🐛 Evict multi-scale tile cache on shape edits (#11337)

those textures across zoom for progressive previews, and invalidate
by old∪new document coverage so rotate/move edits do not leave
stale fragments on zoom-out.

.serena/memories/render-wasm/ffi-rendering-subtleties.md

@@ -26,7 +26,9 @@
 - During interactive transform, modifier tile invalidation is deferred to `render()` once per rAF. Outside interactive transform, `set_modifiers` rebuilds modifier tiles immediately.
 - `set_modifiers_end` disables fast/interactive state and cancels pending async render; the caller must request the final full-quality render.
 - Plain viewport fast mode (`options.is_viewport_interaction()`) renders from cache and does not flush target output inside `process_animation_frame`; interactive transforms do flush.
-- Zoom changes rebuild the tile index while preserving cached tile textures. Avoid replacing that path with shallow rebuilds if blur/shadow cache preservation matters.
+- Zoom settle wipes the tile texture cache in `set_view_end`. Mid-zoom overlays
+  key tiles by scale; shape edits must `invalidate_cached_tiles_intersecting`
+  the old∪new extrect so those overlays do not keep pre-edit pixels.
 - Pending tile priority is intentionally reversed by pop order; check the queue construction before changing tile scheduling.
 - Frames with a fill may use `render_frame_container_drop_shadow` (direct rrect +
-  blur saveLayer on `DropShadows`) when `uses_direct_container_drop_shadow` is true.
+  blur saveLayer on `DropShadows`) when `uses_direct_container_drop_shadow` is true.

render-wasm/src/render.rs

@@ -383,6 +383,8 @@ pub(crate) struct RenderState {
     /// Frame id passed as `base_object` for viewer renders; always traversed.
     pub viewer_render_root: Option<Uuid>,
     pub touched_ids: HashSet<Uuid>,
+    /// Pre-edit extrects for old∪new tile eviction (captured on first touch).
+    touched_prev_extrects: HashMap<Uuid, Rect>,
     /// Temporary flag used for off-screen passes (drop-shadow masks, filter surfaces, etc.)
     /// where we must render shapes without inheriting ancestor layer blurs. Toggle it through
     /// `with_nested_blurs_suppressed` to ensure it's always restored.
@@ -603,6 +605,7 @@ impl RenderState {
             include_filter: None,
             viewer_render_root: None,
             touched_ids: HashSet::default(),
+            touched_prev_extrects: HashMap::default(),
             ignore_nested_blurs: false,
             preview_mode: false,
             export_context: None,
@@ -1148,6 +1151,8 @@ impl RenderState {
             &tile_rect,
             false,
             self.render_area,
+            self.get_scale(),
+            self.viewbox.area,
         );
 
         Ok(())
@@ -2406,7 +2411,7 @@ impl RenderState {
         performance::begin_measure!("tile_cache");
         let only_visible = self.options.is_interactive_transform();
         self.pending_tiles
-            .update(&self.tile_viewbox, &self.surfaces, only_visible);
+            .update(&self.tile_viewbox, &self.surfaces, scale, only_visible);
         performance::end_measure!("tile_cache");
 
         performance::end_timed_log!("tile_cache_update", _tile_start);
@@ -2498,11 +2503,21 @@ impl RenderState {
             && !self.viewport_presented;
 
         if should_compose {
-            self.surfaces.draw_tile_atlas_to_backbuffer(
+            // Fast mode skips the tile atlas; use the same doc-atlas + scale
-                &self.viewbox,
+            // overlays as render_from_cache instead of composing empty slots.
-                &self.tile_viewbox,
+            if self.options.is_fast_mode() {
-                self.background_color,
+                self.surfaces.draw_combined_atlas_to_backbuffer(
-            );
+                    &self.viewbox,
+                    &self.tile_viewbox,
+                    self.background_color,
+                );
+            } else {
+                self.surfaces.draw_tile_atlas_to_backbuffer(
+                    &self.viewbox,
+                    &self.tile_viewbox,
+                    self.background_color,
+                );
+            }
         }
 
