Render: a 3-D picture's border stays centred on its edge

Follow-up to drawing picture borders outside the picture: PowerPoint does
that for flat pictures only. A picture seen through a 3-D scene with a
bevel (a common picture style) gets its border centred on the edge like
any shape: observed with an 18 pt border, which then covers 9 pt of the
picture. The corpus deck 60810 (white-framed bevelled screenshots) showed
the screenshots' own edges once the border moved out; it now matches
PowerPoint again.

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

crates/render/src/lib.rs

@@ -875,7 +875,7 @@ impl Renderer {
                 };
                 let (base, rel) = self.line_space(m, depth);
                 let lw = line.width.unwrap_or(0.75).max(0.0);
-                let outside = if is_pic { outside_line(&line, lw) } else { None };
+                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);
@@ -1000,8 +1000,8 @@ impl Renderer {
                 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.
-            let outside = is_pic.then(|| outside_line(&line, lw)).flatten();
+            // 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) => {
@@ -1242,6 +1242,13 @@ 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).

crates/render/src/tests_wild.rs

@@ -371,3 +371,19 @@ fn a_linear_gradient_spans_its_tile_rect() {
     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));
+}