoint keeps "2024 (Retrait) "
+    // one left-to-right stretch, its number on the left.
+    let (p, sh) = bidi_setup(vec![Run::new(MIXED)], 2000.0, true, Align::Right);
+    let l = lay(&p, &sh, 2000.0, 300.0);
+    let line = &l.lines[0];
+    let mid = |k: usize| (line.edges[k].0 + line.edges[k].1) / 2.0;
+    assert!(mid(0) > mid(10), "first Arabic word right of the Latin");
+    assert!(mid(4) < mid(10), "number left of the Latin word");
+    assert!(mid(9) < mid(10) && mid(17) > mid(16), "brackets around Retrait, unmirrored");
+    assert!(mid(19) < mid(4), "last Arabic word on the left");
+}
+
 #[test]
 fn rtl_paragraph_starts_at_the_right_with_the_bullet_outside() {
     let (p, mut sh) = bidi_setup(vec![Run::new("مرحبا بكم")], 400.0, true, Align::Right);
@@ -759,3 +821,398 @@ fn symbol_char_maps_symbol_font_codes() {
     assert_eq!(symbol_char(&face, "Wingdings", '\u{F06E}'), Some('\u{25A0}'));
     assert_eq!(symbol_char(&face, "Wingdings", '\u{100}'), None, "not a symbol code");
 }
+
+#[test]
+fn symbol_font_characters_draw_in_the_sym_font() {
+    // PowerPoint stores a Symbol-font character as U+F0xx with `<a:sym typeface="Symbol"/>`:
+    // U+F0DE is the Symbol font's double arrow (⇒). It must come from that font, not from
+    // whichever installed font happens to map U+F0DE (Wingdings draws an arrow at another angle).
+    let symbol = "Symbol";
+    if !FontDb::global().has_family(symbol) {
+        eprintln!("skipped: no Symbol font installed");
+        return;
+    }
+    let (p, mut sh) = setup("x\u{F0DE}y", 600.0, 300.0);
+    let para = &mut sh.text.as_mut().unwrap().paragraphs[0];
+    para.props.bullet = Some(Bullet::None);
+    para.runs[0].props.font = Some("Arial".into());
+    para.runs[0].props.font_sym = Some(symbol.into());
+    let l = lay(&p, &sh, 600.0, 300.0);
+    let families: Vec<(String, (usize, usize))> = l.runs.iter().map(|r| (r.face.family.clone(), r.chars)).collect();
+    assert!(families.iter().any(|(f, c)| f.eq_ignore_ascii_case(symbol) && c.0 == 1), "{families:?}");
+    // The letters around it keep the run's font.
+    assert!(families.iter().all(|(f, c)| c.0 == 1 || !f.eq_ignore_ascii_case(symbol)), "{families:?}");
+}
+
+#[test]
+fn small_capitals_draw_smaller_than_the_capitals_beside_them() {
+    let (p, mut sh) = setup("HxHx", 2000.0, 300.0);
+    let para = &mut sh.text.as_mut().unwrap().paragraphs[0];
+    para.props.bullet = Some(Bullet::None);
+    para.runs[0].props.caps = Some(Caps::Small);
+    para.runs[0].props.size = Some(40.0);
+    let l = lay(&p, &sh, 2000.0, 300.0);
+    let sizes: Vec<(usize, f64)> = l.runs.iter().map(|r| (r.glyphs.len(), r.size)).collect();
+    // H at 40 pt, x as a capital at 80 % (four runs: the size changes at every letter).
+    assert_eq!(sizes, vec![(1, 40.0), (1, 32.0), (1, 40.0), (1, 32.0)]);
+}
+
+#[test]
+fn capitals_keep_characters_whose_capital_is_a_sequence() {
+    assert_eq!(caps_char('a'), 'A');
+    assert_eq!(caps_char('dž'), 'DŽ');
+    // PowerPoint draws "ß", "fi" and "ʼn" unchanged in all caps.
+    assert_eq!(caps_char('ß'), 'ß');
+    assert_eq!(caps_char('\u{FB01}'), '\u{FB01}');
+    assert_eq!(caps_char('ʼn'), 'ʼn');
+    let (p, mut sh) = setup("aß", 2000.0, 300.0);
+    let para = &mut sh.text.as_mut().unwrap().paragraphs[0];
+    para.runs[0].props.caps = Some(Caps::All);
+    let l = lay(&p, &sh, 2000.0, 300.0);
+    let r = l.runs.iter().find(|r| !r.cells.is_empty()).unwrap();
+    let face = &r.face;
+    if face.covers('ß') {
+        assert_eq!(r.glyphs[1].0, face.glyph_for('ß'), "ß is not drawn as S");
+    }
+}
+
+#[test]
+fn transparent_text_is_faded_once() {
+    let (p, mut sh) = setup("Faded", 2000.0, 300.0);
+    let run = &mut sh.text.as_mut().unwrap().paragraphs[0].runs[0];
+    run.props.fill = Some(deckcraft_model::Fill::solid(
+        deckcraft_model::ColorRef::rgb(deckcraft_color::Rgba::rgb(255, 0, 0)).with(deckcraft_color::ColorTransform::Alpha(40000)),
+    ));
+    let l = lay(&p, &sh, 2000.0, 300.0);
+    let r = l.runs.iter().find(|r| !r.cells.is_empty()).unwrap();
+    // 60 % transparency: 40 % opaque in all, not 40 % of 40 %.
+    let opacity = r.color.a as f64 / 255.0 * r.alpha;
+    assert!((opacity - 0.4).abs() < 0.01, "{opacity}");
+}
+
+/// One paragraph `text` with tab stops `tabs` (position, `algn`), no bullet or indent.
+fn tabbed(text: &str, tabs: &[(f64, &str)], w: f64) -> TextLayout {
+    let (p, mut sh) = setup(text, w, 300.0);
+    let para = &mut sh.text.as_mut().unwrap().paragraphs[0];
+    for r in &mut para.runs {
+        r.props.size = Some(18.0);
+    }
+    let pp = &mut para.props;
+    pp.bullet = Some(Bullet::None);
+    pp.margin_left = Some(0.0);
+    pp.indent = Some(0.0);
+    pp.default_tab = Some(72.0);
+    pp.tabs = Some(tabs.iter().map(|(pos, a)| deckcraft_model::text::TabStop { pos: *pos, align: a.to_string() }).collect());
+    lay(&p, &sh, w, 300.0)
+}
+
+#[test]
+fn tab_stops_align_the_text_after_them() {
+    let x0 = |l: &TextLayout| l.inner.x0;
+    // Right: the text ends at the stop. Centre: centred on it. Decimal: the "." at the stop.
+    let l = tabbed("a\tright", &[(200.0, "r")], 600.0);
+    assert!((l.lines[0].extent.1 - x0(&l) - 200.0).abs() < 0.01, "{:?}", l.lines[0].extent);
+    let l = tabbed("a\tmid", &[(200.0, "ctr")], 600.0);
+    let (s, e) = (l.lines[0].edges[2].0, l.lines[0].edges[4].1);
+    assert!(((s + e) / 2.0 - x0(&l) - 200.0).abs() < 0.01);
+    let l = tabbed("x\t1234.567", &[(150.0, "dec")], 600.0);
+    assert!((l.lines[0].edges[6].0 - x0(&l) - 150.0).abs() < 0.01, "the point sits at the stop");
+    // Text without a point ends at a decimal stop.
+    let l = tabbed("x\t12,5", &[(150.0, "dec")], 600.0);
+    assert!((l.lines[0].extent.1 - x0(&l) - 150.0).abs() < 0.01);
+    // Text wider than the room before a right stop starts where the tab is; it never moves back.
+    let l = tabbed("x\twider than the gap", &[(20.0, "r")], 600.0);
+    assert!((l.lines[0].edges[2].0 - l.lines[0].edges[0].1).abs() < 0.01);
+    // A left stop and then default stops every 72 pt.
+    let l = tabbed("a\tb\tc", &[(30.0, "l")], 600.0);
+    assert!((l.lines[0].edges[2].0 - x0(&l) - 30.0).abs() < 0.01);
+    assert!((l.lines[0].edges[4].0 - x0(&l) - 72.0).abs() < 0.01);
+}
+
+#[test]
+fn a_tab_past_the_end_moves_to_the_next_line() {
+    // PowerPoint: "abcdefghij\tk\tl\tm…" in a narrow box puts the tab that doesn't fit on the next
+    // line, so the text after it lands on that line's first stop.
+    let l = tabbed("abcdefghij\tk", &[], 130.0);
+    assert_eq!(l.lines.len(), 2);
+    assert_eq!(l.lines[1].start, 10, "the tab starts the second line: {:?}", l.lines.iter().map(|x| (x.start, x.end, x.extent)).collect::<Vec<_>>());
+    assert!((l.lines[1].edges[1].0 - l.inner.x0 - 72.0).abs() < 0.01);
+}
+
+/// Underline decorations of "ab cd" underlined `u` at 40 pt.
+fn underline_decos(u: &str) -> (TextLayout, Vec<Deco>) {
+    let (p, mut sh) = setup("ab cd", 2000.0, 300.0);
+    let para = &mut sh.text.as_mut().unwrap().paragraphs[0];
+    para.props.bullet = Some(Bullet::None);
+    para.runs[0].props.size = Some(40.0);
+    para.runs[0].props.underline = Some(u.into());
+    let l = lay(&p, &sh, 2000.0, 300.0);
+    let d = l.decos.iter().filter(|d| !d.behind).cloned().collect();
+    (l, d)
+}
+
+#[test]
+fn underlines_sit_at_the_font_underline_in_their_style() {
+    let (l, sng) = underline_decos("sng");
+    let r = l.runs.iter().find(|r| !r.cells.is_empty()).unwrap();
+    let k = 40.0 / r.face.upem;
+    let base = l.lines[0].baseline;
+    assert_eq!(sng.len(), 1);
+    assert!((sng[0].rect.y0 - base - r.face.underline.0 * k).abs() < 0.01, "top at the font's underline position");
+    assert!((sng[0].rect.height() - (r.face.underline.1 * k).max(0.5)).abs() < 0.01);
+    let t = sng[0].rect.height();
+    // Double: two thin lines spanning from one thickness above the single line to its bottom.
+    let (_, dbl) = underline_decos("dbl");
+    assert_eq!(dbl.len(), 2);
+    assert!((dbl[0].rect.y0 - (sng[0].rect.y0 - t)).abs() < 0.01 && (dbl[1].rect.y1 - sng[0].rect.y1).abs() < 0.01);
+    // Heavy is thicker; dotted is dots as long as the line is thick.
+    let (_, heavy) = underline_decos("heavy");
+    assert!(heavy[0].rect.height() > t * 1.4);
+    let (_, dotted) = underline_decos("dotted");
+    assert_eq!(dotted[0].line, DecoLine::Dashed(Dash::Dot));
+    let pieces = dotted[0].pieces();
+    assert!(pieces.len() > 3);
+    assert!((pieces[0].width() - t).abs() < 0.01 && (pieces[1].x0 - pieces[0].x1 - t).abs() < 0.01);
+    // Wavy: a zigzag between the box's top and bottom.
+    let (_, wavy) = underline_decos("wavy");
+    let (pts, w) = wavy[0].wave().expect("a wave");
+    assert!(pts.len() > 4 && w > 0.0 && w < t);
+    assert!(pts[0].y < pts[1].y);
+    // "words" underlines the spaces too, as PowerPoint draws it: one line.
+    let (_, words) = underline_decos("words");
+    assert_eq!(words.len(), 1);
+}
+
+#[test]
+fn no_break_after_a_zero_width_space_or_before_an_em_dash() {
+    let (allowed, _) = break_opportunities("ab\u{200B}cd", false);
+    assert!(!allowed[3], "PowerPoint does not break after a zero-width space");
+    let (allowed, _) = break_opportunities("ab\u{2014}cd", false);
+    assert!(!allowed[2] && allowed[3], "an em dash ends a line, never starts one");
+}
+
+#[test]
+fn a_line_broken_at_a_soft_hyphen_shows_a_hyphen() {
+    let (p, mut sh) = setup("Soft\u{AD}hyphenated\u{AD}words", 150.0, 300.0);
+    let para = &mut sh.text.as_mut().unwrap().paragraphs[0];
+    para.props.bullet = Some(Bullet::None);
+    para.runs[0].props.size = Some(24.0);
+    let l = lay(&p, &sh, 150.0, 300.0);
+    assert!(l.lines.len() >= 2);
+    let first = &l.lines[0];
+    let shy = first.end - 1;
+    assert_eq!(first.end, 5, "breaks after the soft hyphen: {:?}", l.lines.iter().map(|x| (x.start, x.end)).collect::<Vec<_>>());
+    let (x0, x1) = first.edges[shy - first.start];
+    assert!(x1 - x0 > 2.0, "the hyphen takes room");
+    let r = l.runs.iter().find(|r| r.cells.iter().any(|c| c.0 == shy)).expect("a glyph for the soft hyphen");