         match frame_type {
@@ -3923,7 +3938,10 @@ impl RenderState {
                 // is not cached because everything will be handled from draw_atlas.
                 // Viewer masked passes (include_filter) must not reuse cached tiles from
                 // a previous pass; otherwise pass-1 pixels can leak into pass 2.
-                if self.viewer_masked_pass() || !self.surfaces.has_cached_tile_surface(current_tile)
+                if self.viewer_masked_pass()
+                    || !self
+                        .surfaces
+                        .has_cached_tile_surface(current_tile, self.get_scale())
                 {
                     performance::begin_measure!("render_shape_tree::uncached");
                     let (is_empty, early_return) = self
@@ -3968,7 +3986,9 @@ impl RenderState {
                         }
                     }
                 } else if self.tiles.is_empty_at(current_tile) {
-                    self.surfaces.remove_cached_tile_surface(current_tile);
+                    // Keep other-scale entries for mid-zoom overlays.
+                    self.surfaces
+                        .remove_cached_tile_surface_at(current_tile, self.get_scale());
                 }
             }
 
@@ -3989,6 +4009,7 @@ impl RenderState {
                 self.drop_shadows_ops_warmed = false;
 
                 let viewer_masked_pass = self.viewer_masked_pass();
+                let current_scale = self.get_scale();
 
                 let Some(ids) = self.tiles.get_shapes_at(next_tile) else {
                     // If the tile is empty we do not need to render it.
@@ -3996,7 +4017,11 @@ impl RenderState {
                 };
 
                 // Never skip based on cached surfaces during viewer masked passes.
-                if !viewer_masked_pass && self.surfaces.has_cached_tile_surface(next_tile) {
+                if !viewer_masked_pass
+                    && self
+                        .surfaces
+                        .has_cached_tile_surface(next_tile, current_scale)
+                {
                     // If the tile is cached, then we do not need to
                     // render it.
                     continue;
@@ -4333,9 +4358,8 @@ impl RenderState {
     pub fn rebuild_touched_tiles(&mut self, tree: ShapesPoolRef) {
         performance::begin_measure!("rebuild_touched_tiles");
 
-        let mut all_tiles = HashSet::<tiles::Tile>::new();
-
         let ids = std::mem::take(&mut self.touched_ids);
+        let prev_extrects = std::mem::take(&mut self.touched_prev_extrects);
         // Pan release sets `preserve_target` in `set_view_end`; don't reset it
         // here when no shapes changed, or the next render clears the canvas.
         if !ids.is_empty() {
@@ -4345,16 +4369,15 @@ impl RenderState {
         for shape_id in ids.iter() {
             if let Some(shape) = tree.get(shape_id) {
                 if shape_id != &Uuid::nil() {
-                    all_tiles.extend(self.update_shape_tiles(shape, tree));
+                    self.invalidate_shape_and_update_tiles(
+                        shape,
+                        tree,
+                        prev_extrects.get(shape_id).copied(),
+                    );
                 }
             }
         }
 
-        // Update the changed tiles
-        for tile in all_tiles {
-            self.remove_cached_tile(tile);
-        }
-
         performance::end_measure!("rebuild_touched_tiles");
     }
 
@@ -4372,19 +4395,50 @@ impl RenderState {
         tree: ShapesPoolMutRef<'_>,
     ) -> Result<()> {
         performance::begin_measure!("invalidate_and_update_tiles");
-        let mut all_tiles = HashSet::<tiles::Tile>::new();
         for shape_id in shape_ids {
             if let Some(shape) = tree.get(shape_id) {
-                all_tiles.extend(self.update_shape_tiles(shape, tree));
+                self.invalidate_shape_and_update_tiles(shape, tree, None);
             }
         }
-        for tile in all_tiles {
-            self.remove_cached_tile(tile);
-        }
         performance::end_measure!("invalidate_and_update_tiles");
         Ok(())
     }
 
