WIP

render-wasm/src/main.rs

@@ -258,10 +258,12 @@ pub extern "C" fn set_view_end() {
     with_state_mut!(state, {
         let _end_start = performance::begin_timed_log!("set_view_end");
         performance::begin_measure!("set_view_end");
+
         state.render_state.options.set_fast_mode(false);
         state.render_state.cancel_animation_frame();
 
         let zoom_changed = state.render_state.zoom_changed();
+
         // Only rebuild tile indices when zoom has changed.
         // During pan-only operations, shapes stay in the same tiles
         // because tile_size = 1/scale * TILE_SIZE (depends only on zoom).
@@ -284,6 +286,10 @@ pub extern "C" fn set_view_end() {
             performance::end_measure!("set_view_end::clear_tile_index");
             performance::end_timed_log!("clear_tile_index", _clear_start);
         }
+        // Sync cached_viewbox with current viewbox to ensure accurate
+        // comparison in subsequent calls, especially during rapid zoom+pan
+        // interactions where multiple set_view calls occur before set_view_end.
+        // state.render_state.sync_cached_viewbox();
         performance::end_measure!("set_view_end");
         performance::end_timed_log!("set_view_end", _end_start);
         #[cfg(feature = "profile-macros")]

render-wasm/src/render.rs

@@ -1136,6 +1136,23 @@ impl RenderState {
     ) -> Result<(), String> {
         let _start = performance::begin_timed_log!("start_render_loop");
         let scale = self.get_scale();
+        let zoom_changed = self.zoom_changed();
+        // CRITICAL FIX: If zoom changed, we MUST rebuild the tile index before using it.
+        // Otherwise, the index will have tiles from the old zoom level, causing visible
+        // tiles to appear empty. This can happen if start_render_loop() is called before
+        // set_view_end() finishes rebuilding the index, or if set_view_end() hasn't been
+        // called yet. We have access to tree here, so we can rebuild the index ourselves.
+        //
+        // IMPORTANT: If there's a render in progress, we must cancel it first because
+        // rebuild_tiles_shallow() will invalidate the tile index, causing tiles already
+        // in pending_tiles to lose their shapes.
+        if zoom_changed {
+            if self.render_in_progress {
+                self.cancel_animation_frame();
+            }
+            self.rebuild_tiles_shallow(tree);
+        }
+
         self.tile_viewbox.update(self.viewbox, scale);
 
         self.focus_mode.reset();
@@ -1988,7 +2005,6 @@ impl RenderState {
                         self.background_color,
                     );
                     performance::end_measure!("render_shape_tree::cached");
-
                     if self.options.is_debug_visible() {
                         debug::render_workspace_current_tile(
                             self,
@@ -2001,7 +2017,6 @@ impl RenderState {
                     performance::begin_measure!("render_shape_tree::uncached");
                     let (is_empty, early_return) =
                         self.render_shape_tree_partial_uncached(tree, timestamp, allow_stop)?;
-
                     if early_return {
                         return Ok(());
                     }
@@ -2027,7 +2042,6 @@ impl RenderState {
                     }
                 }
             }
-
             self.surfaces
                 .canvas(SurfaceId::Current)
                 .clear(self.background_color);
@@ -2066,19 +2080,14 @@ impl RenderState {
         self.render_in_progress = false;
 
         self.surfaces.gc();
-
         // Cache target surface in a texture
         self.cached_viewbox = self.viewbox;
-
         self.cached_target_snapshot = Some(self.surfaces.snapshot(SurfaceId::Cache));
-
         if self.options.is_debug_visible() {
             debug::render(self);
         }
-
         ui::render(self, tree);
         debug::render_wasm_label(self);
-
         Ok(())
     }
 
@@ -2162,13 +2171,11 @@ impl RenderState {
                 }
             }
         }
-
         // Update the changed tiles
         self.surfaces.remove_cached_tiles(self.background_color);
         for tile in all_tiles {
             self.remove_cached_tile(tile);
         }
-
         performance::end_measure!("rebuild_tiles_shallow");
     }
 
@@ -2292,6 +2299,13 @@ impl RenderState {
         (self.viewbox.zoom - self.cached_viewbox.zoom).abs() > f32::EPSILON
     }
 
+    /// Updates the cached viewbox to match the current viewbox.
+    /// This should be called at the end of view interactions to ensure
+    /// that cached_viewbox reflects the most recent state for the next comparison.
+    pub fn sync_cached_viewbox(&mut self) {
+        self.cached_viewbox = self.viewbox;
+    }
+
     pub fn mark_touched(&mut self, uuid: Uuid) {
         self.touched_ids.insert(uuid);
     }