+    assert_eq!(r.glyphs[r.cells.iter().position(|c| c.0 == shy).unwrap()].0, r.face.glyph_for('-'));
+    // Soft hyphens draw only where a line ends; in a wide box, nowhere.
+    let ends: Vec<usize> = l.lines.iter().map(|x| x.end.saturating_sub(1)).collect();
+    for r in &l.runs {
+        for (g, c) in r.glyphs.iter().zip(&r.cells) {
+            assert!(c.1 != '\u{AD}' || ends.contains(&c.0) || g.0 != r.face.glyph_for('-'), "mid-line soft hyphen drawn");
+        }
+    }
+    let wide = lay(&p, &sh, 2000.0, 300.0);
+    assert_eq!(wide.lines.len(), 1);
+    assert!(wide.runs.iter().all(|r| r.cells.iter().all(|c| c.1 != '\u{AD}' || r.glyphs.iter().all(|g| g.0 != r.face.glyph_for('-')))));
+}
+
+#[test]
+fn small_kana_and_closing_brackets_follow_powerpoint_kinsoku() {
+    // "っ" and "ー" never start a line: the character before them moves down too.
+    let w = one_line("あいうえお") + 0.5;
+    for (text, first) in [("あいうえおっかき", "あいうえ"), ("あいうえおーかき", "あいうえ"), ("あいうえおかき", "あいうえお")]
+    {
+        let lines = wrapped(text, w, |p| p.hanging_punct = Some(true));
+        assert_eq!(lines[0], first, "{text}: {lines:?}");
+    }
+    // A closing bracket doesn't hang like "。" does: "「。」" overflowing by "」" moves down whole.
+    let w = one_line("あいうえ「。") + 0.5;
+    let lines = wrapped("あいうえ「。」かき", w, |p| p.hanging_punct = Some(true));
+    assert_eq!(lines[0], "あいうえ", "{lines:?}");
+}
+
+#[test]
+fn autonumber_schemes_follow_powerpoint() {
+    // As PowerPoint's export draws them (start values as in the probe deck).
+    for (scheme, n, want) in [
+        ("ea1ChsPlain", 4, "四"),
+        ("ea1ChsPeriod", 10, "十．"),
+        ("ea1ChtPeriod", 21, "二十一．"),
+        ("ea1JpnKorPeriod", 10, "一〇．"),
+        ("ea1JpnChsDbPeriod", 13, "一三．"),
+        ("arabicDbPlain", 10, "１０"),
+        ("arabicDbPeriod", 13, "１３．"),
+        ("circleNumDbPlain", 13, "⑬"),
+        ("circleNumWdWhitePlain", 13, "③"),
+        ("circleNumWdBlackPlain", 2, "❷"),
+        ("thaiAlphaPeriod", 1, "ก."),
+        ("thaiAlphaParenR", 4, "ง)"),
+        ("thaiAlphaParenBoth", 7, "(ช)"),
+        ("thaiNumPeriod", 10, "๑๐."),
+        ("hindiAlphaPeriod", 4, "ई."),
+        ("hindiAlpha1Period", 1, "क."),
+        ("hindiNumParenR", 13, "१३)"),
+        ("hebrew2Minus", 1, "א-"),
+        ("arabic1Minus", 13, "ش-"),
+        ("arabic2Minus", 10, "ي-"),
+        ("arabicPlain", 10, "10"),
+    ] {
+        assert_eq!(autonum(scheme, n), want, "{scheme} {n}");
+    }
+    assert_eq!(chinese_num(105), "一百零五");
+    assert_eq!(chinese_num(20), "二十");
+    // Past the end of an alphabet the letter doubles, like "aa".
+    assert_eq!(autonum("hebrew2Minus", 23), "אא-");
+    assert_eq!(autonum("thaiAlphaPeriod", 0), ".");
+}
+
+#[test]
+fn east_asian_vertical_text_marks_cjk_upright() {
+    let (p, mut sh) = setup("日本、ABC 12", 300.0, 600.0);
+    sh.text.as_mut().unwrap().body.vert = Some(deckcraft_model::text::TextDir::EaVertical);
+    let l = lay(&p, &sh, 300.0, 600.0);
+    assert_eq!(l.rotation, 90.0);
+    let upright: Vec<bool> = l
+        .runs
+        .iter()
+        .filter(|r| !r.cells.is_empty())
+        .flat_map(|r| r.cells.iter().map(move |c| (c.1, r.upright)))
+        .filter(|(c, _)| *c != ' ')
+        .map(|(_, u)| u)
+        .collect();
+    assert_eq!(upright, vec![true, true, true, false, false, false, false, false]);
+    // In vert nothing stands upright.
+    sh.text.as_mut().unwrap().body.vert = Some(deckcraft_model::text::TextDir::Vertical);
+    let l = lay(&p, &sh, 300.0, 600.0);
+    assert!(l.runs.iter().all(|r| !r.upright));
+    assert!(is_upright('あ') && is_upright('、') && is_upright('Ａ') && !is_upright('A') && !is_upright('1'));
+}
+
+#[test]
+fn mongolian_lines_run_left_to_right_and_stacked_letters_stand_one_em_apart() {
+    let (p, mut sh) = setup("one\ntwo", 200.0, 400.0);
+    sh.text.as_mut().unwrap().body.vert = Some(deckcraft_model::text::TextDir::Vertical);
+    let v = lay(&p, &sh, 200.0, 400.0);
+    sh.text.as_mut().unwrap().body.vert = Some(deckcraft_model::text::TextDir::MongolianVertical);
+    let m = lay(&p, &sh, 200.0, 400.0);
+    assert_eq!(m.rotation, 90.0);
+    // In layout space (turned a quarter turn) vert puts the first line at the top, which shows on
+    // the right; mongolianVert mirrors the line places, so the first line shows on the left.
+    assert!(v.lines[0].top < v.lines[1].top);
+    assert!(m.lines[0].top > m.lines[1].top);
+    let mid = (m.inner.y0 + m.inner.y1) / 2.0;
+    assert!(((m.lines[0].top + m.lines[0].bottom) / 2.0 - mid + ((v.lines[0].top + v.lines[0].bottom) / 2.0 - mid)).abs() < 0.01);
+    // Stacked: every letter upright, one em apart.
+    let (p, mut sh) = setup("Lil", 200.0, 400.0);
+    let t = sh.text.as_mut().unwrap();
+    t.body.vert = Some(deckcraft_model::text::TextDir::Stacked);
+    t.paragraphs[0].runs[0].props.size = Some(20.0);
+    let s = lay(&p, &sh, 200.0, 400.0);
+    assert!(s.runs.iter().filter(|r| !r.cells.is_empty()).all(|r| r.upright));
+    // Its lines run left to right too.
+    let (p2, mut sh2) = setup("one\ntwo", 200.0, 400.0);
+    sh2.text.as_mut().unwrap().body.vert = Some(deckcraft_model::text::TextDir::Stacked);
+    let st = lay(&p2, &sh2, 200.0, 400.0);
+    assert!(st.lines[0].top > st.lines[1].top);
+    // wordArtVertRtl stacks the same way with lines from right to left.
+    sh2.text.as_mut().unwrap().body.vert = Some(deckcraft_model::text::TextDir::StackedRtl);
+    let sr = lay(&p2, &sh2, 200.0, 400.0);
+    assert!(sr.lines[0].top < sr.lines[1].top);
+    assert!(sr.runs.iter().filter(|r| !r.cells.is_empty()).all(|r| r.upright));
+    let e = &s.lines[0].edges;
+    assert!((e[1].1 - e[1].0 - 20.0).abs() < 0.01 && (e[2].1 - e[2].0 - 20.0).abs() < 0.01, "{e:?}");
+}
+
+#[test]
+fn symbols_after_an_emoji_keep_a_text_face() {
+    // "✅ ⚠ ™": PowerPoint draws ✅ (emoji presentation) in colour and the symbols after it as text.
+    let db = FontDb::global();
+    if !db.cascade(&['✅'], &[], "Regular").is_color() {
+        return;
+    }
+    let (p, sh) = bidi_setup(vec![Run::new("✅ ⚠ ™")], 2000.0, false, Align::Left);
+    let l = lay(&p, &sh, 2000.0, 300.0);
+    for r in &l.runs {
+        for (_, c) in &r.cells {
+            assert_eq!(r.face.is_color(), *c == '✅', "{c:?} drawn with {}", r.face.family);
+        }
+    }
+}
+
+#[test]
+fn fallback_faces_do_not_move_the_baseline() {
+    // PowerPoint keeps a line's baseline and pitch from the run's own font when an emoji, a symbol
+    // or a script the font lacks is drawn from another face.
+    let base = |text: &str| {
+        let (p, sh) = bidi_setup(vec![Run::new(text)], 2000.0, false, Align::Left);
+        let l = lay(&p, &sh, 2000.0, 300.0);
+        (l.lines[0].baseline, l.lines[0].bottom)
+    };
+    let plain = base("Hxg Hxg");
+    for text in ["Hxg \u{1F600} Hxg", "Hxg \u{0E2A}\u{0E27}\u{0E31}\u{0E2A}", "Hxg \u{222B}\u{2211}"] {
+        let b = base(text);
+        assert!((b.0 - plain.0).abs() < 0.01 && (b.1 - plain.1).abs() < 0.01, "{text:?}: {b:?} vs {plain:?}");
+    }
+}
+
+#[test]
+fn strikethrough_sits_at_the_font_strikeout_position() {
+    let (p, mut sh) = setup("Struck", 2000.0, 300.0);
+    let para = &mut sh.text.as_mut().unwrap().paragraphs[0];
+    para.props.bullet = Some(Bullet::None);
+    para.runs[0].props.size = Some(96.0);
+    para.runs[0].props.strike = Some(Strike::Single);
+    let l = lay(&p, &sh, 2000.0, 300.0);
+    let r = l.runs.iter().find(|r| !r.cells.is_empty()).unwrap();
+    let k = 96.0 / r.face.upem;
+    let d = l.decos.iter().find(|d| !d.behind).expect("a strikethrough");
+    assert!((l.lines[0].baseline - d.rect.y0 - r.face.strikeout.0 * k).abs() < 0.01, "top at the strikeout position");
+    assert!((d.rect.height() - (r.face.strikeout.1 * k).max(0.5)).abs() < 0.01);
+}
+
+#[test]
+fn rtl_columns_start_on_the_right_and_just_anchoring_sits_at_the_bottom() {
+    let text = "word ".repeat(200);
+    let (p, mut sh) = setup(&text, 400.0, 200.0);
+    let t = sh.text.as_mut().unwrap();
+    t.body.columns = Some(2);
+    t.body.col_spacing = Some(20.0);
+    t.paragraphs[0].runs[0].props.size = Some(12.0);
+    let ltr = lay(&p, &sh, 400.0, 200.0);
+    sh.text.as_mut().unwrap().body.rtl_col = Some(true);
+    let rtl = lay(&p, &sh, 400.0, 200.0);
+    let first = |l: &TextLayout| l.lines.iter().find(|x| x.column == 0).map(|x| x.extent.0).unwrap();
+    let second = |l: &TextLayout| l.lines.iter().find(|x| x.column == 1).map(|x| x.extent.0).unwrap();
+    assert!(first(&ltr) < second(&ltr));
+    assert!(first(&rtl) > second(&rtl), "with rtlCol the first column is on the right");
+    // anchor="just" and "dist" draw like "b".
+    let (p, mut sh) = setup("one line", 400.0, 300.0);
+    sh.text.as_mut().unwrap().body.anchor = Some(Anchor::Bottom);
+    let b = lay(&p, &sh, 400.0, 300.0).lines[0].top;
+    for a in [Anchor::Justified, Anchor::Distributed] {
+        sh.text.as_mut().unwrap().body.anchor = Some(a);
+        assert!((lay(&p, &sh, 400.0, 300.0).lines[0].top - b).abs() < 0.01, "{a:?}");
+    }
+}
+
+#[test]
+fn stacked_combining_marks_take_a_face_that_draws_them() {
+    // A letter with marks the run's font lacks draws in a face that has them all (no boxes).
+    let db = FontDb::global();
+    let cluster = ['Z', '\u{0334}', '\u{0321}', '\u{031B}'];
+    let run_face = db.face("Inter", "Regular");
+    let f = db.cascade(&cluster, std::slice::from_ref(&run_face), "Regular");
+    if !deckcraft_fonts::covers_cluster(&run_face, &cluster) && ["DejaVu Sans", "Segoe UI"].iter().any(|fam| db.has_family(fam)) {
+        // Make sure a face with the marks is loaded, then the cluster must take one.
+        for fam in ["DejaVu Sans", "Segoe UI"] {
+            if db.has_family(fam) {
+                let _ = db.face(fam, "Regular");
+            }
+        }
+        let f = db.cascade(&cluster, std::slice::from_ref(&run_face), "Regular");
+        assert!(deckcraft_fonts::covers_cluster(&f, &cluster), "{} lacks the marks", f.family);
+    }
+    let _ = f;
+}

