Merge pull request #1864 from storytold/fix/audit-render-effects

Fix #1706, #1705, #1724, #1723, #1683: shadow raster budget, Transform copies, 3D fill rule, pattern tiles, template Dim Images

crates/effects/src/distort.rs

@@ -108,6 +108,10 @@ const MAX_SCALE: f64 = 100_000.0;
 const MAX_MOVE: f64 = 1.0e7;
 /// The Transform effect's copies stop before one reaches further than this (pt) from the origin.
 const MAX_REACH: f64 = 1.0e9;
+/// Most anchors a Transform effect's copies make of a path, the original included: 1000 copies of
+/// a 2000-anchor path. Stacked Transform effects multiply their copies (three of 1000 copies make
+/// a thousand million of one square), so the limit is on the result, not on each effect's count.
+pub(crate) const MAX_COPY_ANCHORS: usize = 2_000_000;
 
 /// Transform effect: scale, rotate and reflect about reference point `reference` of the bounds
 /// (the 9-point grid, 4 = centre), then move; `copies` more times, each from the last. With
@@ -115,6 +119,11 @@ const MAX_REACH: f64 = 1.0e9;
 /// the angle a share of theirs, drawn from `seed` (the object's), so an object keeps its result
 /// on every redraw while each object varies its own way.
 pub fn transform(path: &PathData, b: Rect, p: &Value, seed: u64) -> PathData {
+    transform_within(path, b, p, seed, MAX_COPY_ANCHORS)
+}
+
+/// [`transform`] whose copies make at most `max` anchors of the path, the original included.
+pub(crate) fn transform_within(path: &PathData, b: Rect, p: &Value, seed: u64, max: usize) -> PathData {
     let random = flag(p, "random", false);
     // The share (0..1) of value `k` applied.
     let share = |k: u64| if random { (noise(seed, k, 0, 0) + 1.0) / 2.0 } else { 1.0 };
@@ -132,9 +141,17 @@ pub fn transform(path: &PathData, b: Rect, p: &Value, seed: u64) -> PathData {
         return path.transformed(m);
     }
     let within = |r: Rect| [r.x0, r.y0, r.x1, r.y1].iter().all(|v| v.abs() <= MAX_REACH);
+    // Each copy adds the path once more, and a Transform after this one copies the lot again:
+    // copies stop where the result would pass [`MAX_COPY_ANCHORS`] (#1705).
+    let each = path.anchor_count();
+    let mut anchors = each;
     let mut out = path.clone();
     let mut cur = path.clone();
     for _ in 0..copies {
+        anchors = anchors.saturating_add(each);
+        if anchors > max {
+            break;
+        }
         cur = cur.transformed(m);
         if !cur.bounds().is_some_and(within) {
             break;

crates/effects/src/solids.rs

@@ -113,19 +113,19 @@ fn profile(n: &Node) -> Option<(PathData, FillRule)> {
     }
 }
 
-fn facets(id: &str, path: &PathData, bounds: Rect, p: &Value) -> Result<Vec<Facet>, String> {
+fn facets(id: &str, path: &PathData, rule: FillRule, bounds: Rect, p: &Value) -> Result<Vec<Facet>, String> {
     let view = view_options(p);
     match id {
-        EXTRUDE => vectorcraft_three_d::extrude(path, bounds, extrude_options(p), view),
+        EXTRUDE => vectorcraft_three_d::extrude(path, rule, bounds, extrude_options(p), view),
-        INFLATE => vectorcraft_three_d::inflate(path, bounds, inflate_options(p), view),
+        INFLATE => vectorcraft_three_d::inflate(path, rule, bounds, inflate_options(p), view),
-        _ => vectorcraft_three_d::plane(path, bounds, view),
+        _ => vectorcraft_three_d::plane(path, rule, bounds, view),
     }
 }
 
 /// Validate before a command changes the document; the evaluator bounds loaded files too.
 pub fn validate_solid(n: &Node, id: &str, p: &Value) -> Result<(), String> {
     let label = crate::effect_info(id).map_or("This effect", |e| e.label.trim_end_matches('…'));
-    let (path, _) =
+    let (path, rule) =
         profile(n).ok_or_else(|| format!("{label} currently requires a path or compound path. Convert type, images and groups to paths first."))?;
     let b = path.bounds().ok_or_else(|| format!("{label} requires a shape with at least two anchors"))?;
     if let Some(v) = p.get("bevel")
@@ -134,7 +134,7 @@ pub fn validate_solid(n: &Node, id: &str, p: &Value) -> Result<(), String> {
         let names: Vec<_> = BevelShape::ALL.iter().map(|b| b.id()).collect();
         return Err(format!("bevel must be none or one of {}", names.join(", ")));
     }
-    facets(id, &path, b, p).map(|_| ())
+    facets(id, &path, rule, b, p).map(|_| ())
 }
 
 /// One surface: each facet a path shaded from `paint`, as a group with the paint's opacity and
@@ -185,11 +185,12 @@ fn paint_of(item: &AppearanceItem) -> (Paint, f32, BlendMode) {
     }
 }
 
-/// The area `item` paints on `path`: the path itself for a fill, the stroke's outline for a stroke.
+/// The area `item` paints on `path`, and the rule that fills it: the path itself for a fill, the
-fn region(path: &PathData, rule: FillRule, item: &AppearanceItem) -> PathData {
+/// stroke's outline (whose contours nest as its holes do) for a stroke.
+fn region(path: &PathData, rule: FillRule, item: &AppearanceItem) -> (PathData, FillRule) {
     match item {
-        AppearanceItem::Stroke(s) if s.width > 0.0 && s.width.is_finite() => crate::stroke::outline_region(path, rule, s),
+        AppearanceItem::Stroke(s) if s.width > 0.0 && s.width.is_finite() => (crate::stroke::outline_region(path, rule, s), FillRule::EvenOdd),
-        _ => path.clone(),
+        _ => (path.clone(), rule),
     }
 }
 
@@ -204,7 +205,8 @@ fn art_for(n: &Node, fx: &Effect, path: &PathData, rule: FillRule, items: &[&App
         let mut out = vec![];
         for item in items {
             let (paint, opacity, blend) = paint_of(item);
-            let f = facets(ROTATE, &region(path, rule, item), b, &p).ok()?;
+            let (area, rule) = region(path, rule, item);
+            let f = facets(ROTATE, &area, rule, b, &p).ok()?;
             out.push(Arc::new(surface(n, f, &paint, opacity, blend)));
         }
         return Some(out);
@@ -213,7 +215,7 @@ fn art_for(n: &Node, fx: &Effect, path: &PathData, rule: FillRule, items: &[&App
     let (paint, opacity, blend) = paint_of(item);
     // A loaded file or a shape edited past the limits keeps drawing its source path instead of
     // failing the frame; commands validate the same evaluator and report its errors.
-    let f = facets(&fx.id, path, b, &p).ok()?;
+    let f = facets(&fx.id, path, rule, b, &p).ok()?;
     Some(vec![Arc::new(surface(n, f, &paint, opacity, blend))])
 }
 

crates/effects/src/tests.rs

@@ -206,6 +206,24 @@ fn random_transform_is_stable_per_object_and_within_the_values() {
     assert!(close(r.width(), 50.0, 1e-9) && close(r.center().x, 90.0, 1e-9), "{r:?}");
 }
 
+/// #1705: stacked Transform effects multiply their copies; the anchors they make are bounded,
+/// whatever each one's count.
+#[test]
+fn stacked_transform_copies_stay_within_the_anchor_budget() {
+    let p = json!({"copies": 1000});
+    let b = square().bounds().unwrap();
+    let mut path = square();
+    let mut counts = vec![];
+    for _ in 0..3 {
+        path = crate::distort::transform_within(&path, b, &p, 0, 100);
+        counts.push(path.anchor_count());
+    }
+    assert_eq!(counts, [100, 100, 100], "25 squares, then no room for a copy of them");
+    // Within the budget every copy is made, and the effect's own budget takes a thousand copies.
+    assert_eq!(crate::distort::transform_within(&square(), b, &json!({"copies": 24}), 0, 100).subpaths.len(), 25);
+    assert_eq!(run("distort.transform", p, &square()).subpaths.len(), 1001);
+}
+
 #[test]
 fn transform_copies_stop_before_they_overflow() {
     let out = run("distort.transform", json!({"scaleH": 100000, "scaleV": 100000, "copies": 1000}), &square());

crates/render/src/fx.rs

@@ -366,6 +366,29 @@ fn linear_key(view: Affine) -> [u64; 4] {
     [c[0].to_bits(), c[1].to_bits(), c[2].to_bits(), c[3].to_bits()]
 }
 
