feat(editor): improve edgeless perf & memory usage (#14591)

#### PR Dependency Tree


* **PR #14591** 👈

This tree was auto-generated by
[Charcoal](https://github.com/danerwilliams/charcoal)

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit

* **New Features**
* New canvas renderer debug metrics and controls for runtime inspection.
* Mindmap/group reordering now normalizes group targets, improving
reorder consistency.

* **Bug Fixes**
  * Fixed connector behavior for empty/degenerate paths.
* More aggressive viewport invalidation so structural changes display
correctly.
* Improved z-index synchronization during transforms and layer updates.

* **Performance**
* Retained DOM caching for brushes, shapes, and connectors to reduce DOM
churn.
* Targeted canvas refreshes, pooling, and reuse to lower redraw and
memory overhead.

* **Tests**
* Added canvas renderer performance benchmarks and curve edge-case unit
tests.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

blocksuite/affine/blocks/root/src/edgeless/configs/toolbar/more.ts

@@ -22,6 +22,7 @@ import {
   FrameBlockModel,
   ImageBlockModel,
   isExternalEmbedModel,
+  MindmapElementModel,
   NoteBlockModel,
   ParagraphBlockModel,
 } from '@blocksuite/affine-model';
@@ -401,7 +402,17 @@ function reorderElements(
 ) {
   if (!models.length) return;
 
-  for (const model of models) {
+  const normalizedModels = Array.from(
+    new Map(
+      models.map(model => {
+        const reorderTarget =
+          model.group instanceof MindmapElementModel ? model.group : model;
+        return [reorderTarget.id, reorderTarget];
+      })
+    ).values()
+  );
+
+  for (const model of normalizedModels) {
     const index = ctx.gfx.layer.getReorderedIndex(model, type);
 
     // block should be updated in transaction

blocksuite/affine/blocks/surface/src/renderer/canvas-renderer.ts

@@ -2,16 +2,24 @@ import { type Color, ColorScheme } from '@blocksuite/affine-model';
 import { FeatureFlagService } from '@blocksuite/affine-shared/services';
 import { requestConnectedFrame } from '@blocksuite/affine-shared/utils';
 import { DisposableGroup } from '@blocksuite/global/disposable';
-import type { IBound } from '@blocksuite/global/gfx';
-import { getBoundWithRotation, intersects } from '@blocksuite/global/gfx';
+import {
+  Bound,
+  getBoundWithRotation,
+  type IBound,
+  intersects,
+} from '@blocksuite/global/gfx';
 import type { BlockStdScope } from '@blocksuite/std';
 import type {
   GfxCompatibleInterface,
+  GfxController,
+  GfxLocalElementModel,
   GridManager,
   LayerManager,
   SurfaceBlockModel,
   Viewport,
 } from '@blocksuite/std/gfx';
+import { GfxControllerIdentifier } from '@blocksuite/std/gfx';
+import { effect } from '@preact/signals-core';
 import last from 'lodash-es/last';
 import { Subject } from 'rxjs';
 
@@ -40,11 +48,82 @@ type RendererOptions = {
   surfaceModel: SurfaceBlockModel;
 };
 
+export type CanvasRenderPassMetrics = {
+  overlayCount: number;
+  placeholderElementCount: number;
+  renderByBoundCallCount: number;
+  renderedElementCount: number;
+  visibleElementCount: number;
+};
+
+export type CanvasMemorySnapshot = {
+  bytes: number;
+  datasetLayerId: string | null;
+  height: number;
+  kind: 'main' | 'stacking';
+  width: number;
+  zIndex: string;
+};
+
+export type CanvasRendererDebugMetrics = {
+  canvasLayerCount: number;
+  canvasMemoryBytes: number;
+  canvasMemorySnapshots: CanvasMemorySnapshot[];
+  canvasMemoryMegabytes: number;
+  canvasPixelCount: number;
+  coalescedRefreshCount: number;
+  dirtyLayerRenderCount: number;
+  fallbackElementCount: number;
+  lastRenderDurationMs: number;
+  lastRenderMetrics: CanvasRenderPassMetrics;
+  maxRenderDurationMs: number;
+  pooledStackingCanvasCount: number;
+  refreshCount: number;
+  renderCount: number;
+  stackingCanvasCount: number;
+  totalLayerCount: number;
+  totalRenderDurationMs: number;
+  visibleStackingCanvasCount: number;
+};
+
+type MutableCanvasRendererDebugMetrics = Omit<
+  CanvasRendererDebugMetrics,
+  | 'canvasLayerCount'
+  | 'canvasMemoryBytes'
+  | 'canvasMemoryMegabytes'
+  | 'canvasPixelCount'
+  | 'canvasMemorySnapshots'
+  | 'pooledStackingCanvasCount'
+  | 'stackingCanvasCount'
+  | 'totalLayerCount'
+  | 'visibleStackingCanvasCount'
+>;
+
+type RenderPassStats = CanvasRenderPassMetrics;
+
+type StackingCanvasState = {
+  bound: Bound | null;
+  layerId: string | null;
+};
+
+type RefreshTarget =
+  | { type: 'all' }
+  | { type: 'main' }
+  | { type: 'element'; element: SurfaceElementModel | GfxLocalElementModel }
+  | {
+      type: 'elements';
+      elements: Array<SurfaceElementModel | GfxLocalElementModel>;
+    };
+
+const STACKING_CANVAS_PADDING = 32;
+
 export class CanvasRenderer {
   private _container!: HTMLElement;
 