crates/ui-egui/src/backstage_tests.rs

@@ -0,0 +1,438 @@
+//! The File tab (Backstage, #76) through real egui input: the File tab, Alt+F and Esc, every page,
+//! and the commands its pages run.
+#![allow(clippy::unwrap_used, clippy::expect_used)]
+
+use std::cell::RefCell;
+use std::rc::Rc;
+
+use deckcraft_engine::Session;
+use egui::accesskit::Role;
+use egui::{Key, Modifiers};
+use egui_kittest::Harness;
+use egui_kittest::kittest::Queryable;
+use serde_json::json;
+
+use super::*;
+use crate::{Services, SlideApp};
+
+fn harness(app: SlideApp) -> Harness<'static, SlideApp> {
+    let mut h = Harness::builder().with_size(egui::vec2(1400.0, 900.0)).build_ui_state(
+        |ui, app: &mut SlideApp| {
+            app.logic(ui.ctx());
+            app.ui(ui);
+        },
+        app,
+    );
+    // The app keeps asking for frames, so step instead of run().
+    h.run_steps(3);
+    h
+}
+
+fn new_app() -> SlideApp {
+    SlideApp::new(Session::with_new(), Services::default())
+}
+
+/// A folder of its own for one test's files.
+fn temp_dir(name: &str) -> std::path::PathBuf {
+    let d = std::env::temp_dir().join(format!("deckcraft-backstage-{}-{name}", std::process::id()));
+    let _ = std::fs::remove_dir_all(&d);
+    std::fs::create_dir_all(&d).unwrap();
+    d
+}
+
+/// Desktop services whose Save dialog answers with `dir`/<suggested name> and records the names.
+fn saving_into(dir: &std::path::Path) -> (Services, Rc<RefCell<Vec<String>>>) {
+    let asked: Rc<RefCell<Vec<String>>> = Default::default();
+    let log = asked.clone();
+    let dir = dir.to_path_buf();
+    let services = Services {
+        pick_save: Some(Box::new(move |suggested: &str| {
+            log.borrow_mut().push(suggested.to_string());
+            Some(dir.join(suggested).to_string_lossy().to_string())
+        })),
+        ..Default::default()
+    };
+    (services, asked)
+}
+
+/// Is `r` in the side menu (the harness insets the window by its default margin)?
+fn in_nav(r: egui::Rect) -> bool {
+    r.left() < 20.0 && r.right() <= NAV_W + 20.0
+}
+
+/// Clicks the button called `label` on the page (not the side menu's entry of the same name).
+fn click_on_page(h: &Harness<'_, SlideApp>, label: &str) {
+    let node = h
+        .query_all_by_role_and_label(Role::Button, label)
+        .find(|n| !in_nav(n.rect()))
+        .or_else(|| h.query_all_by_label(label).find(|n| !in_nav(n.rect())));
+    node.unwrap_or_else(|| panic!("no “{label}” button on the page")).click();
+}
+
+/// Clicks the side menu's entry called `label`.
+fn click_nav(h: &Harness<'_, SlideApp>, label: &str) {
+    let node = h.query_all_by_label(label).find(|n| in_nav(n.rect()));
+    node.unwrap_or_else(|| panic!("no “{label}” in the side menu")).click();
+}
+
+fn page(h: &Harness<'_, SlideApp>) -> Option<Page> {
+    h.state().backstage.as_ref().map(|b| b.page)
+}
+
+#[test]
+fn page_ids_round_trip_and_unknown_ids_are_refused() {
+    for p in Page::ALL {
+        assert_eq!(Page::parse(p.id()), Some(p));
+    }
+    assert_eq!(Page::parse(" SAVEAS "), Some(Page::SaveAs));
+    assert_eq!(Page::parse("share"), None);
+    assert_eq!(Page::parse(""), None);
+    let (top, bottom) = entries(false);
+    assert_eq!(top, vec![Nav::Page(Page::Home), Nav::Page(Page::New), Nav::Page(Page::Open)], "the start screen has no presentation pages");
+    assert_eq!(bottom, vec![Nav::Page(Page::Account), Nav::Options]);
+    assert_eq!(entries(true).0.len(), 9);
+    assert_eq!(split_path("/home/me/Talk.pptx"), ("Talk.pptx".into(), "/home/me".into()));
+    assert_eq!(format_bytes(512), "512 bytes");
+    assert_eq!(format_bytes(33_485), "32.7 KB");
+}
+
+/// The File tab opens Home in place of the ribbon; Esc and the back arrow return.
+#[test]
+fn the_file_tab_opens_the_backstage_and_esc_or_back_returns() {
+    let mut h = harness(new_app());
+    assert!(h.query_by_label("Blank Presentation").is_none(), "the slide shows first");
+    h.get_by_label("File").click();
+    h.run_steps(3);
+    assert_eq!(page(&h), Some(Page::Home));
+    assert!(h.state().backstage_open());
+    assert!(h.query_by_label("Blank Presentation").is_some(), "Home offers new presentations");
+    assert!(h.query_by_label("File").is_none(), "the ribbon is hidden");
+    h.key_press(Key::Escape);
+    h.run_steps(3);
+    assert!(!h.state().backstage_open(), "Esc goes back to the slide");
+    assert!(h.query_by_label("File").is_some());
+
+    h.get_by_label("File").click();
+    h.run_steps(3);
+    h.get_by_label("Back").click();
+    h.run_steps(3);
+    assert!(!h.state().backstage_open(), "so does the back arrow");
+    assert_eq!(h.state().session.documents().len(), 1, "nothing was created or closed");
+}
+
+/// Alt+F opens it with the keyboard in the side menu; arrows walk it (pages show as they get the
+/// focus); Enter runs an action; Esc goes back.
+#[test]
+fn alt_f_arrows_enter_and_esc_drive_the_side_menu() {
+    let mut h = harness(new_app());
+    h.key_press_modifiers(Modifiers::ALT, Key::F);
+    h.run_steps(3);
+    assert_eq!(page(&h), Some(Page::Home));
+    assert_eq!(h.state().backstage.as_ref().and_then(|b| b.focus), Some(0));
+    for want in [Page::New, Page::Open, Page::Info] {
+        h.key_press(Key::ArrowDown);
+        h.run_steps(2);
+        assert_eq!(page(&h), Some(want));
+    }
+    // Save has the focus now; the page stays Info until it is run.
+    h.key_press(Key::ArrowDown);
+    h.run_steps(2);
+    assert_eq!(page(&h), Some(Page::Info));
+    // A presentation that was never saved goes to Save As, as in PowerPoint.
+    h.key_press(Key::Enter);
+    h.run_steps(2);
+    assert_eq!(page(&h), Some(Page::SaveAs));
+    // Up from the top wraps to Options at the bottom.
+    for _ in 0..20 {
+        h.key_press(Key::ArrowUp);
+    }
+    h.run_steps(2);
+    h.key_press(Key::Escape);
+    h.run_steps(3);
+    assert!(!h.state().backstage_open());
+    assert!(!h.state().session.active().unwrap().is_dirty(), "the keys never reached the slide");
+}
+
+/// Every page draws its own content.
+#[test]
+fn every_page_renders() {
+    let mut h = harness(new_app());
+    let last_theme = deckcraft_model::theme::builtin_themes().last().map(|t| t.name.clone()).unwrap();
+    let checks: [(Page, &str); 8] = [
+        (Page::Home, "Recent"),
+        (Page::New, &last_theme),
+        (Page::Open, "Browse"),
+        (Page::Info, "Hidden slides"),
+        (Page::SaveAs, "Not saved yet"),
+        (Page::Print, "Print Hidden Slides"),
+        (Page::Export, "Create PDF Document"),
+        (Page::Account, "About DeckCraft"),
+    ];
+    for (p, marker) in checks {
+        h.state_mut().run("app.backstage", json!({"page": p.id()})).unwrap();
+        h.run_steps(3);
+        assert_eq!(page(&h), Some(p));
+        assert!(h.query_all_by_label_contains(marker).next().is_some(), "{} shows “{marker}”", p.label());
+        let selected = h.query_all_by_label(p.label()).any(|n| in_nav(n.rect()));
+        assert!(selected, "{} is in the side menu", p.label());
+    }
+    assert!(h.state_mut().run("app.backstage", json!({"page": "share"})).is_err(), "Share (cloud) isn't offered");
+}
+
+/// New and Home create presentations, which leaves the File tab.
+#[test]
+fn new_creates_a_presentation() {
+    let mut h = harness(new_app());
+    h.state_mut().run("app.backstage", json!({"page": "new"})).unwrap();
+    h.run_steps(3);
+    h.get_by_label("Blank Presentation").click();
+    h.run_steps(3);
+    assert_eq!(h.state().session.documents().len(), 2);
+    assert!(h.state().backstage.is_none(), "the new presentation shows");
+
+    let theme = deckcraft_model::theme::builtin_themes().into_iter().nth(1).unwrap();
+    h.state_mut().run("app.backstage", json!({})).unwrap();
+    h.run_steps(3);
+    h.get_by_label(&theme.name).click();
+    h.run_steps(3);
+    assert_eq!(h.state().session.documents().len(), 3);
+    assert_eq!(h.state().session.active().unwrap().doc.masters[0].theme.name, theme.name);
+    assert!(h.state().backstage.is_none());
+}
+
+/// Open lists recent presentations by name (filtered by the search box) and opens one.
+#[test]
+fn open_lists_recent_files_and_opens_one() {
+    let dir = temp_dir("open");
+    let path = dir.join("Quarterly review.pptx").to_string_lossy().to_string();
+    let mut s = Session::with_new();
+    s.execute("file.saveAs", &json!({"path": path})).unwrap();
+    let mut app = SlideApp::new(Session::with_new(), Services::default());
+    app.ui.recent = vec![path.clone(), dir.join("Other.pptx").to_string_lossy().to_string()];
+    let mut h = harness(app);
+    h.state_mut().run("app.backstage", json!({"page": "open"})).unwrap();
+    h.run_steps(3);
+    assert!(h.query_by_label("Other.pptx").is_some());
+    h.state_mut().backstage.as_mut().unwrap().query = "quarter".into();
+    h.run_steps(2);
+    assert!(h.query_by_label("Other.pptx").is_none(), "the search box filters by name");
+    h.get_by_label("Quarterly review.pptx").click();
+    h.run_steps(3);
+    assert_eq!(h.state().session.documents().len(), 2);
+    assert_eq!(h.state().session.active().unwrap().path.as_deref(), Some(path.as_str()));
+    assert!(h.state().backstage.is_none(), "the opened presentation shows");
+    assert_eq!(h.state().ui.recent.first(), Some(&path));
+    let _ = std::fs::remove_dir_all(&dir);
+}
+
+/// Save As saves through the Save dialog and the presentation takes the new file; Export writes
+/// copies (PDF, another file type) and leaves the presentation's own file alone.
+#[test]
+fn save_as_and_export_run_the_file_commands() {
+    let dir = temp_dir("saveas");
+    let (services, asked) = saving_into(&dir);
+    let mut h = harness(SlideApp::new(Session::with_new(), services));
+    let title = h.state().session.active().unwrap().title();
+
+    // Save on a presentation without a file goes to Save As.
+    h.state_mut().run("app.backstage", json!({})).unwrap();
+    h.run_steps(3);
+    click_nav(&h, "Save");
+    h.run_steps(3);
+    assert_eq!(page(&h), Some(Page::SaveAs));
+    click_on_page(&h, "Save");
+    h.run_steps(3);
+    let pptx = dir.join(format!("{title}.pptx")).to_string_lossy().to_string();
+    assert!(std::path::Path::new(&pptx).is_file(), "saved as PowerPoint by default");
+    assert_eq!(h.state().session.active().unwrap().path.as_deref(), Some(pptx.as_str()));
+    assert!(h.state().backstage.is_none(), "a save returns to the slide");
+
+    // Export › Create PDF Document.
+    h.state_mut().run("app.backstage", json!({"page": "export"})).unwrap();
+    h.run_steps(3);
+    click_on_page(&h, "Create PDF");
+    h.run_steps(3);
+    let pdf = std::fs::read(dir.join(format!("{title}.pdf"))).unwrap();
+    assert!(pdf.starts_with(b"%PDF"));
+
+    // Export › Change File Type › Outline.
+    click_on_page(&h, "Change File Type");
+    h.run_steps(3);
+    click_on_page(&h, "Outline (*.txt)");
+    h.run_steps(2);
+    click_on_page(&h, "Save As");
+    h.run_steps(3);
+    assert!(dir.join(format!("{title}.txt")).is_file());
+    assert_eq!(h.state().session.active().unwrap().path.as_deref(), Some(pptx.as_str()), "exports are copies");
+    assert_eq!(*asked.borrow(), vec![format!("{title}.pptx"), format!("{title}.pdf"), format!("{title}.txt")]);
+
+    // Save with a file saves in place and goes back.
+    h.state_mut().run("slide.new", json!({})).unwrap();
+    h.state_mut().run("app.backstage", json!({})).unwrap();
+    h.run_steps(3);
+    click_nav(&h, "Save");
+    h.run_steps(3);
+    assert!(!h.state().session.active().unwrap().is_dirty());
+    assert!(h.state().backstage.is_none());
+    assert_eq!(asked.borrow().len(), 3, "no Save dialog for a presentation with a file");
+    let _ = std::fs::remove_dir_all(&dir);
+}
+
+/// Close closes a saved presentation at once and asks about unsaved changes first.
+#[test]
+fn close_closes_and_asks_about_unsaved_changes() {
+    let mut h = harness(new_app());
+    h.state_mut().run("app.backstage", json!({})).unwrap();
+    h.run_steps(3);
+    click_nav(&h, "Close");
+    h.run_steps(3);
+    assert_eq!(h.state().session.documents().len(), 0);
+    assert_eq!(page(&h), Some(Page::Home), "the start screen shows");
+    assert!(h.query_by_label("Back").is_none() && h.query_by_label("Close").is_none(), "nothing to go back to or close");
+
+    // Unsaved: Cancel keeps it, Don't Save closes it.
+    h.get_by_label("Blank Presentation").click();
+    h.run_steps(3);
+    h.state_mut().run("slide.new", json!({})).unwrap();
+    h.state_mut().run("app.backstage", json!({})).unwrap();
+    h.run_steps(3);
+    click_nav(&h, "Close");
+    h.run_steps(3);
+    assert_eq!(h.state().dialog.as_ref().map(|d| d.id.as_str()), Some("close"));
+    h.get_by_label("Cancel").click();
+    h.run_steps(3);
+    assert_eq!(h.state().session.documents().len(), 1);
+    assert!(h.state().backstage_open(), "Cancel leaves the File tab as it was");
+    click_nav(&h, "Close");
+    h.run_steps(3);
+    h.get_by_label("Don't Save").click();
+    h.run_steps(3);
+    assert_eq!(h.state().session.documents().len(), 0);
+}
+
+/// Ctrl+W asks too (it used to close unsaved presentations without a word).
+#[test]
+fn ctrl_w_asks_before_closing_unsaved_changes() {
+    let mut h = harness(new_app());
+    h.state_mut().run("slide.new", json!({})).unwrap();
+    h.run_steps(2);
+    h.key_press_modifiers(Modifiers::COMMAND, Key::W);
+    h.run_steps(3);
+    assert_eq!(h.state().session.documents().len(), 1);
+    assert_eq!(h.state().dialog.as_ref().map(|d| d.id.as_str()), Some("close"));
+}
+
+/// Info shows the presentation's counts and properties, and edits them through file.properties.
+#[test]
+fn info_shows_and_edits_the_properties() {
+    let mut app = new_app();
+    app.run("file.properties", json!({"title": "Quarterly", "keywords": "sales"})).unwrap();
+    app.run("slide.new", json!({})).unwrap();
+    app.run("slide.hide", json!({})).unwrap();
+    let mut h = harness(app);
+    h.state_mut().run("app.backstage", json!({"page": "info"})).unwrap();
+    h.run_steps(3);
+    assert_eq!(h.get_by_role_and_label(Role::TextInput, "Title").value().as_deref(), Some("Quarterly"));
+    assert_eq!(h.get_by_role_and_label(Role::TextInput, "Tags").value().as_deref(), Some("sales"));
+    assert!(h.query_all_by_label("Not saved yet").next().is_some());
+    let author = h.get_by_role_and_label(Role::TextInput, "Author");
+    author.click();
+    h.run_steps(2);
+    h.get_by_role_and_label(Role::TextInput, "Author").type_text("Ada");
+    h.run_steps(2);
+    h.key_press(Key::Enter);
+    h.run_steps(3);
+    assert_eq!(h.state().session.active().unwrap().doc.props.author, "Ada");
+    // Esc in a field leaves the field; the next one goes back.
+    assert!(h.state().backstage_open());
+}
+
+/// With nothing open the File tab is the start screen: Home, New and Open, no back arrow, and Esc
+/// has nowhere to go.
+#[test]
+fn the_start_screen_is_file_home() {
+    let mut h = harness(SlideApp::new(Session::new(), Services::default()));
+    assert_eq!(page(&h), Some(Page::Home));
+    assert!(h.query_by_label("Back").is_none());
+    assert!(h.query_all_by_label("Info").next().is_none());
+    h.key_press(Key::Escape);
+    h.run_steps(2);
+    assert_eq!(page(&h), Some(Page::Home));
+    h.key_press(Key::ArrowDown);
+    h.run_steps(2);
+    assert_eq!(page(&h), Some(Page::New));
+    assert!(h.state_mut().run("app.backstage", json!({"page": "print"})).is_err(), "nothing to print");
+    h.get_by_label("Blank Presentation").click();
+    h.run_steps(3);
+    assert_eq!(h.state().session.documents().len(), 1);
+    assert!(h.state().backstage.is_none());
+}
+
+/// Print previews the pages its settings make and prints through a PDF opened in the system
+/// viewer.
+#[test]
+fn print_previews_pages_and_prints_a_pdf() {
+    let dir = temp_dir("print");
+    let (services, _) = saving_into(&dir);
+    let mut app = SlideApp::new(Session::with_new(), services);
+    for _ in 0..3 {
+        app.run("slide.new", json!({})).unwrap();
+    }
+    app.run("slide.hide", json!({"index": 1})).unwrap();
+    let mut h = harness(app);
+    h.key_press_modifiers(Modifiers::COMMAND, Key::P);
+    h.run_steps(3);
+    assert_eq!(page(&h), Some(Page::Print), "Ctrl+P opens File › Print");
+    assert!(h.query_by_label("1 of 3").is_some(), "hidden slides are left out");
+    h.state_mut().backstage.as_mut().unwrap().print_layout = "h4";
+    h.run_steps(2);
+    assert!(h.query_by_label("1 of 1").is_some(), "four slides a page");
+    h.state_mut().backstage.as_mut().unwrap().print_layout = "slides";
+    h.state_mut().backstage.as_mut().unwrap().print_hidden = true;
+    h.run_steps(2);
+    assert!(h.query_by_label("1 of 4").is_some());
+    h.get_by_label("Next Page").click();
+    h.run_steps(2);
+    assert!(h.query_by_label("2 of 4").is_some());
+    {
+        let bs = h.state_mut().backstage.as_mut().unwrap();
+        bs.print_scope = PrintScope::Custom;
+        bs.print_range = "9".into();
+    }
+    h.run_steps(2);
+    assert!(h.query_by_label_contains("outside them").is_some(), "a bad range says why");
+    h.state_mut().backstage.as_mut().unwrap().print_range = "1-2".into();
+    h.run_steps(2);
+    click_on_page(&h, "Print");
+    h.run_steps(2);
+    let url = h.state().pending_urls.first().cloned().unwrap_or_default();
+    // The URL was handed to egui at the end of the frame; check what it pointed at.
+    let printed = std::env::temp_dir().join(format!("{} (print).pdf", h.state().session.active().unwrap().title()));
+    assert!(printed.is_file(), "the PDF to print was written: {url}");
+    assert!(std::fs::read(&printed).unwrap().starts_with(b"%PDF"));
+    let _ = std::fs::remove_file(printed);
+    let _ = std::fs::remove_dir_all(&dir);
+}
+
+#[test]
+fn print_slides_follow_the_settings() {
+    let mut s = Session::with_new();
+    for _ in 0..4 {
+        s.execute("slide.new", &json!({})).unwrap();
+    }
+    s.execute("slide.hide", &json!({"index": 2})).unwrap();
+    let doc = s.doc().unwrap().doc.clone();
+    let mut bs = Backstage::new(Page::Print, (1, Some(0)));
+    assert_eq!(print_slides(&doc, &bs, 0).unwrap(), vec![0, 1, 3, 4]);
+    bs.print_hidden = true;
+    assert_eq!(print_slides(&doc, &bs, 0).unwrap().len(), 5);
+    bs.print_scope = PrintScope::Current;
+    assert_eq!(print_slides(&doc, &bs, 2).unwrap(), vec![2], "the current slide prints even when hidden");
+    bs.print_scope = PrintScope::Custom;
+    bs.print_range = "2-4".into();
+    bs.print_hidden = false;
+    assert_eq!(print_slides(&doc, &bs, 0).unwrap(), vec![1, 3]);
+    bs.print_layout = "h6";
+    assert_eq!(print_params(&bs, &[1, 3])["perPage"], 6);
+    assert_eq!(print_params(&bs, &[1, 3])["layout"], "handouts");
+}