+/// The raster a shadow or glow blurred by `blur` device pixels is filtered in, for content
+/// reaching `reach` (device pixels) in a view of `screen` pixels: (left, top, width, height,
+/// scale). It covers what of the reach can show in the view, the blur's spread around it
+/// included, at `scale` raster pixels a device pixel: 1, or less to stay within
+/// [`PIXEL_BUDGET`]. At a high zoom the spread of a wide blur is tens of thousands of pixels a
+/// side, whatever the size of the view (#1706). `None`: nothing to draw.
+fn filter_region(reach: Rect, screen: (u16, u16), blur: f64) -> Option<(f64, f64, u16, u16, f64)> {
+    // 3σ of the Gaussian (σ = blur / 2) in pixels, plus a pixel of antialiasing.
+    let spread = blur.max(0.0) * 1.5 + 2.0;
+    let screen = Rect::new(0.0, 0.0, f64::from(screen.0), f64::from(screen.1)).inflate(spread, spread);
+    let r = reach.inflate(spread, spread).intersect(screen);
+    let (x0, y0) = (r.x0.floor(), r.y0.floor());
+    let (rw, rh) = (r.x1.ceil() - x0, r.y1.ceil() - y0);
+    // (Also false for a reach or a blur that isn't a number.)
+    if !(rw >= 1.0 && rh >= 1.0 && rw.is_finite() && rh.is_finite()) {
+        return None;
+    }
+    let side = f64::from(u16::MAX);
+    let k = (PIXEL_BUDGET / (rw * rh)).sqrt().min(side / rw).min(side / rh).min(1.0);
+    let (w, h) = ((rw * k).floor().clamp(1.0, side), (rh * k).floor().clamp(1.0, side));
+    Some((x0, y0, w as u16, h as u16, k))
+}
+
 /// Draw `image` with its top-left at (`x`, `y`) device pixels, `1 / k` device pixels a pixel.
 fn draw_scaled(ctx: &mut RenderContext, image: std::sync::Arc<vello_cpu::Pixmap>, (x, y): (f64, f64), k: f64) {
     let (w, h) = (image.width() as f64, image.height() as f64);
@@ -509,7 +532,8 @@ impl Drawn {
 /// objects in it ([`Reads::of`]): which parts of [`Inputs`] can change what its rasters show.
 #[derive(Clone, Copy, Debug, Default, PartialEq, Eq)]
 pub(crate) struct Reads {
-    /// Pattern paints: the pattern definitions.
+    /// Pattern paints: the pattern definitions. Their art can hold anything, so content painted
+    /// with a pattern reads everything else too.
     patterns: bool,
     /// Symbol instances and type with inline graphics: the symbols' art. Symbol art can hold
     /// anything, so content that shows a symbol reads everything else too.
@@ -527,14 +551,25 @@ pub(crate) struct Reads {
 impl Reads {
     /// What the content of `n` reads.
     pub(crate) fn of(n: &Node) -> Self {
+        Self::of_all(std::iter::once(n))
+    }
+
+    /// What the content of `nodes` reads together. A pattern's art can hold anything, as a
+    /// symbol's can, so content painted with a pattern reads everything else too (#1723).
+    pub(crate) fn of_all<'a>(nodes: impl Iterator<Item = &'a Node>) -> Self {
         let mut reads = Self::default();
-        reads.add(n);
+        nodes.for_each(|n| reads.add(n));
-        if reads.symbols {
+        if reads.symbols || reads.patterns {
             return Self { patterns: true, symbols: true, images: true, brushes: true, text: true };
         }
         reads
     }
 
+    /// Does the content read anything outside its own nodes?
+    pub(crate) fn any(self) -> bool {
+        self != Self::default()
+    }
+
     fn add(&mut self, n: &Node) {
         let pattern = |p: &vectorcraft_color::Paint| matches!(p, vectorcraft_color::Paint::Pattern { .. });
         n.walk(&mut |c| {
@@ -1365,18 +1400,9 @@ impl Renderer {
         if !f.mt {
             return self.inside_layer(|r| draw(r, ctx, f, composite));
         }
-        // 3σ of the Gaussian (σ = blur / 2) in pixels, plus a pixel of antialiasing.
+        let Some((x0, y0, w, h, k)) = filter_region(f.view.transform_rect_bbox(reach), (ctx.width(), ctx.height()), blur / f.px) else { return };
-        let spread = blur.max(0.0) * 1.5 / f.px + 2.0;
-        let screen = Rect::new(0.0, 0.0, ctx.width() as f64, ctx.height() as f64).inflate(spread, spread);
-        let r = f.view.transform_rect_bbox(reach).inflate(spread, spread).intersect(screen);
-        let (x0, y0) = (r.x0.floor(), r.y0.floor());
-        let (w, h) = ((r.x1.ceil() - x0).min(u16::MAX as f64), (r.y1.ceil() - y0).min(u16::MAX as f64));
-        if w < 1.0 || h < 1.0 {
-            return;
-        }
-        let (w, h) = (w as u16, h as u16);
         let mut off = f.offscreen_context(w, h);
-        let shifted = Frame { mt: false, view: Affine::translate((-x0, -y0)) * f.view, ..*f };
+        let shifted = Frame { mt: false, view: Affine::scale(k) * Affine::translate((-x0, -y0)) * f.view, px: f.px / k, ..*f };
         self.inside_layer(|r| draw(r, &mut off, &shifted, None));
         off.flush();
         let mut pm = vello_cpu::Pixmap::new(w, h);
@@ -1386,7 +1412,12 @@ impl Renderer {
             ctx.set_transform(Affine::IDENTITY);
             ctx.push_layer(None, Some(blend_mode(m)), Some(o), None, None);
         }
-        crate::group::draw_pixmap(ctx, std::sync::Arc::new(pm), (x0, y0));
+        if k < 1.0 {
+            draw_scaled(ctx, std::sync::Arc::new(pm), (x0, y0), k);
+            ctx.set_transform(Affine::IDENTITY);
+        } else {
+            crate::group::draw_pixmap(ctx, std::sync::Arc::new(pm), (x0, y0));
+        }
         if layered {
             ctx.pop_layer();
         }
@@ -1482,9 +1513,28 @@ mod tests {
     use vectorcraft_doc::{Appearance, Document, Effect, Node};
     use vectorcraft_geom::{Affine, Rect, shapes};
 
-    use super::Drawn;
+    use super::{Drawn, PIXEL_BUDGET, filter_region};
     use crate::{RenderOptions, Rendered, Renderer};
 
+    /// #1706: the raster a shadow or glow is filtered in stays within the pixel budget however
+    /// far the blur spreads at the zoom (it was up to 65535 pixels a side: 16 GB).
+    #[test]
+    fn a_wide_blur_at_a_high_zoom_is_filtered_within_the_pixel_budget() {
+        // A 100 pt square at 3200 % and at 6400 %, blurred by 1000 pt, in a 1600 × 1000 view.
+        for zoom in [32.0, 64.0] {
+            let reach = Rect::new(0.0, 0.0, 100.0 * zoom, 100.0 * zoom);
+            let (x0, y0, w, h, k) = filter_region(reach, (1600, 1000), 1000.0 * zoom).unwrap();
+            assert!(f64::from(w) * f64::from(h) <= PIXEL_BUDGET, "{w} × {h}");
+            assert!(k < 1.0 && x0 < 0.0 && y0 < 0.0);
+            // It still covers the view and the blur's spread around it, at that scale.
+            assert!(f64::from(w) / k >= 1600.0 + 1500.0 * zoom && f64::from(h) / k >= 1000.0 + 1500.0 * zoom);
+        }
+        // A small blur is filtered at full size, cropped to what can show.
+        assert_eq!(filter_region(Rect::new(10.0, 20.0, 110.0, 70.0), (1600, 1000), 4.0), Some((2.0, 12.0, 116, 66, 1.0)));
+        assert_eq!(filter_region(Rect::new(5000.0, 0.0, 5100.0, 100.0), (1600, 1000), 4.0), None, "off the view");
+        assert_eq!(filter_region(Rect::new(0.0, 0.0, 100.0, 100.0), (1600, 1000), f64::NAN).map(|r| r.4), Some(1.0));
+    }
+
     fn doc_with(r: Rect, fill: Color, effects: Vec<(&str, serde_json::Value)>) -> Document {
         let mut d = Document::new(100.0, 100.0);
         let id = d.alloc_id();

