M0.6: content bounds helpers for viewer handles

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

crates/render/src/lib.rs

@@ -332,3 +332,22 @@ pub fn render_frame(project: &Project, comp: ItemId, t: Tick, scale: f64) -> Ima
 
 #[cfg(test)]
 mod tests;
+
+/// Layer-space bounds `[x0, y0, x1, y1]` of a layer's content at the context time (source size
+/// for solids/footage/precomps, glyph bounds for text, painted bounds for shapes). Used for viewer
+/// handles and hit testing.
+pub fn content_bounds(ctx: &EvalCtx, layer: &effectcraft_project::Layer) -> Option<[f64; 4]> {
+    match &layer.source {
+        LayerSource::Text => {
+            let glyphs = text::glyph_paths(ctx, layer);
+            let paths: Vec<_> = glyphs.into_iter().map(|g| g.0).collect();
+            effectcraft_path::bounds(&paths).map(|r| [r.x0, r.y0, r.x1, r.y1])
+        }
+        LayerSource::Shape => layer.props.sub("contents").and_then(|c| shapes::content_bounds(ctx, layer, c)).map(|r| [r.x0, r.y0, r.x1, r.y1]),
+        LayerSource::Camera | LayerSource::Light { .. } => None,
+        _ => {
+            let (w, h) = source_size(ctx.project, layer);
+            (w > 0 && h > 0).then_some([0.0, 0.0, w as f64, h as f64])
+        }
+    }
+}

crates/render/src/shapes.rs

@@ -485,3 +485,17 @@ pub fn render(ctx: &EvalCtx, layer: &Layer, contents: &PropGroup, s: f64) -> Buf
 
 #[cfg(test)]
 mod tests;
+
+/// Layer-space bounds of a shape layer's painted contents (strokes included), without
+/// rasterising.
+pub fn content_bounds(ctx: &EvalCtx, layer: &Layer, contents: &PropGroup) -> Option<kurbo::Rect> {
+    let mut arena = Vec::new();
+    let (draws, _) = collect(ctx, layer, contents, &mut arena);
+    draws
+        .iter()
+        .filter_map(|d| {
+            let paths: Vec<BezPath> = d.slots.iter().map(|&i| arena[i].clone()).filter(|p| !p.elements().is_empty()).collect();
+            draw_bounds(d, &paths)
+        })
+        .reduce(|a, b| a.union(b))
+}