crates/ui-egui/src/canvas.rs

@@ -216,7 +216,7 @@ pub fn ime_area(app: &SlideApp, xf: Xf) -> Option<Rect> {
 /// separate jamo (ㅇ ㅏ ㄴ) instead of syllables. A focused text field sets its own.
 fn ime_output(app: &SlideApp, ui: &Ui, xf: Xf) {
     let ctx = ui.ctx();
-    if ctx.memory(|m| m.focused().is_some()) || app.dialog.as_ref().is_some_and(|d| d.modal()) || app.palette.is_some() || app.home_open() {
+    if ctx.memory(|m| m.focused().is_some()) || app.dialog.as_ref().is_some_and(|d| d.modal()) || app.palette.is_some() || app.backstage_open() {
         return;
     }
     let Some(r) = ime_area(app, xf) else { return };

crates/ui-egui/src/control.rs

@@ -73,7 +73,8 @@ pub fn inspect(app: &SlideApp, ctx: &egui::Context) -> Value {
         "slideRect": app.slide_rect.map(|c| json!([c.left(), c.top(), c.width(), c.height()])),
         "canvasScale": app.canvas_scale,
         "dialog": app.dialog.as_ref().map(|d| d.id.clone()),
-        "home": app.home_open(),
+        "home": app.backstage_open(),
+        "backstage": app.backstage.as_ref().map(|b| b.page.id()),
         "showing": app.show.as_ref().map(|s| json!({"slide": s.state.slide, "step": s.state.step, "ended": s.ended})),
         "documents": app.session.documents().iter().map(|d| json!({"title": d.title(), "dirty": d.is_dirty(), "path": d.path})).collect::<Vec<_>>(),
         "status": app.status.as_ref().map(|s| s.0.clone()),

crates/ui-egui/src/dialogs.rs

@@ -1,11 +1,11 @@
-//! Dialogs (Insert Table, Slide Size, Header & Footer, Hyperlink, Set Up Show, Zoom, …), the start
-//! screen and the About window.
+//! Dialogs (Insert Table, Slide Size, Header & Footer, Hyperlink, Set Up Show, Zoom, …) and the
+//! About window. The start screen is File › Home (`backstage.rs`).
 
 use egui::{Align2, Color32, CornerRadius, Rect, Sense, Stroke, Ui, pos2, vec2};
 use serde_json::{Value, json};
 
+use crate::SlideApp;
 use crate::theme::{self, Tokens};
-use crate::{SlideApp, ribbon};
 
 #[derive(Clone, Debug, serde::Serialize)]
 pub struct Dialog {
@@ -290,6 +290,37 @@ fn body(app: &mut SlideApp, ui: &mut Ui, d: &mut Dialog) -> bool {
             });
             done
         }
+        "close" => {
+            // File › Close and Ctrl+W on a presentation with unsaved changes.
+            let Some(name) = app.session.active().map(|d| d.title()) else { return true };
+            ui.label(egui::RichText::new(format!("Do you want to save the changes you made to “{name}”?")).strong());
+            ui.label("Your changes will be lost if you don't save them.");
+            ui.add_space(8.0);
+            let mut done = false;
+            ui.horizontal(|ui| {
+                let t = Tokens::get(ui.ctx());
+                if ui.add(egui::Button::new("Don't Save").min_size(vec2(84.0, 24.0))).clicked() {
+                    run(app, "file.close", json!({}));
+                    done = true;
+                }
+                ui.with_layout(egui::Layout::right_to_left(egui::Align::Center), |ui| {
+                    let save = ui.add(egui::Button::new(egui::RichText::new("Save").color(t.accent_text)).fill(t.accent).min_size(vec2(72.0, 24.0)));
+                    if save.clicked() || ui.input(|i| i.key_pressed(egui::Key::Enter)) {
+                        app.save();
+                        // In the browser a save is a download: the presentation stays "unsaved".
+                        let web = app.services.pick_save.is_none() && app.services.download.is_some();
+                        if web || app.session.active().is_some_and(|d| !d.is_dirty()) {
+                            run(app, "file.close", json!({}));
+                        }
+                        done = true;
+                    }
+                    if ui.add(egui::Button::new("Cancel").min_size(vec2(72.0, 24.0))).clicked() {
+                        done = true;
+                    }
+                });
+            });
+            done
+        }
         "zoom" => {
             for pct in [400, 200, 150, 100, 75, 66, 50, 33] {
                 if ui.radio(false, format!("{pct}%")).clicked() {
@@ -430,45 +461,8 @@ fn body(app: &mut SlideApp, ui: &mut Ui, d: &mut Dialog) -> bool {
             };
             let (ok, cancel) = buttons(ui, "Export");
             if ok {
-                let name = app.session.active().map(|s| s.title()).unwrap_or_else(|| "Presentation".into());
-                let (ext, all) = match fmt.as_str() {
-                    "pdf" => ("pdf", false),
-                    "pngAll" => ("png", true),
-                    "jpeg" => ("jpg", false),
-                    "pptx" => ("pptx", false),
-                    "outline" => ("txt", false),
-                    _ => ("png", false),
-                };
-                let suggested = format!("{name}.{ext}");
-                if let Some(pick) = app.services.pick_save.as_mut() {
-                    if let Some(path) = pick(&suggested) {
-                        let mut params = json!({"path": path, "all": all});
-                        if ext == "pdf"
-                            && let (Some(o), Some(extra)) = (params.as_object_mut(), pdf_params.as_object())
-                        {
-                            o.extend(extra.clone());
-                        }
-                        let r = app.session.execute("file.export", &params);
-                        match r {
-                            Ok(_) => app.set_status(format!("Exported {path}")),
-                            Err(e) => app.set_status(e.to_string()),
-                        }
-                    }
-                } else if let (Some(dl), Some(s)) = (app.services.download.as_mut(), app.session.active()) {
-                    let bytes = match ext {
-                        "png" | "jpg" => {
-                            let img = deckcraft_render::render_slide(
-                                &s.doc,
-                                s.selection.slide,
-                                &deckcraft_render::RenderOpts { scale: 2.0, ..Default::default() },
-                            );
-                            if ext == "png" { img.to_png() } else { img.to_jpeg(92) }
-                        }
-                        "pdf" => deckcraft_pdf_bytes(&s.doc, &pdf_params),
-                        other => deckcraft_engine::cmd::file::save_bytes(&s.doc, other).unwrap_or_default(),
-                    };
-                    dl(&suggested, &bytes);
-                }
+                let extra = if fmt == "pdf" { pdf_params } else { json!({}) };
+                app.export_as(&fmt, extra);
             }
             ok || cancel
         }
@@ -835,129 +829,3 @@ pub fn paint_logo(p: &egui::Painter, r: Rect) {
         Stroke::NONE,
     ));
 }
-
-/// The start screen (no presentation open): new from themes, open, recent files.
-pub fn start_screen(app: &mut SlideApp, ui: &mut Ui) {
-    let t = Tokens::get(ui.ctx());
-    egui::ScrollArea::vertical().show(ui, |ui| {
-        ui.add_space(24.0);
-        ui.horizontal(|ui| {
-            ui.add_space(40.0);
-            let (r, _) = ui.allocate_exact_size(vec2(40.0, 40.0), Sense::hover());
-            paint_logo(ui.painter(), r);
-            ui.label(egui::RichText::new("DeckCraft").font(theme::bold(26.0)));
-        });
-        if app.home_open() {
-            let title = app.session.active().map(|d| d.title()).unwrap_or_default();
-            ui.add_space(8.0);
-            ui.horizontal(|ui| {
-                ui.add_space(40.0);
-                if ui.button(format!("← Back to {title}")).on_hover_text("Esc").clicked() {
-                    let _ = app.run("app.home", json!({"on": false}));
-                }
-            });
-        }
-        ui.add_space(16.0);
-        ui.horizontal(|ui| {
-            ui.add_space(40.0);
-            ui.label(egui::RichText::new("New presentation").font(theme::bold(16.0)));
-        });
-        ui.add_space(8.0);
-        inset_wrapped(ui, |ui| {
-            for th in deckcraft_model::theme::builtin_themes() {
-                let (r, resp) = ui.allocate_exact_size(vec2(180.0, 128.0), Sense::click());
-                let tile = Rect::from_min_size(r.min, vec2(180.0, 101.0));
-                ribbon::paint_theme_tile(ui.painter(), tile, &th);
-                if resp.hovered() {
-                    ui.painter().rect_stroke(tile, CornerRadius::same(2), Stroke::new(2.0, t.accent), egui::StrokeKind::Outside);
-                }
-                ui.painter().text(pos2(r.min.x, r.max.y - 10.0), Align2::LEFT_CENTER, &th.name, theme::font(12.0), t.text);
-                if resp.clicked() {
-                    let _ = app.run("file.new", json!({"theme": th.name}));
-                }
-            }
-        });
-        ui.add_space(16.0);
-        ui.horizontal(|ui| {
-            ui.add_space(40.0);
-            if ui.button("Open…").clicked() {
-                let _ = app.run("app.openDialog", json!({}));
-            }
-            if ui.button("Open the sample deck").clicked()
-                && let Err(e) = deckcraft_engine::sample::open_sample(&mut app.session)
-            {
-                app.set_status(e.to_string());
-            }
-        });
-        if !app.ui.recent.is_empty() {
-            ui.add_space(16.0);
-            ui.horizontal(|ui| {
-                ui.add_space(40.0);
-                ui.label(egui::RichText::new("Recent").font(theme::bold(16.0)));
-            });
-            for p in app.ui.recent.clone() {
-                ui.horizontal(|ui| {
-                    ui.add_space(40.0);
-                    if ui.link(&p).clicked()
-                        && let Err(e) = app.open_path(&p)
-                    {
-                        app.set_status(e);
-                    }
-                });
-            }
-        }
-        ui.add_space(30.0);
-        ui.horizontal(|ui| {
-            ui.add_space(40.0);
-            ui.hyperlink_to("Join the ArtCraft community on Discord", deckcraft_engine::links::DISCORD);
-        });
-    });
-}
-
-/// Wrapped rows that all start 40 points in from the left, in line with the start screen's
-/// headings. The inset is a margin on the container: an `add_space` inside `horizontal_wrapped`
-/// would indent only the first row.
-fn inset_wrapped(ui: &mut Ui, add_contents: impl FnOnce(&mut Ui)) {
-    egui::Frame::NONE.inner_margin(egui::Margin { left: 40, ..Default::default() }).show(ui, |ui| {
-        ui.horizontal_wrapped(add_contents);
-    });
-}
-
-/// PDF bytes with the export dialog's options (web: downloaded instead of written).
-fn deckcraft_pdf_bytes(doc: &deckcraft_model::Presentation, params: &serde_json::Value) -> Vec<u8> {
-    deckcraft_engine::cmd::file::pdf_bytes(doc, params).unwrap_or_default()
-}
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-    use std::cell::{Cell, RefCell};
-
-    /// Start screen theme tiles that wrap onto a second row keep the 40-point inset (#17).
-    #[test]
-    fn inset_wrapped_indents_every_row() {
-        let left = Cell::new(0.0_f32);
-        let tiles = RefCell::new(Vec::<Rect>::new());
-        let mut harness = egui_kittest::Harness::builder().with_size(vec2(500.0, 400.0)).build_ui(|ui| {
-            left.set(ui.max_rect().left());
-            tiles.borrow_mut().clear();
-            inset_wrapped(ui, |ui| {
-                for _ in 0..4 {
-                    let (r, _) = ui.allocate_exact_size(vec2(180.0, 128.0), Sense::click());
-                    tiles.borrow_mut().push(r);
-                }
-            });
-        });
-        harness.run();
-        let tiles = tiles.borrow().clone();
-        let first_top = tiles.first().map_or(0.0, |r| r.top());
-        assert!(tiles.iter().any(|r| r.top() > first_top), "tiles should wrap onto a second row: {tiles:?}");
-        let mut row_top = f32::NEG_INFINITY;
-        for r in &tiles {
-            if r.top() > row_top {
-                row_top = r.top();
-                assert!((r.left() - (left.get() + 40.0)).abs() < 0.5, "row starts at {} instead of {}", r.left(), left.get() + 40.0);
-            }
-        }
-    }
-}