crates/render/src/lib.rs

@@ -83,7 +83,8 @@ pub struct RenderOptions {
     pub artboards: bool,
     /// Objects not to draw (e.g. the object being edited by a live drag preview).
     pub hidden: Vec<NodeId>,
-    /// Draw template layers dimmed (50%).
+    /// Draw the layers as their Layer Options show them on screen: Preview off in outline, Dim
+    /// Images fading their images (a template layer's too), a template in Preview in Outline view.
     pub dim_templates: bool,
     /// Soft proof / separations preview (see [`proof`]).
     pub proof: Option<proof::ProofSetup>,
@@ -1088,8 +1089,8 @@ impl Renderer {
             return;
         }
         // Layer Options on screen: a layer whose Preview is off draws in outline, and Dim Images
-        // fades its images (exports and thumbnails, which leave templates out, ignore both).
+        // fades its images, a template's too (exports and thumbnails, which leave templates out,
-        // (A template is dimmed as a whole already.)
+        // ignore both).
         if let NodeKind::Layer { preview, dim_images, template, .. } = &n.kind
             && f.opts.dim_templates
             && !f.opts.skip_templates
@@ -1104,7 +1105,7 @@ impl Renderer {
                 let opts = RenderOptions { outline: true, ..f.opts.clone() };
                 return self.draw_node(ctx, &Frame { opts: &opts, ..*f }, n, force);
             }
-            if let Some(p) = dim_images.filter(|_| !template) {
+            if let Some(p) = *dim_images {
                 let outer = self.dim_images;
                 let dim = f32::from(p).clamp(0.0, 100.0) / 100.0;
                 self.dim_images = Some(outer.map_or(dim, |o| o.min(dim)));
@@ -1162,8 +1163,7 @@ impl Renderer {
             return self.draw_object_fx(ctx, f, &Arc::new(n.clone()), false);
         }
         let outline = f.opts.outline;
-        let template_dim = matches!(n.kind, NodeKind::Layer { template: true, .. }) && f.opts.dim_templates;
+        let opacity = self.opacity_of(n);
-        let opacity = if template_dim { self.opacity_of(n) * 0.5 } else { self.opacity_of(n) };
         // Whether this container's children knock each other out.
         let knockout = !outline && n.knocks_out(self.knockout);
         let enclosing = std::mem::replace(&mut self.knockout, knockout);

crates/render/src/pattern.rs

@@ -6,14 +6,16 @@
 //! with the paint transform mapping pixels → pattern space → document. Tiles are cached per
 //! pattern name and raster scale (and ink plane, see [`crate::ink`]) within
 //! [`lru::PATTERN_BUDGET`]. A tile is used while the pattern's definition is the one it was
-//! rasterized from (art `Arc` identity, tile, tile type, overlap): the pattern's "revision".
+//! rasterized from (art `Arc` identity, tile, tile type, overlap): the pattern's "revision", and,
+//! when its art shows more than itself (a symbol, another pattern, an image, type), while what
+//! the document holds of those is what it held then ([`Deps`]).
 //!
 //! Pattern editing mode (`Document::pattern_edit`) draws only the temporary tile layer, with
 //! dimmed copies of it at the neighbouring tile positions and the tile edge.
 
 use std::cell::RefCell;
 use std::hash::{Hash, Hasher};
-use std::sync::Arc;
+use std::sync::{Arc, Weak};
 
 use vectorcraft_doc::pattern::{Overlap, PatternDef, TileType};
 use vectorcraft_doc::{Document, Node};
@@ -32,8 +34,46 @@ const MAX_TILE_PX: f64 = 2048.0;
 /// ([`raster_scale`]).
 type TileKey = (String, u64);
 
+/// What a tile was drawn from besides its pattern's own art, for art that shows more than itself:
+/// the art of every pattern and symbol and the pixels of every image in the document, and the
+/// fonts. Editing a symbol leaves the art of a pattern that shows it as it was, so the art alone
+/// kept the tile from before (#1723). Held weakly: a weak reference keeps the allocation, so no
+/// other value gets one of these addresses while the tile is kept.
+struct Deps {
+    art: Vec<Weak<Node>>,
+    pixels: Vec<Weak<Vec<u8>>>,
+    fonts: u64,
+}
+
+impl Deps {
+    fn art(doc: &Document) -> impl Iterator<Item = &Arc<Node>> {
+        doc.patterns.iter().flat_map(|p| &p.art).chain(doc.symbols.iter().map(|s| &s.art))
+    }
+
+    fn pixels(doc: &Document) -> impl Iterator<Item = &Arc<Vec<u8>>> {
+        doc.images.values().flat_map(|b| std::iter::once(&b.bytes).chain(&b.proxy))
+    }
+
+    fn of(doc: &Document) -> Self {
+        Self {
+            art: Self::art(doc).map(Arc::downgrade).collect(),
+            pixels: Self::pixels(doc).map(Arc::downgrade).collect(),
+            fonts: vectorcraft_text::FontDb::global().generation(),
+        }
+    }
+
+    /// Does `doc` hold what the tile was drawn from?
+    fn current(&self, doc: &Document) -> bool {
+        self.fonts == vectorcraft_text::FontDb::global().generation()
+            && self.art.iter().map(Weak::as_ptr).eq(Self::art(doc).map(Arc::as_ptr))
+            && self.pixels.iter().map(Weak::as_ptr).eq(Self::pixels(doc).map(Arc::as_ptr))
+    }
+}
+
 struct TileEntry {
     art: Vec<Arc<Node>>,
+    /// `None` for art that shows only itself.
+    deps: Option<Deps>,
     params: (Rect, TileType, Overlap),
     sx: f64,
     sy: f64,
@@ -163,7 +203,10 @@ pub(crate) fn set_pattern_paint(ctx: &mut RenderContext, name: &str, xf: Affine,
         let mut c = c.borrow_mut();
         let tiles = &mut c.tiles[ink as usize];
         let t = tiles.tick();
-        tiles.get(&key, t).filter(|e| e.params == params && same_art(&e.art, &def.art)).map(|e| (e.pixmap.clone(), e.sx, e.sy))
+        tiles
+            .get(&key, t)
+            .filter(|e| e.params == params && same_art(&e.art, &def.art) && e.deps.as_ref().is_none_or(|d| d.current(doc)))
+            .map(|e| (e.pixmap.clone(), e.sx, e.sy))
     });
     let (pm, sx, sy) = match hit {
         Some(h) => h,
@@ -176,11 +219,12 @@ pub(crate) fn set_pattern_paint(ctx: &mut RenderContext, name: &str, xf: Affine,
             };
             let pm = Arc::new(pm);
             let (sx, sy) = (w as f64 / pw, h as f64 / ph);
+            let deps = crate::fx::Reads::of_all(def.art.iter().map(|a| &**a)).any().then(|| Deps::of(doc));
             CACHE.with(|c| {
                 let mut c = c.borrow_mut();
                 let tiles = &mut c.tiles[ink as usize];
                 let (t, bytes) = (tiles.tick(), size_of::<TileEntry>() + w as usize * h as usize * 4);
-                tiles.insert(key, TileEntry { art: def.art.clone(), params, sx, sy, pixmap: pm.clone() }, bytes, t);
+                tiles.insert(key, TileEntry { art: def.art.clone(), deps, params, sx, sy, pixmap: pm.clone() }, bytes, t);
             });
             (pm, sx, sy)
         }

crates/render/src/tests_layeropts.rs

@@ -67,13 +67,37 @@ fn dim_images_fades_only_the_images() {
     assert_eq!(render(&d, true).pixel(65, 25), [255, 0, 0, 255], "exports are not dimmed");
 }
 
+/// #1683: a template layer dims its images by its Dim Images percentage and nothing else: with
+/// the option off they show at full strength, and the layer's paths are never faded.
+#[test]
+fn a_template_layer_dims_its_images_by_dim_images() {
+    let template = |dim: Option<u8>| {
+        let d = doc(|k| {
+            if let NodeKind::Layer { template, dim_images, .. } = k {
+                (*template, *dim_images) = (true, dim);
+            }
+        });
+        let img = render(&d, false);
+        (img.pixel(65, 25), img.pixel(25, 25))
+    };
+    let red = [255, 0, 0, 255];
+    assert_eq!(template(None), (red, red), "Dim Images off: as it is");
+    let (image, path) = template(Some(50));
+    assert!(image[0] == 255 && (120..=135).contains(&image[1]) && image[1] == image[2], "half way to white: {image:?}");
+    assert_eq!(path, red, "vector art stays");
+    let (image, _) = template(Some(20));
+    assert!((198..=210).contains(&image[1]) && image[1] == image[2], "a fifth of its strength: {image:?}");
+    assert_eq!(template(Some(100)), (red, red));
+}
+
 /// In Outline view a template layer still draws in Preview, dimmed, so its picture can be traced;
 /// the layer above it draws in outline (#1486).
 #[test]
 fn a_template_layer_stays_in_preview_in_outline_view() {
     let mut d = doc(|k| {
-        if let NodeKind::Layer { template, preview, .. } = k {
+        if let NodeKind::Layer { template, preview, dim_images, .. } = k {
-            *template = true;
+            // As Layer Options makes a template: its images dimmed to 50 %.
+            (*template, *dim_images) = (true, Some(50));
             // Preview off doesn't put a template in outline either.
             *preview = false;
         }

