perf(canvas): skip idle reveal node checks

crates/op-editor-ui/src/widgets/canvas_viewport.rs

@@ -481,19 +481,28 @@ impl<'a> Widget for CanvasViewport<'a> {
                     rect.size.y + CULL_MARGIN * 2.0,
                 ),
             };
+            let reveal_schedule = reveal_schedule_for_paint(&indicators.reveals, self.now_ms);
             for child in page.children.iter().rev() {
-                super::canvas_viewport_paint::paint_node_with_reveals(
-                    cx,
-                    child,
-                    viewport_origin,
-                    viewport.zoom,
-                    edit_caret.clone(),
-                    cull,
-                    super::canvas_viewport_paint::RevealSchedule {
-                        starts: &indicators.reveals,
-                        now_ms: self.now_ms,
-                    },
-                );
+                if let Some(reveals) = reveal_schedule {
+                    super::canvas_viewport_paint::paint_node_with_reveals(
+                        cx,
+                        child,
+                        viewport_origin,
+                        viewport.zoom,
+                        edit_caret.clone(),
+                        cull,
+                        reveals,
+                    );
+                } else {
+                    super::canvas_viewport_paint::paint_node(
+                        cx,
+                        child,
+                        viewport_origin,
+                        viewport.zoom,
+                        edit_caret.clone(),
+                        cull,
+                    );
+                }
             }
             super::canvas_agent_overlay::paint_agent_frame_indicators_with_snapshot(
                 cx,
@@ -710,6 +719,16 @@ impl<'a> Widget for CanvasViewport<'a> {
     }
 }
 
+pub(crate) fn reveal_schedule_for_paint<'a>(
+    reveals: &'a std::collections::HashMap<String, u64>,
+    now_ms: u64,
+) -> Option<super::canvas_viewport_paint::RevealSchedule<'a>> {
+    (!reveals.is_empty()).then_some(super::canvas_viewport_paint::RevealSchedule {
+        starts: reveals,
+        now_ms,
+    })
+}
+
 /// Stroke a dashed rectangle as 4 dashed edges (4 px on / 4 px off,
 /// screen-space) — the `RenderBackend` trait has no path-effect
 /// surface, so the dash is segmented by hand; backend-agnostic.

crates/op-editor-ui/src/widgets/canvas_viewport_tests.rs

@@ -6,6 +6,7 @@
 use super::*;
 use crate::layout_scene::{LayoutScene, SceneFillType, SceneNode, ScenePage, SceneStroke};
 use crate::{Color, Point2D, Rect, TextLayout};
+use std::collections::HashMap;
 
 /// Records op order; clip-isolated paint = `Save, Clip, Fill, …, Restore`.
 #[derive(Debug, PartialEq, Eq)]
@@ -217,6 +218,20 @@ fn grid_dot_count_matches_painted_dot_batch() {
     );
 }
 
+#[test]
+fn empty_reveals_use_plain_node_paint_path() {
+    let empty = HashMap::new();
+    assert!(
+        reveal_schedule_for_paint(&empty, 1_000).is_none(),
+        "idle canvas paint should not give every node an empty reveal lookup"
+    );
+
+    let active = HashMap::from([("n1".to_string(), 1_000)]);
+    let schedule = reveal_schedule_for_paint(&active, 1_250).expect("active reveal schedule");
+    assert_eq!(schedule.now_ms, 1_250);
+    assert!(std::ptr::eq(schedule.starts, &active));
+}
+
 #[test]
 fn unselected_scene_skips_overlay_stroke() {
     let state = sample_state();