M4.58: raster effects in PDF on every kind of object

PDF export now renders the shadows, glows, blurs and feathers of groups,
layers, type, images, symbol instances, live objects and single fills and
strokes (and those inside opacity masks, symbol definitions and pattern
tiles) as images at the document raster effects resolution, instead of
leaving them out with a warning. Shadows and outer glows go under the
untouched vector art; a path whose fills or strokes carry effects is
written as one piece per fill and stroke. Expand Appearance shares the
image helpers (moved to rasterfx.rs); effect images now cover what the
renderer paints (members' shadows included).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

crates/render/src/lib.rs

@@ -36,6 +36,12 @@ pub use pattern::render_pattern_swatch;
 pub use vectorcraft_effects as effects;
 pub use vello_cpu;
 
+/// Bounds of everything `n` paints, as the renderer culls it: its members, strokes, brush art and
+/// geometry effects, and the shadows and glows of it and its members.
+pub fn painted_bounds(n: &Node) -> Option<Rect> {
+    brush_fx::cull_bounds(n)
+}
+
 /// Largest raster an export may ask [`Renderer::render_region`] for, per side. The CPU rasteriser
 /// addresses at most `u16::MAX` pixels per side (and panics at that edge).
 pub const MAX_RASTER_SIDE: u32 = 32_768;