crates/render/src/tests_memory.rs

@@ -940,6 +940,49 @@ fn rasters_draw_pattern_edits() {
     });
 }
 
+/// #1723: a pattern's tile is drawn again when what its art shows changes while the art itself
+/// doesn't: a symbol an instance in it shows, or another pattern it is painted with. So is a
+/// raster effect on an object painted with such a pattern.
+#[test]
+fn pattern_tiles_draw_edits_to_what_their_art_shows() {
+    let _fonts = fonts_steady();
+    use vectorcraft_doc::pattern::{PatternDef, pattern_paint};
+    use vectorcraft_geom::shapes::rectangle;
+    let tile = |name: &str, art: Node| {
+        let mut def = PatternDef::new(name, vec![Arc::new(art)]);
+        def.tile = Rect::new(0.0, 0.0, 20.0, 20.0);
+        def
+    };
+    // Pattern `Stamps` shows symbol `S`; pattern `Outer` is a square painted with pattern `Checks`.
+    let doc = |pattern: &str, effects: Vec<vectorcraft_doc::Effect>| {
+        let mut d = Document::new(200.0, 100.0);
+        let art = symbol_art(&mut d);
+        d.symbols.push(vectorcraft_doc::Symbol { name: "S".into(), art: Arc::new(art) });
+        let shown = Node::new(d.alloc_id(), NodeKind::SymbolInstance { symbol: "S".into(), xf: Affine::translate((10.0, 10.0)) });
+        d.patterns.push(tile("Stamps", shown));
+        d.patterns.push(checks(Color::rgb(1.0, 0.0, 0.0)));
+        let square = filled(&mut d, rectangle(Rect::new(0.0, 0.0, 20.0, 20.0)), pattern_paint("Checks"), vec![]);
+        d.patterns.push(tile("Outer", square));
+        let painted = filled(&mut d, rectangle(Rect::new(10.0, 10.0, 190.0, 90.0)), pattern_paint(pattern), effects);
+        with_art(d, vec![painted])
+    };
+    let new_symbol = |d: &mut Document| {
+        let red = vectorcraft_doc::Appearance::basic(Paint::solid(Color::rgb(1.0, 0.0, 0.0)), Paint::None, 0.0);
+        let bar = Node::path(d.alloc_id(), rectangle(Rect::new(-8.0, -2.0, 8.0, 2.0)), red);
+        d.symbols[0].art = Arc::new(bar);
+    };
+    let new_checks = |d: &mut Document| {
+        if let Some(def) = d.pattern_mut("Checks") {
+            def.art = checks(Color::rgb(0.0, 0.0, 1.0)).art;
+        }
+    };
+    let blur = || vec![effect("blur.gaussian", serde_json::json!({"radius": 2.0}))];
+    edit_draws_as_new(doc("Stamps", vec![]), new_symbol);
+    edit_draws_as_new(doc("Stamps", blur()), new_symbol);
+    edit_draws_as_new(doc("Outer", vec![]), new_checks);
+    edit_draws_as_new(doc("Outer", blur()), new_checks);
+}
+
 /// Raster effects are made again when a symbol shown inside another symbol changes (a group's drop
 /// shadow around an instance of the other symbol), when a brush definition changes (a brushed
 /// stroke's drop shadow), and when an image's pixels change under the same key, as when a linked

crates/three-d/src/solid.rs

@@ -9,7 +9,7 @@
 //! Visibility is a painter's algorithm, as for Revolve: faces of a closed solid that face away
 //! from the viewer are left out, the rest are drawn back to front.
 
-use vectorcraft_geom::{BezPath, ParamCurve, PathData, Point, Rect};
+use vectorcraft_geom::{BezPath, FillRule, ParamCurve, PathData, Point, Rect};
 
 use crate::{MAX_FACES, Revolve, V3, eye_distance, perspective_scale};
 
@@ -290,7 +290,11 @@ fn pieces(c: vectorcraft_geom::CubicBez, tolerance: f64) -> u32 {
 /// outlines run one way and holes the other, so nonzero winding fills them as the art is. Curves
 /// are followed within a tolerance of 1/2000 of `size` (at least 0.05 pt), so small curves take
 /// few points and large ones more; more than `limit` points in all is refused.
-fn rings(path: &PathData, size: f64, limit: usize) -> Result<Vec<Vec<Point>>, String> {
+///
+/// Under the nonzero `rule` an outline with filled art on both sides is no edge of the shape and
+/// is left out: a contour inside another that runs the same way doesn't cut a hole, as it would
+/// if nesting alone decided (#1724).
+fn rings(path: &PathData, rule: FillRule, size: f64, limit: usize) -> Result<Vec<Vec<Point>>, String> {
     let tolerance = (size / 2000.0).max(0.05);
     let mut count = 0;
     let mut out = vec![];
@@ -325,6 +329,18 @@ fn rings(path: &PathData, size: f64, limit: usize) -> Result<Vec<Vec<Point>>, St
             out.push(ring);
         }
     }
+    if rule == FillRule::NonZero {
+        let turn = |r: &[Point]| if signed_area(r) > 0.0 { 1 } else { -1 };
+        let mut edge = Vec::with_capacity(out.len());
+        for (i, r) in out.iter().enumerate() {
+            let p = r.first().copied().unwrap_or_default();
+            // The winding number just outside the ring, and just inside it.
+            let outside: i32 = out.iter().enumerate().filter(|(j, o)| *j != i && contains(o, p)).map(|(_, o)| turn(o)).sum();
+            edge.push((outside != 0) != (outside + turn(r) != 0));
+        }
+        let mut edge = edge.into_iter();
+        out.retain(|_| edge.next().unwrap_or(true));
+    }
     // A ring inside an odd number of others is a hole.
     let holes: Vec<bool> = out
         .iter()
@@ -634,14 +650,14 @@ fn steps(o: &Extrude) -> Vec<Step> {
 
 /// Extrude & Bevel: the shape's outline extruded backwards, with optional twist, taper, bevels
 /// and caps.
-pub fn extrude(path: &PathData, bounds: Rect, options: Extrude, view: View) -> Result<Vec<Facet>, String> {
+pub fn extrude(path: &PathData, rule: FillRule, bounds: Rect, options: Extrude, view: View) -> Result<Vec<Facet>, String> {
     check_bounds(bounds)?;
     let o = options.sanitized();
     // No depth: the flat shape, seen from either side.
     if o.depth <= 0.0 {
-        return plane(path, bounds, view);
+        return plane(path, rule, bounds, view);
     }
-    let rings = rings(path, bounds.width().max(bounds.height()), MAX_SOLID_POINTS)?;
+    let rings = rings(path, rule, bounds.width().max(bounds.height()), MAX_SOLID_POINTS)?;
     let camera = Camera::new(view, bounds, o.depth);
     let mut b = Builder { camera: &camera, closed: o.cap, facets: vec![] };
     let steps = steps(&o);
@@ -675,9 +691,9 @@ pub fn extrude(path: &PathData, bounds: Rect, options: Extrude, view: View) -> R
 
 /// Rotate: the flat art turned in 3D about the centre of `bounds` (which may be larger than the
 /// shape's own, so that every part of one object turns about the same point).
-pub fn plane(path: &PathData, bounds: Rect, view: View) -> Result<Vec<Facet>, String> {
+pub fn plane(path: &PathData, rule: FillRule, bounds: Rect, view: View) -> Result<Vec<Facet>, String> {
     check_bounds(bounds)?;
-    let rings = rings(path, bounds.width().max(bounds.height()), MAX_PLANE_POINTS)?;
+    let rings = rings(path, rule, bounds.width().max(bounds.height()), MAX_PLANE_POINTS)?;
     let camera = Camera::new(view, bounds, 0.0);
     let mut b = Builder { camera: &camera, closed: false, facets: vec![] };
     let contours: Vec<Vec<V3>> = rings.iter().map(|r| r.iter().map(|p| camera.place(*p, 0.0)).collect()).collect();
@@ -997,18 +1013,18 @@ fn material(outline: &PathData, cell: Rect) -> Option<Vec<Vec<Point>>> {
         &[Point::new(cell.x0, cell.y0), Point::new(cell.x1, cell.y0), Point::new(cell.x1, cell.y1), Point::new(cell.x0, cell.y1)],
         true,
     ));
-    let rule = vectorcraft_geom::FillRule::NonZero;
+    let rule = FillRule::NonZero;
     let part =
         vectorcraft_pathops::try_boolean(&r, rule, outline, rule, vectorcraft_pathops::BoolOp::Intersect, vectorcraft_pathops::DEFAULT_PRECISION)
             .ok()?;
-    rings(&part, cell.width(), MAX_PLANE_POINTS).ok()
+    rings(&part, rule, cell.width(), MAX_PLANE_POINTS).ok()
 }
 
 /// Inflate: the shape puffed out like a cushion, its edge kept where the art's outline is.
-pub fn inflate(path: &PathData, bounds: Rect, options: Inflate, view: View) -> Result<Vec<Facet>, String> {
+pub fn inflate(path: &PathData, rule: FillRule, bounds: Rect, options: Inflate, view: View) -> Result<Vec<Facet>, String> {
     check_bounds(bounds)?;
     let o = options.sanitized();
-    let rings = rings(path, bounds.width().max(bounds.height()), MAX_SOLID_POINTS)?;
+    let rings = rings(path, rule, bounds.width().max(bounds.height()), MAX_SOLID_POINTS)?;
     if rings.is_empty() {
         return Ok(vec![]);
     }

crates/three-d/src/tests_solid.rs

@@ -1,4 +1,4 @@
-use vectorcraft_geom::{BezPath, PathData, Point, Rect};
+use vectorcraft_geom::{BezPath, FillRule, PathData, Point, Rect};
 
 use super::*;
 