+    /// old∪new∪indexed document coverage used to evict cached tiles after edits.
+    fn dirty_doc_rect_for_shape(
+        &mut self,
+        shape: &Shape,
+        tree: ShapesPoolRef,
+        prev_extrect: Option<skia::Rect>,
+    ) -> skia::Rect {
+        let scale = self.get_scale();
+        let new_extrect = self.get_cached_extrect(shape, tree, 1.0);
+        let prev_extrect = prev_extrect.or_else(|| {
+            tree.get_modifier(&shape.id)
+                .and_then(|_| tree.get_raw(&shape.id).map(|raw| raw.extrect(tree, 1.0)))
+        });
+        let indexed = self
+            .tiles
+            .get_tiles_of(shape.id)
+            .into_iter()
+            .flatten()
+            .fold(skia::Rect::new_empty(), |acc, tile| {
+                tiles::join_nonempty(acc, tiles::get_tile_rect(*tile, scale))
+            });
+        tiles::union_edit_dirty_rect(prev_extrect, new_extrect, indexed)
+    }
+
+    fn invalidate_shape_and_update_tiles(
+        &mut self,
+        shape: &Shape,
+        tree: ShapesPoolRef,
+        prev_extrect: Option<skia::Rect>,
+    ) {
+        let dirty = self.dirty_doc_rect_for_shape(shape, tree, prev_extrect);
+        let _ = self.update_shape_tiles(shape, tree);
+        self.surfaces.invalidate_cached_tiles_intersecting(dirty);
+    }
+
     /// Rebuilds tiles for shapes with modifiers and processes their ancestors
     ///
     /// This function applies transformation modifiers to shapes and updates their tiles.
@@ -4423,12 +4477,21 @@ impl RenderState {
     }
 
     pub fn mark_touched(&mut self, uuid: Uuid) {
-        self.touched_ids.insert(uuid);
+        self.mark_touched_with_prev(uuid, None);
+    }
+
+    pub fn mark_touched_with_prev(&mut self, uuid: Uuid, prev_extrect: Option<Rect>) {
+        if self.touched_ids.insert(uuid) {
+            if let Some(rect) = prev_extrect.filter(|r| !r.is_empty()) {
+                self.touched_prev_extrects.insert(uuid, rect);
+            }
+        }
     }
 
     #[allow(dead_code)]
     pub fn clean_touched(&mut self) {
         self.touched_ids.clear();
+        self.touched_prev_extrects.clear();
     }
 
     pub fn get_cached_extrect(&mut self, shape: &Shape, tree: ShapesPoolRef, scale: f32) -> Rect {

render-wasm/src/render/surfaces.rs

@@ -92,6 +92,29 @@ pub enum SurfaceId {
     TileAtlas = 0b100_0000_1000,
 }
 
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
+pub struct TileCacheKey {
+    pub tile: Tile,
+    pub scale_bits: u32,
+}
+
+impl TileCacheKey {
+    pub fn new(tile: Tile, scale: f32) -> Self {
+        Self {
+            tile,
+            scale_bits: scale.to_bits(),
+        }
+    }
+
+    pub fn matches_scale(&self, scale: f32) -> bool {
+        self.scale_bits == scale.to_bits()
+    }
+
+    pub fn scale(&self) -> f32 {
+        f32::from_bits(self.scale_bits)
+    }
+}
+
 pub struct DocAtlas {
     // Persistent 1:1 document-space atlas that gets incrementally updated as tiles render.
     // It grows dynamically to include any rendered document rect.
@@ -105,9 +128,9 @@ pub struct DocAtlas {
     /// Optional document-space bounds (1 unit == 1 doc px @ 100% zoom) used to
     /// clamp atlas writes/clears so the atlas doesn't grow due to outlier tile rects.
     pub doc_bounds: Option<skia::Rect>,
-    /// Tracks the last document-space rect written to the atlas per tile.
+    /// Last atlas write per (tile, scale). Scale is part of the key so zoom
-    /// Used to clear old content without clearing the whole (potentially huge) tile rect.
+    /// levels do not overwrite each other's placement metadata.
-    pub tile_doc_rects: HashMap<Tile, skia::Rect>,
+    pub tile_doc_rects: HashMap<TileCacheKey, skia::Rect>,
 }
 
 impl DocAtlas {
@@ -389,13 +412,17 @@ impl DocAtlas {
         Ok(())
     }
 
-    /// Clears the last atlas region written by `tile` (if any).
+    /// Clears the last atlas region written by `key` (if any).
     ///
     /// This avoids clearing the entire logical tile rect which, at very low
     /// zoom levels, can be enormous in document space and would unnecessarily
     /// grow / rescale the atlas.
-    pub fn clear_tile_in_atlas(&mut self, gpu_state: &mut GpuState, tile: Tile) -> Result<()> {
+    pub fn clear_tile_in_atlas(
-        if let Some(doc_rect) = self.tile_doc_rects.remove(&tile) {
+        &mut self,
+        gpu_state: &mut GpuState,
+        key: TileCacheKey,
+    ) -> Result<()> {
+        if let Some(doc_rect) = self.tile_doc_rects.remove(&key) {
             self.clear_doc_rect_in_atlas(gpu_state, doc_rect)?;
         }
         Ok(())
@@ -1227,6 +1254,7 @@ impl Surfaces {
         canvas.restore();
     }
 
