Export: the art's bounds take in the effects of groups, type and images

The bounds of the visible art (`vectorcraft_render::encode::art_bounds`)
are the crop of Export with Use Artboards off, EPS without artboards,
Export for Screens' Full Document and Save for Web (Legacy) with Clip to
Artboard off, and the size Fit to Artwork Bounds gives an artboard. They
measured a group or layer by its members and left out its own effects,
and measured type and images without their effects. A group's drop
shadow, or the shadow of a line of type, was cut off at the image's edge
and left outside the fitted artboard. They also counted a Shaper group's
transparent source art.

Each visible object is now measured by `vectorcraft_render::effect_bounds`,
the measure of Export Selection's crop. A group or layer without effects
of its own is still measured by its visible members, skipping a Shaper
group's source art. A group or layer with a drop shadow, a glow or another
raster effect is measured without its hidden members, guides and template
layers, unless it is a Shaper group or also has a geometry, Pathfinder,
Crop Marks or 3D effect or a visible effect on its own fill or stroke.
The SVG of a chosen artboard also keeps an object whose effects alone
reach the artboard.

Docs: docs/mcp.md, docs/target-app-parity.md.

crates/engine/src/cmd/fileio/export.rs

@@ -94,11 +94,12 @@ fn selected_part(n: &Node, keep: &HashSet<NodeId>) -> Option<Node> {
 }
 
 /// `doc` with only the art over `rect` (an artboard): objects whose visual bounds miss it are left
-/// out, at any depth of layers, sublayers and groups that don't clip, and objects that reach it
-/// stay whole (the file's bounds clip them), as DXF's crop leaves them. Symbol instances are
-/// measured by their art, and the box of one whose art holds brushed strokes grows by as far as
-/// their brush art can paint ([`SymbolBoxes::with_brush_art`]). An object that holds a symbol
-/// instance also stays when what the canvas paints for it reaches `rect`
+/// out, at any depth of layers, sublayers and groups that don't clip, unless what the renderer
+/// draws for them, their effects included ([`vectorcraft_render::effect_bounds`]), reaches it.
+/// Objects that reach it stay whole (the file's bounds clip them), as DXF's crop leaves them.
+/// Symbol instances are measured by their art, and the box of one whose art holds brushed strokes
+/// grows by as far as their brush art can paint ([`SymbolBoxes::with_brush_art`]). An object that
+/// holds a symbol instance also stays when what the canvas paints for it reaches `rect`
 /// ([`vectorcraft_render::painted_bounds`]: the effects in the symbols' art and its own effects). A
 /// clipping layer keeps every object, its clipping path among them. An artboard's file then holds
 /// its own art, not a whole document of artboards.
@@ -122,8 +123,9 @@ pub(super) fn art_over(doc: &Document, rect: vectorcraft_geom::Rect) -> Document
         let over = |b: vectorcraft_geom::Rect| b.x0 <= rect.x1 && rect.x0 <= b.x1 && b.y0 <= rect.y1 && rect.y0 <= b.y1;
         let mut holds_instance = false;
         n.walk(&mut |c| holds_instance |= matches!(c.kind, NodeKind::SymbolInstance { .. }));
+        let drawn = || vectorcraft_render::effect_bounds(symbols, n).is_some_and(over);
         let painted = || holds_instance && vectorcraft_render::painted_bounds(doc, n).is_some_and(over);
-        (n.visual_bounds_with(symbols).is_none_or(over) || painted()).then(|| n.clone())
+        (n.visual_bounds_with(symbols).is_none_or(over) || drawn() || painted()).then(|| n.clone())
     }
     let symbols = doc.symbol_boxes().with_brush_art();
     let mut d = doc.clone();

crates/engine/src/cmd/fileio/tests_svgenc.rs

@@ -91,3 +91,20 @@ fn a_chosen_artboard_s_svg_leaves_out_its_neighbours_art_in_a_shared_group() {
     assert_eq!(third_only.matches("<path").count() + third_only.matches("<rect").count(), 1, "{third_only}");
     assert!(third_only.contains(" C") || third_only.contains("<ellipse"), "{third_only}");
 }
+
+/// An object off a chosen artboard whose drop shadow reaches onto it is in that artboard's SVG.
+#[test]
+fn a_chosen_artboard_s_svg_keeps_an_object_whose_shadow_reaches_it() {
+    let mut s = Session::new();
+    s.execute("file.new", &json!({"width": 100, "height": 100})).unwrap();
+    let x0 = s.doc().unwrap().doc.artboards[0].rect.x0;
+    let id = s.execute("shape.rectangle", &json!({"x": x0 - 30.0, "y": 10, "width": 20, "height": 20})).unwrap()["id"].as_u64().unwrap();
+    let paths = |s: &mut Session| {
+        let svg = s.execute("document.serialize", &json!({"format": "svg", "artboard": 0})).unwrap();
+        let text = svg["text"].as_str().unwrap().to_string();
+        text.matches("<path").count() + text.matches("<rect").count()
+    };
+    assert_eq!(paths(&mut s), 0, "the plain rectangle is off the artboard");
+    s.execute("effect.apply", &json!({"effect": "stylize.dropShadow", "ids": [id], "params": {"x": 20, "y": 0, "blur": 0}})).unwrap();
+    assert_eq!(paths(&mut s), 1, "its shadow reaches 10 pt onto the artboard");
+}