@@ -41,7 +41,7 @@ fn close(a: f64, b: f64, tol: f64) -> bool {
 #[test]
 fn seen_straight_on_an_extrusion_is_its_front_face_exactly_where_the_art_is() {
     let (p, b) = shape(&square(10.0, 20.0, 100.0));
-    let f = extrude(&p, b, Extrude::default(), front()).unwrap();
+    let f = extrude(&p, FillRule::EvenOdd, b, Extrude::default(), front()).unwrap();
     assert_eq!(f.len(), 1, "the walls and back face away: only the front cap shows");
     assert_eq!(f[0].contours.len(), 1);
     assert_eq!(extent(&f), Rect::new(10.0, 20.0, 110.0, 120.0));
@@ -51,7 +51,7 @@ fn seen_straight_on_an_extrusion_is_its_front_face_exactly_where_the_art_is() {
 fn turned_about_y_the_front_foreshortens_and_one_side_wall_shows() {
     let (p, b) = shape(&square(0.0, 0.0, 100.0));
     let o = Extrude { depth: 40.0, ..Extrude::default() };
-    let f = extrude(&p, b, o, View { rotation_y: 30.0, ..front() }).unwrap();
+    let f = extrude(&p, FillRule::EvenOdd, b, o, View { rotation_y: 30.0, ..front() }).unwrap();
     // Orthographic: the silhouette is the front's width times cos 30° plus the depth times sin 30°.
     let w = extent(&f).width();
     assert!(close(w, 100.0 * 30f64.to_radians().cos() + 40.0 * 30f64.to_radians().sin(), 1e-6), "{w}");
@@ -66,10 +66,10 @@ fn turned_about_y_the_front_foreshortens_and_one_side_wall_shows() {
 fn no_depth_is_the_flat_shape_and_no_cap_shows_the_inside() {
     let (p, b) = shape(&square(0.0, 0.0, 100.0));
     let v = View { rotation_x: 20.0, rotation_y: 30.0, ..front() };
-    let flat = extrude(&p, b, Extrude { depth: 0.0, ..Extrude::default() }, v).unwrap();
+    let flat = extrude(&p, FillRule::EvenOdd, b, Extrude { depth: 0.0, ..Extrude::default() }, v).unwrap();
-    assert_eq!(flat, plane(&p, b, v).unwrap());
+    assert_eq!(flat, plane(&p, FillRule::EvenOdd, b, v).unwrap());
-    let solid = extrude(&p, b, Extrude::default(), v).unwrap();
+    let solid = extrude(&p, FillRule::EvenOdd, b, Extrude::default(), v).unwrap();
-    let hollow = extrude(&p, b, Extrude { cap: false, ..Extrude::default() }, v).unwrap();
+    let hollow = extrude(&p, FillRule::EvenOdd, b, Extrude { cap: false, ..Extrude::default() }, v).unwrap();
     // Solid: front, right and top faces. Hollow: all four walls (two seen from inside), no caps.
     assert_eq!(solid.len(), 3);
     assert_eq!(hollow.len(), 4);
@@ -81,10 +81,10 @@ fn taper_shrinks_the_back_and_twist_turns_it() {
     let (p, b) = shape(&square(0.0, 0.0, 100.0));
     let side = View { rotation_y: 90.0, ..front() };
     let o = Extrude { depth: 60.0, cap: false, ..Extrude::default() };
-    let straight = extent(&extrude(&p, b, o, side).unwrap());
+    let straight = extent(&extrude(&p, FillRule::EvenOdd, b, o, side).unwrap());
     assert!(close(straight.height(), 100.0, 1e-6) && close(straight.width(), 60.0, 1e-6));
     // Seen from the side, a 50 % taper keeps the front's full height and halves the back's.
-    let tapered = extrude(&p, b, Extrude { taper: 0.5, ..o }, side).unwrap();
+    let tapered = extrude(&p, FillRule::EvenOdd, b, Extrude { taper: 0.5, ..o }, side).unwrap();
     let back: Vec<Point> = tapered.iter().flat_map(|f| f.contours.iter().flatten().copied()).filter(|q| close(q.x, straight.x0, 1e-6)).collect();
     let (lo, hi) = back.iter().fold((f64::INFINITY, f64::NEG_INFINITY), |(lo, hi), q| (lo.min(q.y), hi.max(q.y)));
     let at_front: Vec<Point> = tapered.iter().flat_map(|f| f.contours.iter().flatten().copied()).filter(|q| close(q.x, straight.x1, 1e-6)).collect();
@@ -93,11 +93,11 @@ fn taper_shrinks_the_back_and_twist_turns_it() {
     assert!(close(front_h, 100.0, 1e-6) && close(back_h, 50.0, 1e-6), "front {front_h}, back {back_h}");
     // Seen from behind, a 45° twist shows the back cap turned into a diamond.
     let back = View { rotation_y: 180.0, ..front() };
-    let twisted = extrude(&p, b, Extrude { twist: 45.0, cap: true, ..o }, back).unwrap();
+    let twisted = extrude(&p, FillRule::EvenOdd, b, Extrude { twist: 45.0, cap: true, ..o }, back).unwrap();
     assert_eq!(twisted.len(), 1, "only the back cap faces the viewer");
     assert!(close(extent(&twisted).width(), 100.0 * 2f64.sqrt(), 1e-6), "{:?}", extent(&twisted));
     // Its walls are cut into slices that follow the turn.
-    let open = extrude(&p, b, Extrude { twist: 45.0, ..o }, View { rotation_x: -20.0, rotation_y: 30.0, ..front() }).unwrap();
+    let open = extrude(&p, FillRule::EvenOdd, b, Extrude { twist: 45.0, ..o }, View { rotation_x: -20.0, rotation_y: 30.0, ..front() }).unwrap();
     assert!(open.len() > 2 * 8, "{}", open.len());
 }
 