+    #[allow(clippy::too_many_arguments)]
     pub fn draw_current_tile_into_tile_atlas(
         &mut self,
         tile_viewbox: &TileViewbox,
@@ -1234,6 +1262,8 @@ impl Surfaces {
         tile_rect: &skia::Rect,
         skip_cache_surface: bool,
         tile_doc_rect: skia::Rect,
+        scale: f32,
+        view_doc: skia::Rect,
     ) {
         let gpu_state = get_gpu_state();
         let src = skia::Rect::from(TILE_DRAWABLE_RECT);
@@ -1247,9 +1277,14 @@ impl Surfaces {
             tile_doc_rect,
             sampling,
         );
-        self.atlas.tile_doc_rects.insert(*tile, tile_doc_rect);
+        let key = TileCacheKey::new(*tile, scale);
+        self.atlas.tile_doc_rects.insert(key, tile_doc_rect);
 
-        let tile_ref = self.tiles.add(tile_viewbox, tile);
+        let mut tile_doc_rects = std::mem::take(&mut self.atlas.tile_doc_rects);
+        let tile_ref = self
+            .tiles
+            .add(tile_viewbox, tile, scale, view_doc, &mut tile_doc_rects);
+        self.atlas.tile_doc_rects = tile_doc_rects;
         let dst = tile_ref.rect;
         let mut current = self.current.clone();
         draw_surface_src_rect_to_dst(&mut current, self.tile_atlas.canvas(), src, dst, sampling);
@@ -1268,8 +1303,8 @@ impl Surfaces {
         }
     }
 
-    pub fn has_cached_tile_surface(&self, tile: Tile) -> bool {
+    pub fn has_cached_tile_surface(&self, tile: Tile, scale: f32) -> bool {
-        self.tiles.has(tile)
+        self.tiles.has(tile, scale)
     }
 
     /// Builds a 1:1 workspace-pixel snapshot for `src_doc_bounds` / `src_irect` into
@@ -1326,7 +1361,7 @@ impl Surfaces {
                     (clip_doc.bottom - vb_top) * scale - iy0,
                 );
 
-                if let Some(tile_ref) = self.tiles.get(tile) {
+                if let Some(tile_ref) = self.tiles.get(tile, scale) {
                     let bounds = skia::IRect::from_ltrb(
                         tile_ref.rect.left as i32,
                         tile_ref.rect.top as i32,
@@ -1387,7 +1422,47 @@ impl Surfaces {
         self.tiles.remove(tile);
         // Also clear the corresponding region in the persistent atlas to avoid
         // leaving stale pixels when shapes move/delete.
-        let _ = self.atlas.clear_tile_in_atlas(gpu_state, tile);
+        let keys: Vec<_> = self
+            .atlas
+            .tile_doc_rects
+            .keys()
+            .copied()
+            .filter(|key| key.tile == tile)
+            .collect();
+        for key in keys {
+            let _ = self.atlas.clear_tile_in_atlas(gpu_state, key);
+        }
+    }
+
+    /// Drop one (tile, scale) entry; leave other zoom levels alone.
+    pub fn remove_cached_tile_surface_at(&mut self, tile: Tile, scale: f32) {
+        let gpu_state = get_gpu_state();
+        self.tiles.remove_at(tile, scale);
+        let key = TileCacheKey::new(tile, scale);
+        let _ = self.atlas.clear_tile_in_atlas(gpu_state, key);
+    }
+
+    /// Evict every cached tile whose stored doc rect intersects `doc_rect`.
+    pub fn invalidate_cached_tiles_intersecting(&mut self, doc_rect: skia::Rect) {
+        if doc_rect.is_empty() {
+            return;
+        }
+
+        let keys: Vec<TileCacheKey> = self
+            .atlas
+            .tile_doc_rects
+            .iter()
+            .filter_map(|(key, rect)| {
+                (!rect.is_empty() && rect.intersects(doc_rect)).then_some(*key)
+            })
+            .collect();
+
+        let gpu_state = get_gpu_state();
+        for key in keys {
+            self.tiles.remove_at(key.tile, key.scale());
+            let _ = self.atlas.clear_tile_in_atlas(gpu_state, key);
+        }
+        self.atlas.clear_doc_rect_in_atlas_clipped(doc_rect);
     }
 