   private readonly _disposables = new DisposableGroup();
 
+  private readonly _gfx: GfxController;
+
   private readonly _turboEnabled: () => boolean;
 
   private readonly _overlays = new Set<Overlay>();
@@ -53,6 +132,37 @@ export class CanvasRenderer {
 
   private _stackingCanvas: HTMLCanvasElement[] = [];
 
+  private readonly _stackingCanvasPool: HTMLCanvasElement[] = [];
+
+  private readonly _stackingCanvasState = new WeakMap<
+    HTMLCanvasElement,
+    StackingCanvasState
+  >();
+
+  private readonly _dirtyStackingCanvasIndexes = new Set<number>();
+
+  private _mainCanvasDirty = true;
+
+  private _needsFullRender = true;
+
+  private _debugMetrics: MutableCanvasRendererDebugMetrics = {
+    refreshCount: 0,
+    coalescedRefreshCount: 0,
+    renderCount: 0,
+    totalRenderDurationMs: 0,
+    lastRenderDurationMs: 0,
+    maxRenderDurationMs: 0,
+    lastRenderMetrics: {
+      renderByBoundCallCount: 0,
+      visibleElementCount: 0,
+      renderedElementCount: 0,
+      placeholderElementCount: 0,
+      overlayCount: 0,
+    },
+    dirtyLayerRenderCount: 0,
+    fallbackElementCount: 0,
+  };
+
   canvas: HTMLCanvasElement;
 
   ctx: CanvasRenderingContext2D;
@@ -89,6 +199,7 @@ export class CanvasRenderer {
     this.layerManager = options.layerManager;
     this.grid = options.gridManager;
     this.provider = options.provider ?? {};
+    this._gfx = this.std.get(GfxControllerIdentifier);
 
     this._turboEnabled = () => {
       const featureFlagService = options.std.get(FeatureFlagService);
@@ -132,15 +243,199 @@ export class CanvasRenderer {
     };
   }
 
