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/tests_file.rs

@@ -260,6 +260,39 @@ fn export_selection_keeps_a_groups_shadow_in_the_crop() {
     assert!(img.get_pixel((155.0 - b[0]) as u32, img.height() / 2)[3] > 0, "the shadow is in the image");
 }
 
+/// Export with Use Artboards off and Fit to Artwork Bounds take in the drop shadow of a group and
+/// of type.
+#[test]
+fn the_arts_bounds_take_in_the_shadow_of_a_group_and_of_type() {
+    for kind in ["group", "type"] {
+        let mut s = session();
+        let id = if kind == "group" {
+            s.execute("shape.rectangle", &json!({"x": 100, "y": 100, "width": 20, "height": 20})).unwrap();
+            s.execute("shape.rectangle", &json!({"x": 130, "y": 100, "width": 20, "height": 20})).unwrap();
+            s.execute("select.all", &json!({})).unwrap();
+            s.execute("object.group", &json!({})).unwrap()["id"].as_u64().unwrap()
+        } else {
+            s.execute("text.create", &json!({"x": 100, "y": 120, "text": "Hill"})).unwrap()["id"].as_u64().unwrap()
+        };
+        let plain = s.doc().unwrap().doc.node(NodeId(id)).unwrap().visual_bounds().unwrap();
+        s.execute("effect.apply", &json!({"effect": "stylize.dropShadow", "ids": [id], "params": {"x": 8, "y": 0, "blur": 0}})).unwrap();
+        s.execute("select.set", &json!({"ids": [id]})).unwrap();
+        let png = |v: &serde_json::Value| {
+            image::load_from_memory(&vectorcraft_format::base64_decode(v["dataBase64"].as_str().unwrap()).unwrap()).unwrap().to_rgba8()
+        };
+        let art = s.execute("document.export", &json!({"format": "png", "useArtboards": false, "background": "transparent"})).unwrap();
+        let sel = s.execute("document.exportSelection", &json!({"format": "png", "background": "transparent"})).unwrap();
+        let x0 = sel["bounds"][0].as_f64().unwrap();
+        let img = png(&art);
+        assert!(png(&sel) == img, "{kind}: the same image as Export Selection's");
+        let past = (plain.x1 + 1.0 - x0).ceil() as u32;
+        assert!(img.enumerate_pixels().any(|(x, _, p)| x >= past && p[3] > 0), "{kind}: the shadow is in the image, right of the object");
+        s.execute("artboard.fitToArt", &json!({})).unwrap();
+        let board = s.doc().unwrap().doc.artboards[0].rect;
+        assert!(board.x0 <= plain.x0 && board.x1 >= plain.x1 + 8.0, "{kind}: the artboard holds the shadow 8 pt right of {plain:?}: {board:?}");
+    }
+}
+
 /// The crop of a brushed path is its visual bounds, with no room added for brush art.
 #[test]
 fn export_selection_crops_a_brushed_path_to_its_visual_bounds() {