     /// Draws the current tile directly to the backbuffer and cache surfaces without
@@ -1594,8 +1669,8 @@ pub struct TileTextureCache {
     provider: TileAtlasTextureProvider,
     transforms: Vec<skia::RSXform>,
     textures: Vec<skia::Rect>,
-    grid: HashMap<Tile, TileAtlasTextureRef>,
+    grid: HashMap<TileCacheKey, TileAtlasTextureRef>,
-    removed: HashSet<Tile>,
+    removed: HashSet<TileCacheKey>,
 }
 
 pub struct AtlasDrawBatch {
@@ -1658,9 +1733,10 @@ impl TileTextureCache {
     }
 
     fn gc(&mut self) {
-        // Make a real remove
+        // Drain so soft-deleted keys cannot accumulate forever (scale bits make
-        for tile in self.removed.iter() {
+        // TileCacheKey rarely repeat across zoom levels).
-            if let Some(tile_ref) = self.grid.remove(tile) {
+        for key in self.removed.drain() {
+            if let Some(tile_ref) = self.grid.remove(&key) {
                 self.provider.deallocate(tile_ref);
             }
         }
@@ -1674,29 +1750,57 @@ impl TileTextureCache {
         self.is_updated = false;
     }
 
-    fn gc_non_visible(&mut self, tile_viewbox: &TileViewbox) {
+    fn gc_non_visible(
-        let marked: Vec<_> = self
+        &mut self,
-            .grid
+        tile_viewbox: &TileViewbox,
-            .iter_mut()
+        scale: f32,
-            .filter_map(|(tile, _)| {
+        view_doc: skia::Rect,
-                if !tile_viewbox.is_visible(tile) {
+        tile_doc_rects: &mut HashMap<TileCacheKey, skia::Rect>,
-                    Some(*tile)
+    ) {
-                } else {
+        // Evict by document coverage, not grid index: other-scale tiles can
-                    None
+        // still cover the viewport even when their index is outside visible_rect.
-                }
+        let mut offscreen = Vec::new();
-            })
+        let mut other_scale_onscreen = Vec::new();
-            .take(TEXTURES_BATCH_DELETE)
-            .collect();
 
-        for tile in marked.iter() {
+        for key in self.grid.keys() {
-            if let Some(tile_ref) = self.grid.remove(tile) {
+            if self.removed.contains(key) {
+                continue;
+            }
+            if key.matches_scale(scale) && tile_viewbox.is_visible(&key.tile) {
+                continue;
+            }
+
+            let intersects = tile_doc_rects
+                .get(key)
+                .is_some_and(|doc_rect| !doc_rect.is_empty() && doc_rect.intersects(view_doc));
+
+            if intersects {
+                if !key.matches_scale(scale) {
+                    other_scale_onscreen.push(*key);
+                }
+            } else {
+                offscreen.push(*key);
+            }
+        }
+
+        let mut marked = Vec::with_capacity(TEXTURES_BATCH_DELETE);
+        marked.extend(offscreen.into_iter().take(TEXTURES_BATCH_DELETE));
+        if marked.len() < TEXTURES_BATCH_DELETE {
+            let remaining = TEXTURES_BATCH_DELETE - marked.len();
+            marked.extend(other_scale_onscreen.into_iter().take(remaining));
+        }
+
+        for key in marked.iter() {
+            if let Some(tile_ref) = self.grid.remove(key) {
                 self.provider.deallocate(tile_ref);
             }
+            tile_doc_rects.remove(key);
         }
     }
 
     pub fn update(&mut self, viewbox: &Viewbox, tile_viewbox: &TileViewbox) {
         let dest_scale = self.dest_scale();
+        let scale = viewbox.get_scale();
         if self.transforms.len() != tile_viewbox.visible_rect.len() as usize {
             self.transforms.resize(
                 tile_viewbox.visible_rect.len() as usize,
@@ -1719,13 +1823,13 @@ impl TileTextureCache {
         let mut index = 0;
         for y in tile_viewbox.visible_rect.top()..=tile_viewbox.visible_rect.bottom() {
             for x in tile_viewbox.visible_rect.left()..=tile_viewbox.visible_rect.right() {
-                let tile = Tile(x, y);
+                let key = TileCacheKey::new(Tile(x, y), scale);
 