crates/ui-egui/src/fillui.rs

@@ -16,6 +16,7 @@ pub fn default_gradient(base: ColorRef, angle: f64) -> Gradient {
     let mut dark = base.clone();
     dark.mods.push(ColorTransform::LumMod(60_000));
     Gradient {
+        tile: [0.0; 4],
         stops: vec![GradientStop { pos: 0.0, color: base }, GradientStop { pos: 1.0, color: dark }],
         shape: GradientShape::Linear { angle, scaled: false },
         rotate_with_shape: true,
@@ -136,6 +137,7 @@ pub fn gradient_editor(ui: &mut Ui, id: &str, g: &Gradient, sc: &ColorScheme) ->
                 ..default_gradient(base.clone(), 45.0)
             },
             Gradient {
+                tile: [0.0; 4],
                 stops: vec![GradientStop { pos: 0.0, color: light }, GradientStop { pos: 1.0, color: dark }],
                 shape: GradientShape::Path { path: "circle".into(), focus: [0.5, 0.5, 0.5, 0.5] },
                 rotate_with_shape: true,

crates/ui-egui/src/icons.rs

@@ -306,6 +306,13 @@ icons! {
     Collapse => "collapse",
     Expand => "expand",
     Pin => "pin",
+    // File tab (Backstage)
+    BackCircle => "back-circle",
+    SaveAs => "save-as",
+    Account => "account",
+    Recent => "recent",
+    NewFile => "new-file",
+    OpenFolder => "open-folder",
     // Status bar (small, monochrome)
     NotesSmall => "notes-small",
     CommentsSmall => "comments-small",
@@ -2361,6 +2368,33 @@ fn draw(p: &Pen<'_>, icon: Icon) {
             p.rshape(&m(&[(-4.2, -10.0), (4.2, -10.0), (4.2, -7.0), (-4.2, -7.0)]), 0.6, R, N);
         }
 
+        // ----- File tab (Backstage) navigation: outlines in the ink colour -----
+        I::BackCircle => {
+            p.circle((12.0, 12.0), 9.8, N, K);
+            p.arrow((17.0, 12.0), (6.5, 12.0), K);
+        }
+        I::SaveAs => {
+            p.rline(&[(11.0, 20.5), (2.5, 20.5), (2.5, 3.0), (15.0, 3.0), (18.0, 6.0), (18.0, 10.5)], 1.2, K);
+            p.rect(6.0, 3.0, 13.0, 7.5, 0.6, N, K);
+            p.seg_w((13.5, 21.0), (21.5, 13.0), O, 1.4);
+            p.seg_w((12.5, 22.0), (13.5, 21.0), K, 1.0);
+        }
+        I::Account => {
+            p.circle((12.0, 8.0), 4.5, N, K);
+            p.line(&arc_pts((12.0, 22.0), 8.5, 7.5, 180.0, 360.0), K);
+        }
+        I::Recent => {
+            p.circle((12.0, 12.0), 9.8, N, K);
+            p.line(&[(12.0, 6.0), (12.0, 12.0), (16.0, 14.5)], K);
+        }
+        I::NewFile => {
+            p.rline(&[(14.0, 2.5), (5.0, 2.5), (5.0, 21.5), (19.0, 21.5), (19.0, 7.5), (14.0, 2.5), (14.0, 7.5), (19.0, 7.5)], 0.8, K);
+        }
+        I::OpenFolder => {
+            p.rline(&[(18.5, 9.0), (18.5, 6.5), (10.0, 6.5), (8.0, 4.0), (2.5, 4.0), (2.5, 19.5), (18.0, 19.5)], 1.0, K);
+            p.rline(&[(2.5, 19.5), (6.0, 10.0), (22.0, 10.0), (18.0, 19.5)], 1.0, K);
+        }
+
         // ----- Status bar (monochrome) -----
         I::NotesSmall => {
             p.rect(3.0, 4.0, 21.0, 20.0, 1.5, N, K);

crates/ui-egui/src/lib.rs

@@ -6,6 +6,7 @@
 #![deny(clippy::unwrap_used, clippy::expect_used, clippy::panic, clippy::unimplemented, clippy::todo, clippy::unreachable)]
 #![forbid(unsafe_code)]
 
+pub mod backstage;
 pub mod canvas;
 pub mod control;
 pub mod credits;
@@ -154,6 +155,9 @@ pub const UI_COMMANDS: &[(&str, &str, Option<&str>, &str)] = &[
     ("show.presenter", "Presenter View", None, "{on?: bool}"),
     ("show.end", "End Show", None, "{}"),
     ("app.home", "Home", None, "{on?}"),
+    ("app.backstage", "File", Some("Alt+F"), "{page?: home|new|open|info|saveAs|print|export|account, on?: bool}"),
+    ("app.closePresentation", "Close", Some("Cmd+W"), "{}"),
+    ("app.print", "Print", Some("Cmd+P"), "{layout?, perPage?, slides?, includeHidden?, frame?}"),
     ("app.about", "About DeckCraft", None, "{}"),
     ("app.palette", "Command Palette", Some("Cmd+Shift+P"), "{}"),
     ("app.preferences", "Preferences…", Some("Cmd+,"), "{}"),
@@ -200,9 +204,10 @@ pub struct SlideApp {
     pub palette: Option<(String, usize)>,
     /// Integrated title bar (macOS traffic lights over our chrome).
     pub integrated_titlebar: bool,
-    /// The start screen is shown over the open presentations (Home), with the document count
-    /// and active index when it was opened: opening or creating a presentation leaves it.
-    pub home: Option<(usize, Option<usize>)>,
+    /// The File tab's full-window view (Backstage). Over a presentation it replaces the ribbon,
+    /// slides and status bar until Esc or Back; with nothing open it is the start screen. Opening,
+    /// creating or closing a presentation leaves it.
+    pub backstage: Option<backstage::Backstage>,
     pending_urls: Vec<String>,
     shot_token: u64,
     queued_shots: Vec<(u64, f64, u32)>,
@@ -247,7 +252,7 @@ impl SlideApp {
             canvas_region: None,
             palette: None,
             integrated_titlebar: false,
-            home: None,
+            backstage: None,
             pending_urls: vec![],
             shot_token: 0,
             queued_shots: vec![],
@@ -289,13 +294,153 @@ impl SlideApp {
         r
     }
 
-    fn docs_key(&self) -> (usize, Option<usize>) {
+    pub(crate) fn docs_key(&self) -> (usize, Option<usize>) {
         (self.session.documents().len(), self.session.active_index())
     }
 
-    /// Home is open over a presentation (not just the start screen with nothing open).
-    pub fn home_open(&self) -> bool {
-        self.home.is_some() && self.session.active().is_some()
+    /// The File tab's view is open over a presentation (not just the start screen with nothing
+    /// open).
+    pub fn backstage_open(&self) -> bool {
+        self.backstage.is_some() && self.session.active().is_some()
+    }
+
+    /// Opens the File tab's view on `page` (keeping its state when it is already open).
+    pub fn open_backstage(&mut self, page: backstage::Page) {
+        let key = self.docs_key();
+        match &mut self.backstage {
+            Some(b) => b.go(page),
+            None => self.backstage = Some(backstage::Backstage::new(page, key)),
+        }
+    }
+
+    /// Back to the presentation (no effect on the start screen, where nothing is open).
+    pub fn close_backstage(&mut self) {
+        if self.session.active().is_some() {
+            self.backstage = None;
+        }
+    }
+
+    /// Keeps the File tab's view in step with the open presentations: it closes when one is
+    /// opened, created or closed (the result shows), and it is the start screen when none is open.
+    fn sync_backstage(&mut self) {
+        let key = self.docs_key();
+        let has_doc = self.session.active().is_some();
+        let stale = self.backstage.as_ref().is_some_and(|b| b.docs != key);
+        if has_doc && stale {
+            self.backstage = None;
+        } else if !has_doc && (stale || self.backstage.is_none()) {
+            self.backstage = Some(backstage::Backstage::new(backstage::Page::Home, key));
+        }
+    }
+
+    /// File › Close and Ctrl+W: closes the active presentation, asking first when it has unsaved
+    /// changes (Save, Don't Save, Cancel), as PowerPoint does.
+    pub fn close_presentation(&mut self) {
+        match self.session.active() {
+            None => {}
+            Some(d) if d.is_dirty() => self.dialog = Some(dialogs::Dialog::new("close")),
+            Some(_) => {
+                let _ = self.run("file.close", json!({}));
+            }
+        }
+    }
+
+    /// The file name a save or export suggests: the presentation's title with `ext`.
+    fn suggested_name(&self, ext: &str) -> String {
+        let name = self.session.active().map(|d| d.title()).unwrap_or_else(|| "Presentation".into());
+        format!("{name}.{ext}")
+    }
+
+    /// Exports the active presentation as `fmt` (`pdf`, `png`, `pngAll`, `jpeg`, `pptx`,
+    /// `deckcraft`, `outline`) through `file.export`: the save picker on the desktop, a download
+    /// on the web. `extra` adds `file.export` params (the PDF's layout, slides…). The
+    /// presentation keeps its own file. Returns whether a file was written or handed over.
+    pub fn export_as(&mut self, fmt: &str, extra: Value) -> bool {
+        let Some(slide) = self.session.active().map(|d| d.selection.slide) else { return false };
+        let (ext, format, all) = match fmt {
+            "pdf" => ("pdf", "pdf", false),
+            "png" => ("png", "png", false),
+            "pngAll" => ("png", "png", true),
+            "jpeg" | "jpg" => ("jpg", "jpeg", false),
+            "pptx" => ("pptx", "pptx", false),
+            "outline" | "txt" => ("txt", "outline", false),
+            "deckcraft" => ("deckcraft", "deckcraft", false),
+            other => {
+                self.set_status(format!("DeckCraft can't export “{other}”"));
+                return false;
+            }
+        };
+        let suggested = self.suggested_name(ext);
+        if let Some(pick) = self.services.pick_save.as_mut() {
+            let Some(path) = pick(&suggested) else { return false };
+            let mut params = json!({"path": path, "format": format, "all": all});
+            if let (Some(o), Some(x)) = (params.as_object_mut(), extra.as_object()) {
+                o.extend(x.clone());
+            }
+            return match self.run("file.export", params) {
+                Ok(_) => {
+                    self.set_status(format!("Exported {path}"));
+                    true
+                }
+                Err(_) => false,
+            };
+        }
+        let Some(doc) = self.session.active().map(|d| d.doc.clone()) else { return false };
+        let bytes = match format {
+            "png" | "jpeg" => {
+                let img = deckcraft_render::render_slide(&doc, slide, &deckcraft_render::RenderOpts { scale: 2.0, ..Default::default() });
+                Ok(if format == "png" { img.to_png() } else { img.to_jpeg(92) })
+            }
+            "pdf" => deckcraft_engine::cmd::file::pdf_bytes(&doc, &extra),
+            other => deckcraft_engine::cmd::file::save_bytes(&doc, other),
+        };
+        self.download(&suggested, bytes)
+    }
+
+    /// Hands `bytes` to the browser as a download (web); false (with the reason in the status
+    /// bar) when there are no bytes or no way to download.
+    fn download(&mut self, name: &str, bytes: deckcraft_engine::Result<Vec<u8>>) -> bool {
+        match (bytes, self.services.download.as_mut()) {
+            (Ok(b), Some(dl)) => {
+                dl(name, &b);
+                true
+            }
+            (Err(e), _) => {
+                self.set_status(e.to_string());
+                false
+            }
+            (Ok(_), None) => {
+                self.set_status("Saving a copy needs a file picker, which this window doesn't have.");
+                false
+            }
+        }
+    }
+
+    /// File › Print: DeckCraft prints through a PDF. On the desktop the PDF (with the Print page's
+    /// layout, slides and options) is written to the temporary folder and opened in the system's
+    /// PDF viewer, which has the printers; on the web it downloads.
+    pub fn print_pdf(&mut self, params: Value) -> bool {
+        let Some((title, doc)) = self.session.active().map(|d| (d.title(), d.doc.clone())) else { return false };
+        let mut params = if params.is_object() { params } else { json!({}) };
+        if self.services.pick_save.is_none() {
+            // Web: the browser hands the PDF to the user.
+            let bytes = deckcraft_engine::cmd::file::pdf_bytes(&doc, &params);
+            return self.download(&format!("{title}.pdf"), bytes);
+        }
+        let safe: String = title.chars().map(|c| if c.is_alphanumeric() || c == ' ' || c == '-' { c } else { '_' }).collect();
+        let path = std::env::temp_dir().join(format!("{safe} (print).pdf")).to_string_lossy().to_string();
+        if let Some(o) = params.as_object_mut() {
+            o.insert("path".into(), json!(path));
+            o.insert("format".into(), json!("pdf"));
+        }
+        match self.run("file.export", params) {
+            Ok(_) => {
+                self.open_url(&format!("file:///{}", path.replace('\\', "/").trim_start_matches('/')));
+                self.set_status("Opened the presentation as a PDF to print");
+                true
+            }
+            Err(_) => false,
+        }
     }
 