@@ -105,13 +105,13 @@ fn taper_shrinks_the_back_and_twist_turns_it() {
 fn a_bevel_inside_shrinks_the_cap_and_outside_grows_the_walls() {
     let (p, b) = shape(&square(0.0, 0.0, 100.0));
     let bevel = Bevel { width: 10.0, height: 10.0, ..Bevel::default() };
-    let inside = extrude(&p, b, Extrude { bevel: Some(Bevel { inside: true, ..bevel }), ..Extrude::default() }, front()).unwrap();
+    let inside = extrude(&p, FillRule::EvenOdd, b, Extrude { bevel: Some(Bevel { inside: true, ..bevel }), ..Extrude::default() }, front()).unwrap();
     // Straight on: the cap inset by the width, and the chamfer around it filling the outline.
     let cap = inside.iter().find(|f| close(signed_area(&f.contours[0]).abs(), 80.0 * 80.0, 1e-6));
     assert!(cap.is_some(), "an 80 × 80 cap");
     assert_eq!(extent(&inside), Rect::new(0.0, 0.0, 100.0, 100.0));
     assert!(close(area(&inside), 100.0 * 100.0, 1e-6));
-    let outside = extrude(&p, b, Extrude { bevel: Some(bevel), ..Extrude::default() }, front()).unwrap();
+    let outside = extrude(&p, FillRule::EvenOdd, b, Extrude { bevel: Some(bevel), ..Extrude::default() }, front()).unwrap();
     assert_eq!(extent(&outside), Rect::new(-10.0, -10.0, 110.0, 110.0), "the walls stand 10 pt outside the art");
     assert!(outside.iter().any(|f| close(signed_area(&f.contours[0]).abs(), 100.0 * 100.0, 1e-6)), "the cap is the art");
     // The chamfer's faces lean towards the light differently from the cap.
@@ -123,12 +123,16 @@ fn bevel_shapes_repeats_and_both_sides_change_the_surface() {
     let (p, b) = shape(&square(0.0, 0.0, 100.0));
     let v = View { rotation_x: -20.0, rotation_y: 30.0, ..front() };
     let base = Bevel { width: 12.0, height: 12.0, ..Bevel::default() };
-    let classic = extrude(&p, b, Extrude { bevel: Some(base), ..Extrude::default() }, v).unwrap();
+    let classic = extrude(&p, FillRule::EvenOdd, b, Extrude { bevel: Some(base), ..Extrude::default() }, v).unwrap();
     for shape in BevelShape::ALL.into_iter().skip(1) {
-        assert_ne!(classic, extrude(&p, b, Extrude { bevel: Some(Bevel { shape, ..base }), ..Extrude::default() }, v).unwrap(), "{shape:?}");
+        assert_ne!(
+            classic,
+            extrude(&p, FillRule::EvenOdd, b, Extrude { bevel: Some(Bevel { shape, ..base }), ..Extrude::default() }, v).unwrap(),
+            "{shape:?}"
+        );
     }
     for bevel in [Bevel { repeat: 3, ..base }, Bevel { repeat: 3, space: 0.3, ..base }, Bevel { both_sides: true, ..base }] {
-        assert_ne!(classic, extrude(&p, b, Extrude { bevel: Some(bevel), ..Extrude::default() }, v).unwrap(), "{bevel:?}");
+        assert_ne!(classic, extrude(&p, FillRule::EvenOdd, b, Extrude { bevel: Some(bevel), ..Extrude::default() }, v).unwrap(), "{bevel:?}");
     }
     // The step shape keeps its corners: half the width at half the height.
     assert_eq!(BevelShape::Step.at(0.5), (0.5, 0.5));
@@ -147,11 +151,11 @@ fn holes_stay_holes_in_the_caps_and_get_walls_of_their_own() {
     // The hole drawn the same way round as the outline: even-odd nesting still makes it a hole.
     b.extend(square(30.0, 30.0, 40.0));
     let (p, r) = shape(&b);
-    let f = extrude(&p, r, Extrude::default(), front()).unwrap();
+    let f = extrude(&p, FillRule::EvenOdd, r, Extrude::default(), front()).unwrap();
     assert_eq!(f.len(), 1);
     assert_eq!(f[0].contours.len(), 2);
     assert!(close(area(&f), 100.0 * 100.0 - 40.0 * 40.0, 1e-6));
-    let turned = extrude(&p, r, Extrude::default(), View { rotation_y: 40.0, ..front() }).unwrap();
+    let turned = extrude(&p, FillRule::EvenOdd, r, Extrude::default(), View { rotation_y: 40.0, ..front() }).unwrap();
     // Front cap, the outline's right wall and the hole's left wall (seen through the hole).
     assert_eq!(turned.len(), 3);
 }
@@ -159,15 +163,15 @@ fn holes_stay_holes_in_the_caps_and_get_walls_of_their_own() {
 #[test]
 fn a_plane_turns_about_the_given_centre() {
     let (p, b) = shape(&square(0.0, 0.0, 100.0));
-    let f = plane(&p, b, View { rotation_y: 60.0, ..front() }).unwrap();
+    let f = plane(&p, FillRule::EvenOdd, b, View { rotation_y: 60.0, ..front() }).unwrap();
     assert_eq!(f.len(), 1);
     let e = extent(&f);
     assert!(close(e.width(), 50.0, 1e-6) && close(e.center().x, 50.0, 1e-9));
     // Turned about the centre of a larger box, the square moves as well as narrowing.
-    let wide = plane(&p, Rect::new(0.0, 0.0, 300.0, 100.0), View { rotation_y: 60.0, ..front() }).unwrap();
+    let wide = plane(&p, FillRule::EvenOdd, Rect::new(0.0, 0.0, 300.0, 100.0), View { rotation_y: 60.0, ..front() }).unwrap();
     assert!(close(extent(&wide).x0, 150.0 - 150.0 * 0.5, 1e-6));
     // Its back shows when turned past 90°: a plane is two-sided.
-    assert_eq!(plane(&p, b, View { rotation_y: 150.0, ..front() }).unwrap().len(), 1);
+    assert_eq!(plane(&p, FillRule::EvenOdd, b, View { rotation_y: 150.0, ..front() }).unwrap().len(), 1);
 }
 
 #[test]
@@ -175,7 +179,7 @@ fn inflate_covers_the_shape_and_puffs_by_the_volume() {
     let mut c = BezPath::new();
     c.extend(vectorcraft_geom::kurbo::Shape::path_elements(&vectorcraft_geom::kurbo::Circle::new((100.0, 100.0), 50.0), 0.01));
     let (p, b) = shape(&c);
-    let f = inflate(&p, b, Inflate::default(), front()).unwrap();
+    let f = inflate(&p, FillRule::EvenOdd, b, Inflate::default(), front()).unwrap();
     // Straight on, the cushion covers the circle (sampled as a polygon) and nothing else.
     assert!(close(area(&f), std::f64::consts::PI * 50.0 * 50.0, 60.0), "{}", area(&f));
     assert!(extent(&f).x0 >= 50.0 - 1e-6 && extent(&f).x1 <= 150.0 + 1e-6);
@@ -184,7 +188,7 @@ fn inflate_covers_the_shape_and_puffs_by_the_volume() {
     assert!(hi - lo > 0.3, "{lo}..{hi}");
     // From the side: 50 % volume rounds a disc into a half sphere on a flat back.
     let side = View { rotation_y: 90.0, ..front() };
-    let thick = |o: Inflate| extent(&inflate(&p, b, o, side).unwrap()).width();
+    let thick = |o: Inflate| extent(&inflate(&p, FillRule::EvenOdd, b, o, side).unwrap()).width();
     assert!(close(thick(Inflate::default()), 50.0, 2.0), "{}", thick(Inflate::default()));
     assert!(close(thick(Inflate { both_sides: true, ..Inflate::default() }), 100.0, 4.0));
     assert!(close(thick(Inflate { depth: 30.0, ..Inflate::default() }), 80.0, 2.0));
@@ -197,7 +201,7 @@ fn inflate_leaves_holes_open() {
     let mut b = square(0.0, 0.0, 100.0);
     b.extend(square(30.0, 30.0, 40.0));
     let (p, r) = shape(&b);
-    let f = inflate(&p, r, Inflate::default(), front()).unwrap();
+    let f = inflate(&p, FillRule::EvenOdd, r, Inflate::default(), front()).unwrap();
     assert!(close(area(&f), 100.0 * 100.0 - 40.0 * 40.0, 1e-3), "{}", area(&f));
 }
 
@@ -205,9 +209,9 @@ fn inflate_leaves_holes_open() {
 fn malformed_and_degenerate_input_is_bounded() {
     let (p, b) = shape(&square(0.0, 0.0, 100.0));
     for r in [Rect::new(f64::NAN, 0.0, 1.0, 1.0), Rect::new(0.0, 0.0, 1e9, 1.0)] {
-        assert!(extrude(&p, r, Extrude::default(), front()).is_err());
+        assert!(extrude(&p, FillRule::EvenOdd, r, Extrude::default(), front()).is_err());
-        assert!(inflate(&p, r, Inflate::default(), front()).is_err());
+        assert!(inflate(&p, FillRule::EvenOdd, r, Inflate::default(), front()).is_err());
-        assert!(plane(&p, r, front()).is_err());
+        assert!(plane(&p, FillRule::EvenOdd, r, front()).is_err());
     }
     let wild = Extrude {
         depth: f64::INFINITY,
@@ -216,18 +220,24 @@ fn malformed_and_degenerate_input_is_bounded() {
         cap: true,
         bevel: Some(Bevel { width: f64::NAN, height: 1e12, repeat: usize::MAX, space: 7.0, ..Bevel::default() }),
     };
-    let f = extrude(&p, b, wild, View { rotation_x: f64::NAN, perspective: 900.0, ..front() }).unwrap();
+    let f = extrude(&p, FillRule::EvenOdd, b, wild, View { rotation_x: f64::NAN, perspective: 900.0, ..front() }).unwrap();
     assert!(f.iter().flat_map(|f| f.contours.iter().flatten()).all(|q| q.x.is_finite() && q.y.is_finite()));
     assert!(
-        inflate(&p, b, Inflate { depth: -5.0, volume: f64::NAN, both_sides: true, twist: f64::INFINITY, taper: f64::NAN, cap: true }, front())
+        inflate(
-            .is_ok()
+            &p,
+            FillRule::EvenOdd,
+            b,
+            Inflate { depth: -5.0, volume: f64::NAN, both_sides: true, twist: f64::INFINITY, taper: f64::NAN, cap: true },
+            front()
+        )
+        .is_ok()
     );
-    assert!(extrude(&PathData::default(), b, Extrude::default(), front()).unwrap().is_empty());
+    assert!(extrude(&PathData::default(), FillRule::EvenOdd, b, Extrude::default(), front()).unwrap().is_empty());
     // A line has no area to extrude.
     let mut line = BezPath::new();
     line.move_to((0.0, 0.0));
     line.line_to((100.0, 0.0));
-    assert!(extrude(&PathData::from_bezpath(&line), b, Extrude::default(), front()).unwrap().is_empty());
+    assert!(extrude(&PathData::from_bezpath(&line), FillRule::EvenOdd, b, Extrude::default(), front()).unwrap().is_empty());
     // Too many anchors: refused, not truncated.
     let mut many = BezPath::new();
     many.move_to((0.0, 0.0));
@@ -235,15 +245,15 @@ fn malformed_and_degenerate_input_is_bounded() {
         many.line_to((f64::from(i), f64::from(i % 7)));
     }
     many.close_path();
-    assert!(extrude(&PathData::from_bezpath(&many), b, Extrude::default(), front()).is_err());
+    assert!(extrude(&PathData::from_bezpath(&many), FillRule::EvenOdd, b, Extrude::default(), front()).is_err());
 }
 