-                let Some(tile_ref) = self.grid.get(&tile) else {
+                let Some(tile_ref) = self.grid.get(&key) else {
                     continue;
                 };
 
-                if self.removed.contains(&tile) {
+                if self.removed.contains(&key) {
                     continue;
                 }
 
@@ -1750,7 +1854,7 @@ impl TileTextureCache {
         &self,
         viewbox: &Viewbox,
         tile_viewbox: &TileViewbox,
-        tile_doc_rects: &HashMap<Tile, skia::Rect>,
+        tile_doc_rects: &HashMap<TileCacheKey, skia::Rect>,
     ) -> AtlasDrawBatch {
         let mut transforms = Vec::new();
         let mut textures = Vec::new();
@@ -1760,20 +1864,20 @@ impl TileTextureCache {
 
         for y in tile_viewbox.visible_rect.top()..=tile_viewbox.visible_rect.bottom() {
             for x in tile_viewbox.visible_rect.left()..=tile_viewbox.visible_rect.right() {
-                let tile = Tile(x, y);
+                let key = TileCacheKey::new(Tile(x, y), s);
 
-                let Some(tile_ref) = self.grid.get(&tile) else {
+                let Some(tile_ref) = self.grid.get(&key) else {
                     continue;
                 };
 
-                if self.removed.contains(&tile) {
+                if self.removed.contains(&key) {
                     continue;
                 }
 
                 let doc_rect = tile_doc_rects
-                    .get(&tile)
+                    .get(&key)
                     .copied()
-                    .unwrap_or_else(|| tiles::get_tile_rect(tile, s));
+                    .unwrap_or_else(|| tiles::get_tile_rect(key.tile, s));
                 if doc_rect.is_empty() || !doc_rect.intersects(view_doc) {
                     continue;
                 }
@@ -1788,17 +1892,22 @@ impl TileTextureCache {
             }
         }
 
-        // Cached tiles from a previous zoom level use indices outside visible_rect;
+        // Other-scale / off-grid tiles: place via stored doc rect (not current scale).
-        // place them via their stored document rect, not the current grid walk above.
+        for (&key, tile_ref) in &self.grid {
-        for (&tile, tile_ref) in &self.grid {
+            if self.removed.contains(&key) {
-            if tile_viewbox.is_visible(&tile) || self.removed.contains(&tile) {
+                continue;
+            }
+            let visible = tile_viewbox.is_visible(&key.tile);
+            if key.matches_scale(s) && visible {
+                continue;
+            }
+            if !key.matches_scale(s) && visible && self.has(key.tile, s) {
                 continue;
             }
 
-            let doc_rect = tile_doc_rects
+            let Some(doc_rect) = tile_doc_rects.get(&key).copied() else {
-                .get(&tile)
+                continue;
-                .copied()
+            };
-                .unwrap_or_else(|| tiles::get_tile_rect(tile, s));
             if doc_rect.is_empty() || !doc_rect.intersects(view_doc) {
                 continue;
             }
@@ -1818,11 +1927,19 @@ impl TileTextureCache {
         }
     }
 
-    pub fn has(&self, tile: Tile) -> bool {
+    pub fn has(&self, tile: Tile, scale: f32) -> bool {
-        self.grid.contains_key(&tile) && !self.removed.contains(&tile)
+        let key = TileCacheKey::new(tile, scale);
+        self.grid.contains_key(&key) && !self.removed.contains(&key)
     }
 