     fn flag(&mut self, params: &Value, cur: bool) -> bool {
@@ -358,8 +503,34 @@ impl SlideApp {
                 self.media.stop_owned(media::Owner::Show);
             }
             "app.home" => {
-                let on = self.flag(p, self.home.is_some());
-                self.home = (on && self.session.active().is_some()).then(|| self.docs_key());
+                let on = self.flag(p, self.backstage_open());
+                if on {
+                    self.open_backstage(backstage::Page::Home);
+                } else {
+                    self.close_backstage();
+                }
+            }
+            "app.backstage" => {
+                if !p.get("on").and_then(Value::as_bool).unwrap_or(true) {
+                    self.close_backstage();
+                    return Ok(json!({"page": self.backstage.as_ref().map(|b| b.page.id())}));
+                }
+                let page = match p.get("page").and_then(Value::as_str) {
+                    Some(id) => backstage::Page::parse(id).ok_or_else(|| format!("unknown File page `{id}`"))?,
+                    None => backstage::Page::Home,
+                };
+                if page.needs_doc() && self.session.active().is_none() {
+                    return Err(format!("File › {} needs an open presentation", page.label()));
+                }
+                self.open_backstage(page);
+                return Ok(json!({"page": page.id()}));
+            }
+            "app.closePresentation" => self.close_presentation(),
+            "app.print" => {
+                if self.session.active().is_none() {
+                    return Err("nothing to print: no presentation is open".into());
+                }
+                return Ok(json!({"printed": self.print_pdf(p.clone())}));
             }
             "app.about" => self.dialog = Some(dialogs::Dialog::new("about")),
             "app.palette" => self.palette = Some((String::new(), 0)),
@@ -678,16 +849,22 @@ impl SlideApp {
             return;
         }
         let events = ctx.input(|i| i.events.clone());
-        if self.home_open() {
-            // Only app shortcuts (Open, Command Palette…) and Escape, which goes back to the
-            // presentation: typing, pasting or deleting would edit the hidden presentation.
+        if self.backstage.is_some() {
+            // The File tab: its own keys (Esc goes back, arrows walk the side menu) and app
+            // shortcuts (New, Open, Command Palette…); typing, pasting or deleting would edit the
+            // hidden presentation.
             for e in events {
                 if let egui::Event::Key { key, pressed: true, modifiers, .. } = e {
                     let mods = Mods { shift: modifiers.shift, alt: modifiers.alt, cmd: modifiers.command || modifiers.ctrl };
-                    if key == egui::Key::Escape {
-                        self.home = None;
-                    } else if mods.cmd || mods.alt {
-                        menus::ui_shortcut(self, key, mods);
+                    if backstage::key(self, key, mods) || !(mods.cmd || mods.alt) || menus::ui_shortcut(self, key, mods) {
+                        continue;
+                    }
+                    // Engine shortcuts that don't touch the hidden slide (Ctrl+N).
+                    if mods.cmd
+                        && matches!(key, egui::Key::N)
+                        && let Err(e) = self.session.key(key_name(key), mods)
+                    {
+                        self.set_status(e.to_string());
                     }
                 }
             }
@@ -763,18 +940,21 @@ impl SlideApp {
             self.perf.frame_ms = now_ms() - t0;
             return;
         }
-        if self.home.is_some_and(|k| k != self.docs_key()) {
-            self.home = None;
-        }
+        self.sync_backstage();
         self.keyboard(&ctx);
+        self.sync_backstage();
         ribbon::title_bar(self, ui);
-        if self.session.active().is_some() && !self.home_open() {
+        if self.backstage.is_none() && self.session.active().is_some() {
             ribbon::show(self, ui);
             status::status_bar(self, ui);
         }
         egui::CentralPanel::default().frame(egui::Frame::NONE.fill(t.chrome)).show(ui, |ui| {
-            if self.session.active().is_none() || self.home_open() {
-                dialogs::start_screen(self, ui);
+            if self.backstage.is_some() {
+                // File tab: the Backstage view replaces everything below the title bar.
+                backstage::show(self, ui);
+                return;
+            }
+            if self.session.active().is_none() {
                 return;
             }
             match self.ui.view {
@@ -1010,7 +1190,7 @@ mod tests {
 
         harness.state_mut().run("app.home", json!({})).unwrap();
         harness.run_steps(2);
-        assert!(harness.state().home_open());
+        assert!(harness.state().backstage_open());
         assert_eq!(harness.state().session.documents().len(), 1, "Home doesn't create a presentation");
 
         // Typing on the start screen doesn't reach the presentation behind it; Escape goes back.
@@ -1021,18 +1201,18 @@ mod tests {
         assert!(!harness.state().session.active().unwrap().is_dirty());
         harness.key_press(egui::Key::Escape);
         harness.run_steps(2);
-        assert!(!harness.state().home_open());
+        assert!(!harness.state().backstage_open());
 
         // Home again toggles; picking a theme on the start screen (a new presentation) leaves it.
         harness.state_mut().run("app.home", json!({})).unwrap();
         harness.run_steps(2);
-        assert!(harness.state().home_open());
+        assert!(harness.state().backstage_open());
         harness.state_mut().run("app.home", json!({})).unwrap();
-        assert!(!harness.state().home_open());
+        assert!(!harness.state().backstage_open());
         harness.state_mut().run("app.home", json!({"on": true})).unwrap();
         harness.state_mut().run("file.new", json!({})).unwrap();
         harness.run_steps(2);
-        assert!(!harness.state().home_open(), "a new presentation leaves Home");
+        assert!(!harness.state().backstage_open(), "a new presentation leaves Home");
         assert_eq!(harness.state().session.documents().len(), 2);
     }
 
@@ -1123,7 +1303,7 @@ mod tests {
     fn home_needs_an_open_presentation() {
         let mut app = SlideApp::new(Session::new(), Services::default());
         app.run("app.home", json!({})).unwrap();
-        assert!(!app.home_open() && app.home.is_none(), "with nothing open the start screen shows anyway");
+        assert!(!app.backstage_open(), "with nothing open the start screen shows anyway");
     }
     fn canvas_harness() -> egui_kittest::Harness<'static, SlideApp> {
         let mut harness = egui_kittest::Harness::builder().with_size(egui::vec2(1200.0, 800.0)).build_ui_state(

crates/ui-egui/src/menus.rs

@@ -29,6 +29,25 @@ pub fn ui_shortcut(app: &mut SlideApp, key: egui::Key, m: Mods) -> bool {
             return true;
         }
         (S, true, true, false) => "app.saveAsDialog",
+        // File tab: Alt+F opens it on Home with the keyboard in its side menu; Ctrl+P on Print.
+        (F, false, false, true) => {
+            app.open_backstage(crate::backstage::Page::Home);
+            if let Some(b) = app.backstage.as_mut() {
+                b.focus = Some(0);
+            }
+            return true;
+        }
+        (P, true, false, false) => {
+            if app.session.active().is_none() {
+                return false;
+            }
+            app.open_backstage(crate::backstage::Page::Print);
+            return true;
+        }
+        (W, true, false, false) => {
+            app.close_presentation();
+            return true;
+        }
         (O, true, false, false) => "app.openDialog",
         (P, true, true, false) => "app.palette",
         (Comma, true, false, false) => "app.preferences",
@@ -133,10 +152,11 @@ pub fn menu_tree() -> Vec<(&'static str, Vec<(&'static str, &'static str)>)> {
                 ("New Presentation", "file.new"),
                 ("Open…", "app.openDialog"),
                 ("-", ""),
-                ("Close", "file.close"),
+                ("Close", "app.closePresentation"),
                 ("Save", "file.save"),
                 ("Save As…", "app.saveAsDialog"),
                 ("Export…", "app.exportDialog"),
+                ("Print…", "app.print"),
                 ("-", ""),
                 ("Properties", "file.properties"),
             ],

crates/ui-egui/src/ribbon.rs

@@ -47,7 +47,7 @@ pub fn title_bar(app: &mut SlideApp, ui: &mut Ui) {
         child.spacing_mut().item_spacing.x = 2.0;
         let has_doc = app.session.active().is_some();
         let dirty = app.session.active().is_some_and(|d| d.is_dirty());
-        if icon_toggle(&mut child, Icon::Home, "Home", true, app.home_open()).clicked() {
+        if icon_toggle(&mut child, Icon::Home, "Home", true, app.backstage_open()).clicked() {
             let _ = app.run("app.home", json!({}));
         }
         if icon_toggle(&mut child, Icon::Save, "Save (⌘S)", has_doc, false).clicked() {
@@ -143,9 +143,24 @@ pub fn show(app: &mut SlideApp, ui: &mut Ui) {
     let h = 28.0 + if app.ui.ribbon_collapsed { 4.0 } else { RIBBON_H + 20.0 };
     egui::Panel::top("ribbon").exact_size(h).frame(egui::Frame::NONE.fill(t.chrome)).show(ui, |ui| {
         let rect = ui.max_rect();
-        // Tabs.
+        // Tabs. File comes first and opens the File tab's full-window view (Backstage), as in
+        // PowerPoint.
         let mut x = rect.min.x + 12.0;
         let y = rect.min.y + 2.0;
+        {
+            let w = ui.fonts_mut(|f| f.layout_no_wrap("File".to_string(), theme::font(13.0), t.text).size().x) + 18.0;
+            let r = Rect::from_min_size(pos2(x, y), vec2(w, 24.0));
+            let resp = ui.interact(r, ui.id().with("tab_file"), Sense::click());
+            resp.widget_info(|| egui::WidgetInfo::labeled(egui::WidgetType::Button, true, "File"));
+            if resp.hovered() {
+                ui.painter().rect_filled(r.shrink2(vec2(2.0, 2.0)), CornerRadius::same(4), t.hover);
+            }
+            ui.painter().text(r.center(), Align2::CENTER_CENTER, "File", theme::font(13.0), t.text);
+            if resp.on_hover_text("File (Alt+F)").clicked() {
+                app.open_backstage(crate::backstage::Page::Home);
+            }
+            x += w + 2.0;
+        }
         let all: Vec<(&str, bool)> = TABS.iter().map(|s| (*s, false)).chain(ctx_tabs.iter().map(|s| (*s, true))).collect();
         for (name, contextual) in all {
             let font = theme::font(13.0);
@@ -1367,7 +1382,7 @@ fn transitions(app: &mut SlideApp, ui: &mut Ui) {
         let r = big_button(ui, Icon::EffectOptions, "Effect\nOptions", !opts.is_empty());
         egui::Popup::menu(&r).show(|ui| {
             for o in opts {
-                if ui.button(option_label(o)).clicked() {
+                if ui.button(deckcraft_model::anim::transition_option_label(&kind, o)).clicked() {
                     run(app, "transition.options", json!({"option": o}));
                 }
             }

crates/ui-egui/src/show.rs

@@ -61,6 +61,10 @@ struct Transition {
     /// The slide left behind (Morph matches its shapes) and the Morph frame texture.
     from: Option<usize>,
     morph: Option<TextureHandle>,
+    /// Backgrounds and contents of the old and new slides, rendered once when the transition
+    /// moves contents over backgrounds (Pan, Ferris Wheel, Reveal…): old back, old content, new
+    /// back, new content.
+    parts: Option<[Option<TextureHandle>; 4]>,
     start: f64,
     kind: String,
     option: String,
@@ -138,7 +142,7 @@ impl Show {
                     self.last_viewed = from;
                 }
                 self.trans = if kind != "none" && dur > 0.0 && !doc.show.without_animation {
-                    Some(Transition { old, from, morph: None, start: now, kind, option, dur })
+                    Some(Transition { old, from, morph: None, parts: None, start: now, kind, option, dur })
                 } else {
                     None
                 };
@@ -202,24 +206,43 @@ fn fit(avail: Rect, doc: &Presentation) -> Rect {
     Rect::from_center_size(avail.center(), vec2(sw * s, sh * s))
 }
 
+/// A transition layer as an egui mesh: [`deckcraft_anim::layer_mesh`]'s triangles (perspective
+/// cards subdivided so their pictures stay straight) with per-vertex opacity.
 fn quad_mesh(tex: Option<egui::TextureId>, rect: Rect, l: &Layer, color: Color32) -> Mesh {
     let mut m = match tex {
         Some(id) => Mesh::with_texture(id),
         None => Mesh::default(),
     };
-    let a = (l.alpha.clamp(0.0, 1.0) * 255.0) as u8;
-    let col = if tex.is_some() { Color32::from_white_alpha(a) } else { color.gamma_multiply(l.alpha.clamp(0.0, 1.0) as f32) };
-    for k in 0..4 {
-        let q = l.quad.get(k).copied().unwrap_or([0.0, 0.0]);
-        let uv = l.uv.get(k).copied().unwrap_or([0.0, 0.0]);
-        let p = pos2(rect.min.x + q[0] as f32 * rect.width(), rect.min.y + q[1] as f32 * rect.height());
-        m.vertices.push(egui::epaint::Vertex { pos: p, uv: pos2(uv[0] as f32, uv[1] as f32), color: col });
+    let (verts, tris) = deckcraft_anim::layer_mesh(l);
+    for v in &verts {
+        let a = if v.a.is_finite() { v.a.clamp(0.0, 1.0) } else { 0.0 };
+        let col = if tex.is_some() { Color32::from_white_alpha((a * 255.0).round() as u8) } else { color.gamma_multiply(a as f32) };
+        let p = pos2(rect.min.x + v.pos[0] as f32 * rect.width(), rect.min.y + v.pos[1] as f32 * rect.height());
+        m.vertices.push(egui::epaint::Vertex { pos: p, uv: pos2(v.uv[0] as f32, v.uv[1] as f32), color: col });
+    }
+    for t in tris {
+        m.add_triangle(t[0], t[1], t[2]);
     }
-    m.add_triangle(0, 1, 2);
-    m.add_triangle(0, 2, 3);
     m
 }
 