 #[test]
 fn perspective_makes_the_near_face_larger() {
     let (p, b) = shape(&square(0.0, 0.0, 100.0));
     let o = Extrude { depth: 100.0, ..Extrude::default() };
-    let flat = extent(&extrude(&p, b, o, front()).unwrap());
+    let flat = extent(&extrude(&p, FillRule::EvenOdd, b, o, front()).unwrap());
-    let deep = extent(&extrude(&p, b, o, View { perspective: 30.0, ..front() }).unwrap());
+    let deep = extent(&extrude(&p, FillRule::EvenOdd, b, o, View { perspective: 30.0, ..front() }).unwrap());
     assert!(deep.width() > flat.width() + 1.0);
     assert!(close(deep.center().x, flat.center().x, 1e-6));
 }
@@ -257,7 +267,7 @@ fn a_wider_perspective_brings_the_eye_nearer() {
     let mut last = 100.0;
     for angle in [20.0, 60.0, 110.0, 160.0] {
         // The front face alone shows: its width is the cube's on the page.
-        let width = extent(&extrude(&p, b, o, View { perspective: angle, ..front() }).unwrap()).width();
+        let width = extent(&extrude(&p, FillRule::EvenOdd, b, o, View { perspective: angle, ..front() }).unwrap()).width();
         assert!(width > last, "{angle}°: {width} after {last}");
         last = width;
     }
@@ -274,10 +284,10 @@ fn the_inflate_membrane_matches_known_solutions() {
     let mut c = BezPath::new();
     c.extend(vectorcraft_geom::kurbo::Shape::path_elements(&vectorcraft_geom::kurbo::Circle::new((100.0, 100.0), 50.0), 0.01));
     let (p, b) = shape(&c);
-    let disc = Membrane::solve(&rings(&p, 100.0, MAX_SOLID_POINTS).unwrap(), b.origin(), b.width() / 48.0, 49, 49);
+    let disc = Membrane::solve(&rings(&p, FillRule::EvenOdd, 100.0, MAX_SOLID_POINTS).unwrap(), b.origin(), b.width() / 48.0, 49, 49);
     assert!(close(disc.peak, 50.0 * 50.0 / 4.0, 625.0 * 0.02), "{}", disc.peak);
     let (p, b) = shape(&square(0.0, 0.0, 100.0));
-    let sq = Membrane::solve(&rings(&p, 100.0, MAX_SOLID_POINTS).unwrap(), b.origin(), 100.0 / 48.0, 49, 49);
+    let sq = Membrane::solve(&rings(&p, FillRule::EvenOdd, 100.0, MAX_SOLID_POINTS).unwrap(), b.origin(), 100.0 / 48.0, 49, 49);
     assert!(close(sq.peak, 0.07367 * 100.0 * 100.0, 736.7 * 0.02), "{}", sq.peak);
     // Smooth across the middle: no crease where a distance-to-the-edge height would have one
     // (the diagonals). The second difference along a diagonal stays small and even.
@@ -303,10 +313,10 @@ fn inflate_cells_across_a_hole_edge_are_cut_to_the_shape() {
     b.close_path();
     let (p, r) = shape(&b);
     let v = View { rotation_x: -21.88, rotation_y: -23.4, rotation_z: 9.06, ..front() };
-    let f = inflate(&p, r, Inflate::default(), v).unwrap();
+    let f = inflate(&p, FillRule::EvenOdd, r, Inflate::default(), v).unwrap();
     assert!(f.iter().all(|f| f.contours.len() == 1), "every facet is one piece of the surface");
     // Straight on, the facets still cover exactly the shape.
-    let flat = inflate(&p, r, Inflate::default(), front()).unwrap();
+    let flat = inflate(&p, FillRule::EvenOdd, r, Inflate::default(), front()).unwrap();
     assert!(close(area(&flat), 220.0 * 220.0 - 100.0 * 90.0, 1e-3), "{}", area(&flat));
 }
 