-    pub fn add(&mut self, tile_viewbox: &TileViewbox, tile: &Tile) -> TileAtlasTextureRef {
+    pub fn add(
+        &mut self,
+        tile_viewbox: &TileViewbox,
+        tile: &Tile,
+        scale: f32,
+        view_doc: skia::Rect,
+        tile_doc_rects: &mut HashMap<TileCacheKey, skia::Rect>,
+    ) -> TileAtlasTextureRef {
         // Evict against the real slot count (`provider.length`), not the
         // hardcoded capacity — otherwise the guard never fires and the atlas
         // fills up until `allocate()` has no slot left.
@@ -1830,41 +1947,67 @@ impl TileTextureCache {
 
         if self.grid.len() >= capacity {
             self.gc();
-            self.gc_non_visible(tile_viewbox);
+            self.gc_non_visible(tile_viewbox, scale, view_doc, tile_doc_rects);
         }
 
         let Some(tile_ref) = self.provider.allocate() else {
             panic!("Tile texture allocation failed {}:{}", tile.0, tile.1);
         };
-        self.insert(tile, tile_ref)
+        self.insert(TileCacheKey::new(*tile, scale), tile_ref)
     }
 
-    fn insert(&mut self, tile: &Tile, tile_ref: TileAtlasTextureRef) -> TileAtlasTextureRef {
+    fn insert(&mut self, key: TileCacheKey, tile_ref: TileAtlasTextureRef) -> TileAtlasTextureRef {
-        self.grid.insert(*tile, tile_ref.clone());
+        if let Some(old_ref) = self.grid.insert(key, tile_ref.clone()) {
+            self.provider.deallocate(old_ref);
+        }
 
-        if self.removed.contains(tile) {
+        if self.removed.contains(&key) {
-            self.removed.remove(tile);
+            self.removed.remove(&key);
         }
 
         self.is_updated = true;
         tile_ref
     }
 
-    pub fn get(&mut self, tile: Tile) -> Option<&TileAtlasTextureRef> {
+    pub fn get(&mut self, tile: Tile, scale: f32) -> Option<&TileAtlasTextureRef> {
-        if self.removed.contains(&tile) {
+        let key = TileCacheKey::new(tile, scale);
+        if self.removed.contains(&key) {
             return None;
         }
-        self.grid.get(&tile)
+        self.grid.get(&key)
     }
 
     pub fn remove(&mut self, tile: Tile) {
-        if let Some(tile_ref) = self.grid.get(&tile) {
+        let keys: Vec<_> = self
-            if tile_ref.index < self.textures.len() {
+            .grid
-                self.textures[tile_ref.index].set_empty();
+            .keys()
+            .copied()
+            .filter(|key| key.tile == tile)
+            .collect();
+        if keys.is_empty() {
+            return;
+        }
+        for key in keys {
+            if let Some(tile_ref) = self.grid.get(&key) {
+                if tile_ref.index < self.textures.len() {
+                    self.textures[tile_ref.index].set_empty();
+                }
             }
+            self.removed.insert(key);
         }
         self.is_updated = true;
-        self.removed.insert(tile);
+    }
+
+    pub fn remove_at(&mut self, tile: Tile, scale: f32) {
+        let key = TileCacheKey::new(tile, scale);
+        let Some(tile_ref) = self.grid.get(&key) else {
+            return;
+        };
+        if tile_ref.index < self.textures.len() {
+            self.textures[tile_ref.index].set_empty();
+        }
+        self.removed.insert(key);
+        self.is_updated = true;
     }
 
     pub fn clear(&mut self) {

render-wasm/src/state.rs

@@ -198,22 +198,24 @@ impl State {
             // headless export path has none, so skip it there.
             if has_render_state() {
                 let render_state = get_render_state();
-                // IMPORTANT:
+                // Do NOT use `get_tiles_for_shape` (interest-clipped). Evict by
-                // Do NOT use `get_tiles_for_shape` here. That method intersects the shape
+                // document coverage so cached tiles outside the interest area
-                // tiles with the current interest area, which means we'd only invalidate
+                // cannot keep pixels of the deleted shape.
-                // the subset currently near the viewport. When the user later pans/zooms
-                // to reveal previously cached tiles, stale pixels could reappear.
-                //
-                // Instead, remove the shape from *all* tiles where it was indexed, and
-                // drop cached tiles for those entries.
                 let indexed_tiles: Vec<tiles::Tile> = render_state
                     .tiles
                     .get_tiles_of(shape.id)
                     .map(|t| t.iter().copied().collect())
                     .unwrap_or_default();
-
+                let scale = render_state.get_scale();
+                let dirty = indexed_tiles
+                    .iter()
+                    .fold(shape.extrect(&self.shapes, 1.0), |acc, tile| {
+                        tiles::join_nonempty(acc, tiles::get_tile_rect(*tile, scale))
+                    });
+                render_state
+                    .surfaces
+                    .invalidate_cached_tiles_intersecting(dirty);
                 for tile in indexed_tiles {
-                    render_state.remove_cached_tile(tile);
                     render_state.tiles.remove_shape_at(tile, shape.id);
                 }
             }
@@ -345,7 +347,11 @@ impl State {
             return;
         }
         if let Some(current_id) = self.current_id {
-            get_render_state().mark_touched(current_id);
+            let prev = self
+                .shapes
+                .get(&current_id)
+                .map(|shape| shape.extrect(&self.shapes, 1.0));
+            get_render_state().mark_touched_with_prev(current_id, prev);
         }
     }
 