+/// Render the backgrounds and contents of a transition's two slides into textures, once.
+fn part_textures(ctx: &egui::Context, doc: &Presentation, from: Option<usize>, to: usize, size: (u32, u32)) -> [Option<TextureHandle>; 4] {
+    use deckcraft_render::SlidePart;
+    let threads = if cfg!(target_arch = "wasm32") { 0 } else { std::thread::available_parallelism().map(|n| n.get().min(8) as u16).unwrap_or(0) };
+    let opts = RenderOpts { scale: size.0 as f64 / doc.slide_size.width.max(1.0), size: Some(size), threads, ..Default::default() };
+    let tex = |i: usize, part: SlidePart, name: &str| {
+        let img = deckcraft_render::render_slide_part(doc, i, part, &opts);
+        ctx.load_texture(name, crate::textures::to_color_image(&img, false), egui::TextureOptions::LINEAR)
+    };
+    [
+        from.map(|i| tex(i, SlidePart::Backdrop, "trans-old-back")),
+        from.map(|i| tex(i, SlidePart::Content, "trans-old-content")),
+        Some(tex(to, SlidePart::Backdrop, "trans-new-back")),
+        Some(tex(to, SlidePart::Content, "trans-new-content")),
+    ]
+}
+
 pub fn ui(app: &mut SlideApp, ui: &mut Ui) {
     let ctx = ui.ctx().clone();
     let Some(doc) = app.session.active().map(|d| d.doc.clone()) else {
@@ -470,18 +493,37 @@ pub fn ui(app: &mut SlideApp, ui: &mut Ui) {
             tr.morph = Some(frame);
             drew = true;
             ctx.request_repaint();
-        } else if let (Some(tr), Some(new)) = (&show.trans, &tex) {
+        } else if let (Some(tr), Some(new)) = (show.trans.as_mut(), &tex) {
             let p = ((now - tr.start) / tr.dur.max(0.01)).clamp(0.0, 1.0);
             if p < 1.0 {
-                for l in deckcraft_anim::transition_layers(&tr.kind, &tr.option, p) {
+                // Slides split into background and content are rendered once per transition;
+                // every frame only composites cached textures.
+                if tr.parts.is_none() && deckcraft_anim::uses_slide_parts(&tr.kind, &tr.option) {
+                    tr.parts = Some(part_textures(&ctx, &doc, tr.from, idx, size));
+                }
+                let aspect = doc.slide_size.width / doc.slide_size.height.max(1.0);
+                let part = |k: usize| tr.parts.as_ref().and_then(|p| p.get(k).cloned().flatten());
+                let parts = [part(0), part(1), part(2), part(3)];
+                for l in deckcraft_anim::transition_frame(&tr.kind, &tr.option, p, aspect) {
+                    let old_or_black = |t: Option<&TextureHandle>| match t {
+                        Some(o) => quad_mesh(Some(o.id()), srect, &l, Color32::WHITE),
+                        None => quad_mesh(None, srect, &l, Color32::BLACK),
+                    };
                     let mesh = match l.source {
-                        Source::Old => match &tr.old {
-                            Some(o) => quad_mesh(Some(o.id()), srect, &l, Color32::WHITE),
-                            None => quad_mesh(None, srect, &l, Color32::BLACK),
-                        },
+                        Source::Old => old_or_black(tr.old.as_ref()),
                         Source::New => quad_mesh(Some(new.id()), srect, &l, Color32::WHITE),
                         Source::Black => quad_mesh(None, srect, &l, Color32::BLACK),
                         Source::White => quad_mesh(None, srect, &l, Color32::WHITE),
+                        Source::OldBack => old_or_black(parts[0].as_ref().or(tr.old.as_ref())),
+                        Source::NewBack => quad_mesh(Some(parts[2].as_ref().unwrap_or(new).id()), srect, &l, Color32::WHITE),
+                        Source::OldContent => match &parts[1] {
+                            Some(t) => quad_mesh(Some(t.id()), srect, &l, Color32::WHITE),
+                            None => continue,
+                        },
+                        Source::NewContent => match &parts[3] {
+                            Some(t) => quad_mesh(Some(t.id()), srect, &l, Color32::WHITE),
+                            None => continue,
+                        },
                     };
                     painter.add(egui::Shape::mesh(mesh));
                 }

docs/animation-parity.md

@@ -1,6 +1,6 @@
 # Transitions and animations: parity with PowerPoint
 
-> **Last reviewed:** 2026-10-10 · **Last updated:** 2026-10-10 · **Change:** major (created; effect lists counted from `crates/model/src/anim.rs` against PowerPoint 16.113's galleries) · **Target:** Microsoft PowerPoint for Mac 16.113 (Microsoft 365)
+> **Last reviewed:** 2026-10-13 · **Last updated:** 2026-10-13 · **Change:** major (transitions measured frame by frame against PowerPoint for Windows' video export and retuned; previous: created) · **Target:** Microsoft PowerPoint for Mac 16.113 (Microsoft 365)
 
 Transitions and animations are what make a deck a presentation, and the part of PowerPoint people
 notice first when it's missing. Scores roll up into [target-app-parity.md](target-app-parity.md)
@@ -9,14 +9,31 @@ notice first when it's missing. Scores roll up into [target-app-parity.md](targe
 ## Transitions: 48 of 48
 
 `crates/model/src/anim.rs` `TRANSITIONS` lists every transition in PowerPoint's gallery, in its
-three groups, with its Effect Options. All 48 round-trip through PPTX
-(`every_transition_kind_round_trips`), including the PowerPoint 2010+ `p14`/`p15` ones.
+three groups, with its Effect Options (now also Page Curl Single, Glitter Hexagons, Shred In/Out
+and Zoom and Rotate). All 48 round-trip through PPTX with the elements, attributes and defaults
+PowerPoint itself writes (`every_transition_kind_round_trips`,
+`transition_xml_matches_powerpoints_elements`, `transition_defaults_read_like_powerpoint`): 145 of
+145 PowerPoint-built test slides reopen in PowerPoint with the same effect after a DeckCraft
+save.
+
+**Measured against PowerPoint (2026-10-13).** Synthetic two-colour decks with asymmetric markers
+were built in PowerPoint for Windows over COM with every transition and option (150 variants,
+2 s each), exported with `CreateVideo` at 30 fps, and compared frame by frame with
+`deckcraft-cli render-transition` at the same progress (`plan/powerpoint/tools/synth_transitions.ps1`,
+`trans_compare.py`). Mean absolute difference over all variants at t = 0.1…0.9 (0–255): **35.7
+before, 15.0 after**. Curves (fades are a smoothstep, moves ease in-out; Cover, Uncover and Pan
+have their own measured curves), directions and option meanings (e.g. Glitter starts on the
+option's side, Ripple's corner is where the wave heads, Wind/Airplane/Origami "Left" is `invX`),
+soft edges (Wipe, Split, Shape, Clock, Ripple) and the Dynamic Content transitions moving the
+slides' contents over cross-fading backgrounds now follow PowerPoint. 3-D transitions are
+perspective-projected cards (`crates/anim/src/transition_geom.rs`) drawn with
+perspective-correct subdivided meshes.
 
 | Group | PowerPoint | DeckCraft | Fidelity |
 |---|---|---|---|
-| Subtle (Morph, Fade, Push, Wipe, Split, Reveal, Cut, Random Bars, Shape, Uncover, Cover, Flash) | 12 | 12 | 2-D, close to PowerPoint |
-| Exciting (Fall Over, Drape, Curtains, Wind, Prestige, Fracture, Crush, Peel Off, Page Curl, Airplane, Origami, Dissolve, Checkerboard, Blinds, Clock, Ripple, Honeycomb, Glitter, Vortex, Shred, Switch, Flip, Gallery, Cube, Doors, Box, Comb, Zoom, Random) | 29 | 29 | 3-D ones are fake 3-D (trapezoid quads, `crates/anim/src/transition.rs`); particle effects (Vortex, Shred, Fracture, Crush) approximate |
-| Dynamic Content (Pan, Ferris Wheel, Conveyor, Rotate, Window, Orbit, Fly Through) | 7 | 7 | Same approach |
+| Subtle (Morph, Fade, Push, Wipe, Split, Reveal, Cut, Random Bars, Shape, Uncover, Cover, Flash) | 12 | 12 | Matches PowerPoint's frames (mean diff 1–8; Random Bars and Reveal Through Black ~15) |
+| Exciting (Fall Over, Drape, Curtains, Wind, Prestige, Fracture, Crush, Peel Off, Page Curl, Airplane, Origami, Dissolve, Checkerboard, Blinds, Clock, Ripple, Honeycomb, Glitter, Vortex, Shred, Switch, Flip, Gallery, Cube, Doors, Box, Comb, Zoom, Random) | 29 | 29 | Perspective 3-D cards with measured motion; cloth, paper and particle effects (Curtains, Peel Off, Page Curl, Airplane, Origami, Fracture, Crush, Honeycomb, Vortex, Shred) are flat approximations of PowerPoint's meshes |
+| Dynamic Content (Pan, Ferris Wheel, Conveyor, Rotate, Window, Orbit, Fly Through) | 7 | 7 | Contents move over cross-fading backgrounds, as in PowerPoint (mean diff 5–17) |
 
 | Transition feature | PowerPoint | DeckCraft |
 |---|---|---|
@@ -28,7 +45,7 @@ three groups, with its Effect Options. All 48 round-trip through PPTX
 | Morph: Words and Characters | yes | yes (#5) |
 | Morph: geometry (circle to star) | yes | yes (#27) |
 | Morph: `!!` name forcing, pictures, 3-D models, ink | yes | names partly; no 3-D or ink |
-| Frame-by-frame comparison with PowerPoint | | **not done** |
+| Frame-by-frame comparison with PowerPoint | | done (Windows, 2026-10-13); headless frames: `deckcraft-cli render-transition` |
 
 ## Animations: 64 of ~190 effects
 
@@ -69,11 +86,12 @@ In, Wipe, Zoom, Float In, Grow/Shrink, Pulse, Spin, motion lines): weighted, ~85
 | Rewind and other effect options on round trip (#77) | 1–2 |
 | Transition sounds | 1–2 |
 | Morph across pictures, `!!` names, align once per transition (#67) | 2–4 |
-| Reference captures from PowerPoint for the 3-D transitions, then tuning | 2–4 |
-| **Total** | **~14–26** (the Transitions and Animations rows of the feature table; part of the Features dimension's 140–240 h) |
+| Cloth, paper and particle transitions as real meshes (Curtains, Peel Off, Page Curl, Airplane, Origami, Vortex, Shred, Honeycomb) | 4–8 |
+| **Total** | **~16–30** (the Transitions and Animations rows of the feature table; part of the Features dimension's 140–240 h) |
 
 ## Revision history
 
 | Date | Change | Summary |
 |---|---|---|
+| 2026-10-13 | major | Transitions measured frame by frame against PowerPoint's video export and retuned (mean diff 35.7 → 15.0); PowerPoint's XML defaults and option meanings; new options |
 | 2026-10-10 | major | Created: 48/48 transitions, 64 of ~190 animation effects, pane and option depth, estimates |

docs/architecture.md

@@ -1,6 +1,6 @@
 # DeckCraft architecture
 
-> **Last reviewed:** 2026-10-10 · **Last updated:** 2026-10-10 · **Change:** major (created from the code on main at d556ff9; AGENTS.md §4 keeps the rules) · **Target:** Microsoft PowerPoint for Mac 16.113 (Microsoft 365)
+> **Last reviewed:** 2026-10-13 · **Last updated:** 2026-10-13 · **Change:** minor (transition frames: perspective meshes, slide parts, headless compositor; previous: created from the code on main at d556ff9) · **Target:** Microsoft PowerPoint for Mac 16.113 (Microsoft 365)
 
 How DeckCraft is built today. The binding rules (layering, everything is a command, thin UI, never
 break wasm, never crash) are in [AGENTS.md](../AGENTS.md) §3–§5; this document describes what
@@ -49,8 +49,12 @@ Programmatic calls never open dialogs. Pointer gestures go through `Session::poi
 ## Rendering and the show
 
 The renderer draws a slide to an RGBA pixmap on the CPU; the UI uploads it as an egui texture.
-Transitions are layers of textured quads over the old and new slide images (fake 3-D from
-trapezoids). The show window and the presenter view are egui viewports; animation state per shape
+Transitions are layers of textured quads over the old and new slide images, or over their
+backgrounds and contents rendered apart (Dynamic Content), from `anim::transition_frame`: 3-D
+effects project cards through a perspective camera and `anim::layer_mesh` subdivides them so
+textures stay straight; soft edges are per-corner opacities. The show renders the slides once per
+transition and only composites cached textures each frame; `render::composite_transition` is the
+CPU twin used by `deckcraft-cli render-transition` and the tests. The show window and the presenter view are egui viewports; animation state per shape
 comes from `anim::timeline` each frame. PDF export renders each slide at print resolution and
 overlays an invisible real-text layer with embedded font subsets.
 
@@ -74,4 +78,5 @@ macOS, Windows, Linux, FreeBSD and web artifacts.
 
 | Date | Change | Summary |
 |---|---|---|
+| 2026-10-13 | minor | Transitions: perspective meshes, background/content parts, CPU compositor |
 | 2026-10-10 | major | Created from the code on main (d556ff9) and AGENTS.md §4 |

docs/control-protocol.md

@@ -15,7 +15,7 @@ Coordinates are slide points (1/72 inch; a 16:9 slide is 960 × 540) unless note
 | `engine.execute` / `ui.menu.invoke` / `command` | `{command, params}` | Run any command (see `engine.commands`; `deckcraft-cli describe ID` documents one) |
 | `engine.commands` | — | Every command: id, label, menu path, shortcut, params doc, enabled / disabled reason |
 | `document.inspect` | — | Slides, sections, layouts, shapes, selection |
-| `ui.inspect` | — | UI state, active tool, window/canvas/slide rects, dialog, Home (start screen over the open presentations), slide show state, documents, perf (fps, render ms) |
+| `ui.inspect` | — | UI state, active tool, window/canvas/slide rects, dialog, `home` (the File tab open over a presentation), `backstage` (its page, also the start screen), slide show state, documents, perf (fps, render ms) |
 | `ui.tool.select` | `{tool, preset?}` | `select`, `text`, `shape` + preset, any preset name, `curve`, `freeform`, `scribble`, `pen`, `highlighter`, `eraser` |
 | `ui.pointer` | `{events: [{kind: down\|drag\|up\|move\|doubleclick\|tripleclick, x, y, mods?}], mods?}` | Drive the active tool in slide points through the same code path as the mouse |
 | `ui.key` / `ui.text` | `{key, shift?, alt?, cmd?}` / `{text}` | Keyboard input (also drives a running slide show) |

docs/file-format-parity.md

@@ -63,7 +63,7 @@ the round trip even though DeckCraft doesn't model it.
 | Themes: colour, font (Latin/EA/CS), effect schemes, background styles | yes | yes | Unknown theme parts kept |
 | Notes slides and notes master | yes | yes | No notes-master editing view |
 | Handout master | no | no | |
-| Shapes: preset geometry (~180 presets), custom geometry, groups, connectors | yes | yes | Presets re-derived in `crates/geom/src/preset.rs` (and `preset/extra.rs`). Outlines, dashes, arrowheads and ink inside a group keep their width in points whatever the group's child-coordinate scale (#233); text in a group with a tiny child space is not drawn yet. |
+| Shapes: preset geometry (~180 presets), custom geometry, groups, connectors | yes | yes | Presets re-derived in `crates/geom/src/preset.rs` (and `preset/extra.rs`). Outlines, dashes, arrowheads and ink inside a group, and text, keep their size in points whatever the group's child-coordinate scale (#233). |
 | Fills: solid, gradient, picture (stretch/tile/crop), pattern, group | yes | yes | |
 | Lines: dash, compound, caps, joins, arrowheads | yes | yes | |
 | Effects: shadow, glow, soft edges, reflection | yes | yes | |

docs/gaps.md

@@ -1,6 +1,6 @@
 # Where DeckCraft falls short of PowerPoint
 
-> **Last reviewed:** 2026-10-10 · **Last updated:** 2026-10-12 · **Change:** minor (IME composition and CJK interface text landed, #101; previous: minor, core-workflow alpha gate added; stage stays alpha; before that: major, first itemized gap list; full re-measure against PowerPoint for Mac 16.113.4 and the open GitHub issues) · **Target:** Microsoft PowerPoint for Mac 16.113 (Microsoft 365)
+> **Last reviewed:** 2026-10-10 · **Last updated:** 2026-10-13 · **Change:** minor (3-D bevel, camera and face lighting rendered; previous: minor, IME composition and CJK interface text landed, #101; previous: minor, core-workflow alpha gate added; stage stays alpha; before that: major, first itemized gap list; full re-measure against PowerPoint for Mac 16.113.4 and the open GitHub issues) · **Target:** Microsoft PowerPoint for Mac 16.113 (Microsoft 365)
 
 Every known shortfall, one entry each, ranked by how much it stops someone who presents with
 PowerPoint from switching. This is the work list: pick from the top. Numbers are summarized in
@@ -168,10 +168,11 @@ Detail in [animation-parity.md](animation-parity.md). 10–16 h; the pane is a *
 - **Evidence:** checklist rows "Edit points" (P1 missing), "Text warp transforms" (partial: all 40
   `prstTxWarp` presets render and their adjusts round-trip, but there is no Transform gallery or
   command to apply one, no adjust handles, and arc/circle placement can differ from PowerPoint by
-  1–3 % of the path length), "Bevel and 3-D rotation" (missing; `scene3d`/`sp3d` kept as raw XML on
-  round trip).
-- **Estimate:** 4–6 h (edit points), 2–4 h (warp gallery, command and handles), 8–12 h (3-D render
-  approximation).
+  1–3 % of the path length), "Bevel and 3-D rotation" (partial: bevels, camera presets and rotations and face lighting
+  render as approximations and `scene3d`/`sp3d` round-trip as raw XML; no extrusion or side faces,
+  only the three-point rig, and no command or pane to apply 3-D).
+- **Estimate:** 4–6 h (edit points), 2–4 h (warp gallery, command and handles), 6–10 h (3-D extrusion,
+  rigs and materials, Format Shape page).
 