@@ -332,19 +342,19 @@ fn bumps(count: usize) -> (PathData, Rect) {
 fn small_curves_take_few_points_and_rotate_takes_large_outlines() {
     // 300 curves were 4,800 points at sixteen each, over the old limit of 1,024.
     let (p, r) = bumps(300);
-    assert!(extrude(&p, r, Extrude::default(), front()).is_ok());
+    assert!(extrude(&p, FillRule::EvenOdd, r, Extrude::default(), front()).is_ok());
-    assert!(inflate(&p, r, Inflate { volume: 20.0, ..Inflate::default() }, front()).is_ok());
+    assert!(inflate(&p, FillRule::EvenOdd, r, Inflate { volume: 20.0, ..Inflate::default() }, front()).is_ok());
-    assert!(plane(&p, r, front()).is_ok());
+    assert!(plane(&p, FillRule::EvenOdd, r, front()).is_ok());
     // 4,000 curves: too many for a solid, not for Rotate.
     let (p, r) = bumps(4000);
-    assert!(extrude(&p, r, Extrude::default(), front()).unwrap_err().contains("too complex"));
+    assert!(extrude(&p, FillRule::EvenOdd, r, Extrude::default(), front()).unwrap_err().contains("too complex"));
-    assert_eq!(plane(&p, r, front()).unwrap().len(), 1);
+    assert_eq!(plane(&p, FillRule::EvenOdd, r, front()).unwrap().len(), 1);
     // Each piece stays within the tolerance of the curve: a circle's chords sag at most 0.05 pt
     // here (1/2000 of its 100 pt size is less).
     let mut c = BezPath::new();
     c.extend(vectorcraft_geom::kurbo::Shape::path_elements(&vectorcraft_geom::kurbo::Circle::new((50.0, 50.0), 50.0), 0.01));
     let (p, r) = shape(&c);
-    let ring = &rings(&p, 100.0, MAX_SOLID_POINTS).unwrap()[0];
+    let ring = &rings(&p, FillRule::EvenOdd, 100.0, MAX_SOLID_POINTS).unwrap()[0];
     for (a, b) in ring.iter().zip(ring.iter().cycle().skip(1)) {
         let mid = a.midpoint(*b);
         assert!(50.0 - mid.distance(Point::new(50.0, 50.0)) <= 0.05 + 1e-3, "{a:?} {b:?}");
@@ -352,7 +362,7 @@ fn small_curves_take_few_points_and_rotate_takes_large_outlines() {
     assert!(r.width() > 0.0);
     // A small bump takes a few points; a large curve more than sixteen where it needs them.
     let (p, r) = bumps(300);
-    let small = rings(&p, r.width().max(r.height()), MAX_SOLID_POINTS).unwrap()[0].len();
+    let small = rings(&p, FillRule::EvenOdd, r.width().max(r.height()), MAX_SOLID_POINTS).unwrap()[0].len();
     assert!(small <= 300 * 4 + 3, "{small} points for 300 bumps");
     assert!(ring.len() > 4 * 16, "a 100 pt circle within 0.05 pt: {}", ring.len());
 }
@@ -362,7 +372,7 @@ fn small_curves_take_few_points_and_rotate_takes_large_outlines() {
 #[test]
 fn the_edge_index_finds_the_nearest_edge() {
     let (p, r) = bumps(200);
-    let rings = rings(&p, r.width(), MAX_SOLID_POINTS).unwrap();
+    let rings = rings(&p, FillRule::EvenOdd, r.width(), MAX_SOLID_POINTS).unwrap();
     let edges = Edges::new(&rings);
     for k in 0..400 {
         let t = f64::from(k);
@@ -376,7 +386,7 @@ fn the_edge_index_finds_the_nearest_edge() {
 /// straight ahead: the search doesn't stop before it has looked there.
 #[test]
 fn the_edge_index_looks_along_the_side_from_outside() {
-    let ring = |b: BezPath| rings(&shape(&b).0, 64.0, MAX_SOLID_POINTS).unwrap().remove(0);
+    let ring = |b: BezPath| rings(&shape(&b).0, FillRule::EvenOdd, 64.0, MAX_SOLID_POINTS).unwrap().remove(0);
     // Straight ahead of the point, a little further up its side, and the far corner (a 64 pt grid).
     let rings = vec![ring(square(2.5, 0.0, 1.0)), ring(square(0.0, 4.2, 0.8)), ring(square(63.0, 63.0, 1.0))];
     let edges = Edges::new(&rings);
@@ -390,7 +400,7 @@ fn the_edge_index_looks_along_the_side_from_outside() {
 fn twist_holds_between_0_and_360_degrees() {
     let (p, b) = shape(&square(0.0, 0.0, 100.0));
     let v = View { rotation_x: -20.0, rotation_y: 30.0, ..front() };
-    let at = |twist: f64| extrude(&p, b, Extrude { twist, ..Extrude::default() }, v).unwrap();
+    let at = |twist: f64| extrude(&p, FillRule::EvenOdd, b, Extrude { twist, ..Extrude::default() }, v).unwrap();
     assert_eq!(at(-45.0), at(0.0));
     assert_eq!(at(500.0), at(360.0));
     assert_ne!(at(45.0), at(0.0));
@@ -408,11 +418,11 @@ fn twisted_walls_face_the_way_they_turn() {
         for (x, y) in [(-20.0, 30.0), (0.0, 90.0), (30.0, -60.0), (-45.0, 150.0)] {
             let v = View { rotation_x: x, rotation_y: y, ..front() };
             let o = Extrude { twist, ..Extrude::default() };
-            let got = extrude(&p, b, o, v).unwrap();
+            let got = extrude(&p, FillRule::EvenOdd, b, o, v).unwrap();
             // Expected: walls (and caps) whose outward normal faces the viewer.
             let o = o.sanitized();
             let camera = Camera::new(v, b, o.depth);
-            let ring = &rings(&p, b.width().max(b.height()), MAX_SOLID_POINTS).unwrap()[0];
+            let ring = &rings(&p, FillRule::EvenOdd, b.width().max(b.height()), MAX_SOLID_POINTS).unwrap()[0];
             let slices = ((twist / 6.0).ceil() as usize).clamp(8, 64);
             let z = |t: f64| o.depth / 2.0 - o.depth * t;
             let mut expected = 0;
@@ -456,7 +466,7 @@ fn inflate_twists_tapers_and_opens_its_back() {
     let o = Inflate { depth: 60.0, volume: 0.0, ..Inflate::default() };
     // From the side, a flat (0 % volume) cushion is the extrusion: front 100 high, the back 50
     // at a 50 % taper.
-    let tapered = inflate(&p, b, Inflate { taper: 0.5, ..o }, side).unwrap();
+    let tapered = inflate(&p, FillRule::EvenOdd, b, Inflate { taper: 0.5, ..o }, side).unwrap();
     let e = extent(&tapered);
     assert!(close(e.width(), 60.0, 1e-6) && close(e.height(), 100.0, 1e-6), "{e:?}");
     let back: Vec<Point> = tapered.iter().flat_map(|f| f.contours.iter().flatten().copied()).filter(|q| close(q.x, e.x0, 1e-6)).collect();
@@ -464,18 +474,19 @@ fn inflate_twists_tapers_and_opens_its_back() {
     assert!(close(hi - lo, 50.0, 1e-6), "back {}", hi - lo);
     // From behind, a 45° twist shows the flat back as a diamond.
     let behind = View { rotation_y: 180.0, ..front() };
-    let twisted = inflate(&p, b, Inflate { twist: 45.0, ..o }, behind).unwrap();
+    let twisted = inflate(&p, FillRule::EvenOdd, b, Inflate { twist: 45.0, ..o }, behind).unwrap();
     assert!(close(extent(&twisted).width(), 100.0 * 2f64.sqrt(), 1e-6), "{:?}", extent(&twisted));
     // Hollow: no back; from behind the inside of the inflated front shows instead of a flat face.
-    let solid = inflate(&p, b, Inflate { volume: 50.0, ..o }, behind).unwrap();
+    let solid = inflate(&p, FillRule::EvenOdd, b, Inflate { volume: 50.0, ..o }, behind).unwrap();
     assert_eq!(solid.len(), 1, "the flat back alone");
-    let hollow = inflate(&p, b, Inflate { volume: 50.0, cap: false, ..o }, behind).unwrap();
+    let hollow = inflate(&p, FillRule::EvenOdd, b, Inflate { volume: 50.0, cap: false, ..o }, behind).unwrap();
     assert!(hollow.len() > 100 && hollow.iter().all(|f| f.contours.len() == 1 && f.contours[0].len() < 12));
     // With both sides puffed, the back puff is scaled with the taper: lower and smaller.
-    let both = |taper: f64| extent(&inflate(&p, b, Inflate { both_sides: true, volume: 50.0, taper, depth: 0.0, ..o }, side).unwrap());
+    let both =
+        |taper: f64| extent(&inflate(&p, FillRule::EvenOdd, b, Inflate { both_sides: true, volume: 50.0, taper, depth: 0.0, ..o }, side).unwrap());
     assert!(both(0.5).width() < both(1.0).width() && both(0.5).height() <= both(1.0).height() + 1e-6);
     // Out of range values hold at the documented ends.
-    let at = |i: Inflate| inflate(&p, b, i, View { rotation_x: -20.0, rotation_y: 30.0, ..front() }).unwrap();
+    let at = |i: Inflate| inflate(&p, FillRule::EvenOdd, b, i, View { rotation_x: -20.0, rotation_y: 30.0, ..front() }).unwrap();
     assert_eq!(at(Inflate { twist: -30.0, ..o }), at(o));
     assert_eq!(at(Inflate { taper: 0.0, ..o }), at(Inflate { taper: 0.01, ..o }));
 }
@@ -487,10 +498,43 @@ fn a_flat_twisted_inflate_matches_the_extrusion() {
     let (p, b) = shape(&square(0.0, 0.0, 100.0));
     for (x, y) in [(-20.0, 30.0), (0.0, 90.0), (30.0, -60.0), (-45.0, 150.0), (60.0, 200.0)] {
         let v = View { rotation_x: x, rotation_y: y, ..front() };
-        let e = extent(&extrude(&p, b, Extrude { depth: 60.0, twist: 120.0, taper: 0.6, ..Extrude::default() }, v).unwrap());
+        let e = extent(&extrude(&p, FillRule::EvenOdd, b, Extrude { depth: 60.0, twist: 120.0, taper: 0.6, ..Extrude::default() }, v).unwrap());
-        let i = extent(&inflate(&p, b, Inflate { depth: 60.0, twist: 120.0, taper: 0.6, volume: 0.0, ..Inflate::default() }, v).unwrap());
+        let i = extent(
+            &inflate(&p, FillRule::EvenOdd, b, Inflate { depth: 60.0, twist: 120.0, taper: 0.6, volume: 0.0, ..Inflate::default() }, v).unwrap(),
+        );
         for (a, c) in [(e.x0, i.x0), (e.y0, i.y0), (e.x1, i.x1), (e.y1, i.y1)] {
             assert!(close(a, c, 1e-6), "view ({x}, {y}): extrusion {e:?}, inflate {i:?}");
         }
     }
 }
+
+/// #1724: under the nonzero rule a contour inside another that runs the same way cuts no hole
+/// (the middle is filled, as the art is drawn); one running the other way does, and so does
+/// either under the even-odd rule.
+#[test]
+fn nonzero_shapes_keep_the_middle_a_same_way_contour_encloses() {
+    let rect = |r: Rect, clockwise: bool| {
+        let mut pts = vec![Point::new(r.x0, r.y0), Point::new(r.x1, r.y0), Point::new(r.x1, r.y1), Point::new(r.x0, r.y1)];
+        if clockwise {
+            pts.reverse();
+        }
+        vectorcraft_geom::SubPath::polyline(&pts, true)
+    };
+    let (outer, inner) = (Rect::new(0.0, 0.0, 100.0, 100.0), Rect::new(25.0, 25.0, 75.0, 75.0));
+    let nested = |inner_clockwise: bool| PathData::new(vec![rect(outer, false), rect(inner, inner_clockwise)]);
+    let flat = |p: &PathData, rule: FillRule| area(&plane(p, rule, outer, front()).unwrap());
+    let (solid, holed) = (100.0 * 100.0, 100.0 * 100.0 - 50.0 * 50.0);
+    assert!(close(flat(&nested(false), FillRule::NonZero), solid, 1e-6), "the same way round: filled");
+    assert!(close(flat(&nested(true), FillRule::NonZero), holed, 1e-6), "the other way round: a hole");
+    assert!(close(flat(&nested(false), FillRule::EvenOdd), holed, 1e-6));
+    assert!(close(flat(&nested(true), FillRule::EvenOdd), holed, 1e-6));
+    // A third contour inside the hole is an island again, whichever way it runs.
+    let island = |clockwise: bool| PathData::new(vec![rect(outer, false), rect(inner, true), rect(Rect::new(40.0, 40.0, 60.0, 60.0), clockwise)]);
+    for clockwise in [false, true] {
+        assert!(close(flat(&island(clockwise), FillRule::NonZero), holed + 20.0 * 20.0, 1e-6), "{clockwise}");
+    }
+    // Extrude's caps and Inflate follow the same outline.
+    let caps = |p: &PathData| area(&extrude(p, FillRule::NonZero, outer, Extrude::default(), front()).unwrap());
+    assert!(caps(&nested(false)) > caps(&nested(true)) + 1000.0);
+    assert!(inflate(&nested(false), FillRule::NonZero, outer, Inflate::default(), front()).is_ok());
+}