@@ -353,6 +359,10 @@ impl State {
         if self.loading || !has_render_state() {
             return;
         }
-        get_render_state().mark_touched(id);
+        let prev = self
+            .shapes
+            .get(&id)
+            .map(|shape| shape.extrect(&self.shapes, 1.0));
+        get_render_state().mark_touched_with_prev(id, prev);
     }
 }

render-wasm/src/tiles.rs

@@ -370,7 +370,13 @@ impl PendingTiles {
         }
     }
 
-    pub fn update(&mut self, tile_viewbox: &TileViewbox, surfaces: &Surfaces, only_visible: bool) {
+    pub fn update(
+        &mut self,
+        tile_viewbox: &TileViewbox,
+        surfaces: &Surfaces,
+        scale: f32,
+        only_visible: bool,
+    ) {
         self.list.clear();
         self.deferred_interest.clear();
 
@@ -417,7 +423,7 @@ impl PendingTiles {
         for (_, tile) in self.tile_order.iter() {
             let tile = *tile;
             let is_visible = tile_viewbox.visible_rect.contains(&tile);
-            let is_cached = surfaces.has_cached_tile_surface(tile);
+            let is_cached = surfaces.has_cached_tile_surface(tile, scale);
 
             match (is_visible, is_cached) {
                 (true, true) => self.visible_cached.push(tile),
@@ -456,9 +462,34 @@ impl PendingTiles {
     }
 }
 
+pub fn join_nonempty(mut acc: skia::Rect, rect: skia::Rect) -> skia::Rect {
+    if rect.is_empty() {
+        return acc;
+    }
+    if acc.is_empty() {
+        rect
+    } else {
+        acc.join(rect);
+        acc
+    }
+}
+
+/// old ∪ new ∪ indexed tile coverage for post-edit cache eviction.
+pub fn union_edit_dirty_rect(
+    old: Option<skia::Rect>,
+    new: skia::Rect,
+    indexed: skia::Rect,
+) -> skia::Rect {
+    [old, Some(new), Some(indexed)]
+        .into_iter()
+        .flatten()
+        .fold(skia::Rect::new_empty(), join_nonempty)
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
+    use skia_safe as skia;
 
     #[test]
     fn atlas_slot_is_full_size_when_tiles_fit() {
@@ -487,4 +518,22 @@ mod tests {
         assert!((scale * src - TILE_SIZE).abs() < 1e-4);
         assert!(src < slot as f32);
     }
+
+    #[test]
+    fn edit_dirty_rect_includes_pre_rotate_extent_outside_current_index() {
+        // Indexed tiles are interest-clipped; old AABB still covers wings.
+        let old = skia::Rect::from_ltrb(-1103.0, 1871.1, 4693.2, 3559.9);
+        let new = skia::Rect::from_ltrb(1445.0, -164.4, 2144.9, 5598.0);
+        let indexed = skia::Rect::from_ltrb(663.1, 1989.4, 2652.6, 3315.7);
+        let left_wing = skia::Rect::from_ltrb(-3926.0, 0.0, 0.0, 3926.0);
+        let right_wing = skia::Rect::from_ltrb(3926.0, 0.0, 7852.0, 3926.0);
+
+        let without_old = union_edit_dirty_rect(None, new, indexed);
+        assert!(!without_old.intersects(left_wing));
+        assert!(!without_old.intersects(right_wing));
+
+        let dirty = union_edit_dirty_rect(Some(old), new, indexed);
+        assert!(dirty.intersects(left_wing));
+        assert!(dirty.intersects(right_wing));
+    }
 }