 ### Proofing: spelling, thesaurus, AutoCorrect
 - **Evidence:** `review.spelling` checks a small built-in list of frequent misspellings
@@ -197,8 +198,8 @@ Detail in [ui-parity.md](ui-parity.md).
   blocker.**
 - **Format Shape pane thinner than PowerPoint's** (Fill/Line/Effects/Size/Text Box pages, picture
   and texture options, 3-D). 6–10 h. **Beta blocker.**
-- **First-run and start screen** (#17, #76: missing File overlay, broken layout; recent files and
-  templates thin). 3–5 h.
+- **File tab depth** (#76 landed the Backstage): no online templates, cloud places, printer
+  choice, video/GIF/CD exports or document protection. 4–8 h for the parts that need no cloud.
 - **Window chrome** (#71 macOS controls misaligned, #26 GNOME title bar, #41 system light/dark).
   2–4 h.
 - **Icon consistency across Craft apps** (#73, #56). 2–4 h; coordinate in craftrules.
@@ -255,6 +256,7 @@ Detail in [localization-parity.md](localization-parity.md).
 
 | Date | Change | Summary |
 |---|---|---|
+| 2026-10-13 | minor | Shape, picture and table rendering checked against PowerPoint on ~150 synthetic edge-case slides; 3-D bevels, cameras and face lighting now render approximately (gap narrowed to extrusion, rigs and the 3-D pane) |
 | 2026-10-12 | minor | IME composition in slide text and notes, and CJK interface text with real glyphs (#101): the IME gap is now Korean on the web and table-cell underlines |
 | 2026-10-12 | minor | EMF/WMF text, pattern and hatch brushes drawn; legacy OLE and ActiveX previews shown; the SVG gap keeps only EMF clip regions |
 | 2026-10-12 | minor | Text warps render (all 40 presets, adjusts round-trip); the warp gap is now the gallery, command and handles |

docs/parity-checklist.md

@@ -7,19 +7,19 @@ The summary between `<!-- SUMMARY -->
 
 | Priority | Features | Done | Partial | Missing | Parity |
 |---|---|---|---|---|---|
-| P0 | 72 | 60 | 12 | 0 | 92% |
+| P0 | 72 | 61 | 11 | 0 | 92% |
 | P1 | 65 | 38 | 21 | 6 | 75% |
-| P2 | 54 | 13 | 14 | 27 | 37% |
+| P2 | 54 | 13 | 15 | 26 | 38% |
 
 | Area | Parity |
 |---|---|
-| Application shell | 71% |
+| Application shell | 77% |
 | Files | 71% |
 | Slides | 90% |
 | Views | 90% |
 | Masters & themes | 85% |
 | Shapes | 88% |
-| Format | 81% |
+| Format | 83% |
 | Arrange | 100% |
 | Text | 80% |
 | Tables | 89% |
@@ -36,13 +36,13 @@ The summary between `<!-- SUMMARY -->
 | Automation (✱) | 100% |
 | Platforms (✱) | 67% |
 
-Open P0 items: Start screen (new, templates/themes, recent), Contextual tabs (Shape Format, Picture Format, Table Design/Layout, Chart Design), Export to PDF (slides, notes pages, handouts; text layer, links, bookmarks; vector artwork pending), Format Shape pane, Font, size, bold, italic, underline, strikethrough (only Regular/Bold/Italic faces, #69), Edit chart data, Crop (and crop to shape, aspect ratio), Paste image from clipboard (fails on Windows and Linux, #53), Audio/video playback in the show (WMA/WMV not decodable yet), Animation pane (reorder, timing), Presenter view (notes, next slide, timer), macOS, Windows, Linux builds.
+Open P0 items: Contextual tabs (Shape Format, Picture Format, Table Design/Layout, Chart Design), Export to PDF (slides, notes pages, handouts; text layer, links, bookmarks; vector artwork pending), Format Shape pane, Font, size, bold, italic, underline, strikethrough (only Regular/Bold/Italic faces, #69), Edit chart data, Crop (and crop to shape, aspect ratio), Paste image from clipboard (fails on Windows and Linux, #53), Audio/video playback in the show (WMA/WMV not decodable yet), Animation pane (reorder, timing), Presenter view (notes, next slide, timer), macOS, Windows, Linux builds.
 
 ## Rows
 
 | Area | Feature | Priority | Status |
 |---|---|---|---|
-| Application shell | Start screen (new, templates/themes, recent) | P0 | P |
+| Application shell | Start screen (new, templates/themes, recent) | P0 | D |
 | Application shell | Ribbon with Home/Insert/Draw/Design/Transitions/Animations/Slide Show/Review/View tabs | P0 | D |
 | Application shell | Contextual tabs (Shape Format, Picture Format, Table Design/Layout, Chart Design) | P0 | P |
 | Application shell | Quick Access toolbar / title bar commands | P1 | P |
@@ -126,7 +126,7 @@ Open P0 items: Start screen (new, templates/themes, recent), Contextual tabs (Sh
 | Format | Arrowheads | P0 | D |
 | Format | Shadow (outer, inner, presets) | P1 | D |
 | Format | Reflection, glow, soft edges | P2 | P |
-| Format | Bevel and 3-D rotation | P2 | M |
+| Format | Bevel and 3-D rotation | P2 | P |
 | Format | Format Painter | P1 | D |
 | Format | Format Shape pane | P0 | P |
 | Arrange | Size and position (exact), lock aspect ratio | P0 | D |

docs/ui-parity.md

@@ -1,6 +1,6 @@
 # UI parity with PowerPoint
 
-> **Last reviewed:** 2026-10-10 · **Last updated:** 2026-10-12 · **Change:** minor (off-slide objects in Normal view, #270) · **Target:** Microsoft PowerPoint for Mac 16.113 (Microsoft 365)
+> **Last reviewed:** 2026-10-10 · **Last updated:** 2026-10-12 · **Change:** minor (File tab / Backstage, #76; previous: off-slide objects in Normal view, #270) · **Target:** Microsoft PowerPoint for Mac 16.113 (Microsoft 365)
 
 > **Last reviewed:** 2026-10-12 · **Last updated:** 2026-10-12 · **Change:** minor (text editing keys observed in PowerPoint for Windows, #268) · **Target:** Microsoft PowerPoint for Mac 16.113 (Microsoft 365)
 
@@ -18,13 +18,42 @@ AGENTS.md §2). Dimension score: **~60% ready** (estimated), **30–50 h** to pa
 | Menu-bar items with a DeckCraft equivalent | 217 app-specific items | 128 matched by name (59%, heuristic lower bound) | See [target-app-parity.md](target-app-parity.md) |
 | Ribbon tabs: Home, Insert, Draw, Design, Transitions, Animations, Slide Show, Record, Review, View | 10 | 10 | Record tab is a placeholder |
 | Contextual tabs: Shape Format, Picture Format, Table Design, Table Layout, Chart Design, Chart Format, Video/Audio Format and Playback | yes | most; checklist P0 row partial | Chart Format, media tabs thinner |
-| Start screen: new, themes, templates, recent, open | yes | yes, thin (#17 broken layout, #76 missing overlay) | 3–5 h |
+| File tab (Backstage): Home, New, Open, Info, Save, Save As, Print, Share, Export, Close, Account, Options | yes | yes (#76), see [File tab](#file-tab-backstage); no Share (cloud) | Video/GIF/CD exports, templates beyond the built-in themes |
+| Start screen: new, themes, templates, recent, open | yes, the same page as File › Home | yes: File › Home with Home, New, Open, Account and Options (#76) | |
 | Status bar: slide counter, language, notes, comments, views, zoom slider | yes | yes | |
 | Command search (Tell Me) | yes | command palette | #79 default entry fails |
 | Light / dark appearance | follows the system | light or dark; doesn't follow the system (#41) | 1–2 h |
 | One window per presentation, New Window, Arrange All | yes | tabs in one window; no New Window | 3–5 h |
 | Quick Access Toolbar customization | yes | no | P1 partial |
 
+## File tab (Backstage)
+
+Observed black-box in PowerPoint for Windows (Microsoft 365, Version 2609, October 2026) on a
+synthetic presentation. Clicking **File** (or Alt+F) replaces the ribbon, slides and status bar with
+a full-window view; the title bar stays. A side menu 160 points wide, a step darker than the page,
+lists Back (a circled arrow), Home, New, Open, Share, a rule, Info, Save, Save As, Print, Export,
+Close and, at the bottom under a rule, Account and Options. Entries are 40 points tall with an
+outline icon; the current page is drawn in the accent colour and outlined. Esc goes back. Alt+F opens
+on Home with the keyboard in the side menu; Up and Down move through it and a page shows as soon as
+its entry has the focus. PowerPoint's start screen is the same Home page, with only Home, New and
+Open at the top. DeckCraft follows all of this (`crates/ui-egui/src/backstage.rs`), with the page and
+menu colours taken from the theme tokens (menu `chrome`, page `card`).
+
+| Page | PowerPoint | DeckCraft |
+|---|---|---|
+| Home | Prompt box (Copilot), New row of themes with More themes, Recent / Favorites / Shared with Me with a file search, More presentations | DeckCraft's mark, Blank Presentation and the first themes with More themes →, Recent with a file search and More presentations → (to Open). No Copilot prompt, Favorites or Shared with Me |
+| New | Blank Presentation, template search with suggested searches, gallery of online templates and themes | Blank Presentation, search box, the built-in themes and the sample deck (`file.new {theme}`). No online templates |
+| Open | Recent, Shared with Me, OneDrive, This PC, Add a Place, Browse; Presentations / Folders; Recover Unsaved Presentations | Recent and Browse (`app.openDialog`), recent presentations with a search box (`file.open`), Recover Unsaved Presentations (`file.recovery.open`). No cloud places or Folders tab |
+| Info | Name and path, Upload / Share / Copy path / Open file location; Protect, Inspect, Version History, Manage Presentation; Properties, Related Dates, Related People | Name and path, Copy path, Open file location; Inspect Presentation (Accessibility Checker), Manage Presentation (Revert); Size, Slides, Hidden slides and editable Title, Subject, Tags, Categories, Company, Comments, Author (`file.info`, `file.properties`). No Protect, Version History or dates |
+| Save | Saves; a presentation never saved goes to Save As | Same (`file.save`) |
+| Save As | Places, folder, file name, type, Save, More options | Type (PowerPoint, DeckCraft, PDF, Outline, PNG, JPEG) and Save, which opens the system Save dialog (web: Download). .pptx/.deckcraft take the new file; the others are copies (`file.saveAs`, `file.export`) |
+| Print | Print and Copies, Printer, Print All / Selection / Current / Custom Range, Slides box, layout (Full Page Slides, Notes Pages, Outline, Handouts 1–9), sides, collation, colour, Edit Header & Footer; page preview with pager and zoom | Print, Print All Slides / Current Slide / Custom Range, Slides box (`1-3, 5`), Full Page Slides / Notes Pages / Handouts 1–9, Print Hidden Slides, Frame Slides, Edit Header & Footer; preview with pager. DeckCraft prints through a PDF (`file.export`) opened in the system viewer, which has the printers (web: downloaded). No printer list, copies, sides or colour |
+| Share | Cloud sharing | Not offered |
+| Export | Create PDF/XPS Document, Create a Video, Create an Animated GIF, Package Presentation for CD, Create Handouts, Change File Type | Create PDF Document, Create Handouts (a PDF), Change File Type. No video, GIF or CD package |
+| Close | Closes; asks Save / Don't Save / Cancel about unsaved changes | Same (`file.close` after the prompt); Ctrl+W asks too |
+| Account | User information, sign-in, Office Background and Office Theme, product information, About | Appearance (light/dark, `view.dark`), product information, About DeckCraft. No accounts to sign in to |
+| Options | Opens the PowerPoint Options dialog | Opens Preferences |
+
 ## Panes and dialogs
 
 | Pane / dialog | PowerPoint | DeckCraft |
@@ -109,7 +138,7 @@ imitate Microsoft's. No pixel comparison against PowerPoint screenshots has been
 | Native macOS menu bar from `menu_tree()`, filled out to PowerPoint's menu items | 3–5 |
 | Format Shape pane depth | 6–10 |
 | Missing dialogs (Font, Bullets and Numbering, Find/Replace, Replace Fonts, Action Settings, Print, Insert Object) | 8–14 |
-| Start screen, window chrome, system appearance, palette fixes (#17, #41, #71, #76, #79) | 4–7 |
+| Window chrome, system appearance, palette fixes (#41, #71, #79) | 3–5 |
 | Grid Options, edit points UI, crop depth | 4–7 |
 | Multiple windows | 3–5 |
 | A screenshot comparison pass on the most-used tabs | 2–4 |
@@ -119,6 +148,7 @@ imitate Microsoft's. No pixel comparison against PowerPoint screenshots has been
 
 | Date | Change | Summary |
 |---|---|---|
+| 2026-10-12 | minor | File tab (Backstage) observed in PowerPoint for Windows and matched (#76); the start screen is File › Home |
 | 2026-10-12 | minor | Off-slide objects drawn and editable around the slide in Normal view (#270) |
 | 2026-10-12 | minor | Selection Pane matched to PowerPoint (#133): drag and drop, arrows, groups, eye, Lock |
 | 2026-10-12 | minor | Text editing keys: Ctrl+arrows, Ctrl+Backspace/Delete, Ctrl+Up/Down, Home/End on wrapped lines, Shift+F3, font size keys, as observed in PowerPoint for Windows (#268) |