+  private _applyStackingCanvasLayout(
+    canvas: HTMLCanvasElement,
+    bound: Bound | null,
+    dpr = window.devicePixelRatio
+  ) {
+    const state =
+      this._stackingCanvasState.get(canvas) ??
+      ({
+        bound: null,
+        layerId: canvas.dataset.layerId ?? null,
+      } satisfies StackingCanvasState);
+
+    if (!bound || bound.w <= 0 || bound.h <= 0) {
+      canvas.style.display = 'none';
+      canvas.style.left = '0px';
+      canvas.style.top = '0px';
+      canvas.style.width = '0px';
+      canvas.style.height = '0px';
+      canvas.style.transform = '';
+      canvas.width = 0;
+      canvas.height = 0;
+      state.bound = null;
+      state.layerId = canvas.dataset.layerId ?? null;
+      this._stackingCanvasState.set(canvas, state);
+      return;
+    }
+
+    const { viewportBounds, zoom, viewScale } = this.viewport;
+    const width = bound.w * zoom;
+    const height = bound.h * zoom;
+    const left = (bound.x - viewportBounds.x) * zoom;
+    const top = (bound.y - viewportBounds.y) * zoom;
+    const actualWidth = Math.max(1, Math.ceil(width * dpr));
+    const actualHeight = Math.max(1, Math.ceil(height * dpr));
+    const transform = `translate(${left}px, ${top}px) scale(${1 / viewScale})`;
+
+    if (canvas.style.display !== 'block') {
+      canvas.style.display = 'block';
+    }
+    if (canvas.style.left !== '0px') {
+      canvas.style.left = '0px';
+    }
+    if (canvas.style.top !== '0px') {
+      canvas.style.top = '0px';
+    }
+    if (canvas.style.width !== `${width}px`) {
+      canvas.style.width = `${width}px`;
+    }
+    if (canvas.style.height !== `${height}px`) {
+      canvas.style.height = `${height}px`;
+    }
+    if (canvas.style.transform !== transform) {
+      canvas.style.transform = transform;
+    }
+    if (canvas.style.transformOrigin !== 'top left') {
+      canvas.style.transformOrigin = 'top left';
+    }
+
+    if (canvas.width !== actualWidth) {
+      canvas.width = actualWidth;
+    }
+
+    if (canvas.height !== actualHeight) {
+      canvas.height = actualHeight;
+    }
+
+    state.bound = bound;
+    state.layerId = canvas.dataset.layerId ?? null;
+    this._stackingCanvasState.set(canvas, state);
+  }
+
+  private _clampBoundToViewport(bound: Bound, viewportBounds: Bound) {
+    const minX = Math.max(bound.x, viewportBounds.x);
+    const minY = Math.max(bound.y, viewportBounds.y);
+    const maxX = Math.min(bound.maxX, viewportBounds.maxX);
+    const maxY = Math.min(bound.maxY, viewportBounds.maxY);
+
+    if (maxX <= minX || maxY <= minY) {
+      return null;
+    }
+
+    return new Bound(minX, minY, maxX - minX, maxY - minY);
+  }
+
+  private _createCanvasForLayer(
+    onCreated?: (canvas: HTMLCanvasElement) => void
+  ) {
+    const reused = this._stackingCanvasPool.pop();
+
+    if (reused) {
+      return reused;
+    }
+
+    const created = document.createElement('canvas');
+    onCreated?.(created);
+    return created;
+  }
+
+  private _findLayerIndexByElement(
+    element: SurfaceElementModel | GfxLocalElementModel
+  ) {
+    const canvasLayers = this.layerManager.getCanvasLayers();
+    const index = canvasLayers.findIndex(layer =>
+      layer.elements.some(layerElement => layerElement.id === element.id)
+    );
+
+    return index === -1 ? null : index;
+  }
+
+  private _getLayerRenderBound(
+    elements: SurfaceElementModel[],
+    viewportBounds: Bound
+  ) {
+    let layerBound: Bound | null = null;
+
+    for (const element of elements) {
+      const display = (element.display ?? true) && !element.hidden;
+
+      if (!display) {
+        continue;
+      }
+
+      const elementBound = Bound.from(getBoundWithRotation(element));
+
+      if (!intersects(elementBound, viewportBounds)) {
+        continue;
+      }
+
+      layerBound = layerBound ? layerBound.unite(elementBound) : elementBound;
+    }
+
+    if (!layerBound) {
+      return null;
+    }
+
+    return this._clampBoundToViewport(
+      layerBound.expand(STACKING_CANVAS_PADDING),
+      viewportBounds
+    );
+  }
+
+  private _getResolvedStackingCanvasBound(
+    canvas: HTMLCanvasElement,
+    bound: Bound | null
+  ) {
+    if (!bound || !this._gfx.tool.dragging$.peek()) {
+      return bound;
+    }
+
+    const previousBound = this._stackingCanvasState.get(canvas)?.bound;
+
+    return previousBound ? previousBound.unite(bound) : bound;
+  }
+
+  private _invalidate(target: RefreshTarget = { type: 'all' }) {
+    if (target.type === 'all') {
+      this._needsFullRender = true;
+      this._mainCanvasDirty = true;
+      this._dirtyStackingCanvasIndexes.clear();
+      return;
+    }
+
+    if (this._needsFullRender) {
+      return;
+    }
+
+    if (target.type === 'main') {
+      this._mainCanvasDirty = true;
+      return;
+    }
+
+    const elements =
+      target.type === 'element' ? [target.element] : target.elements;
+
+    for (const element of elements) {
+      const layerIndex = this._findLayerIndexByElement(element);
+
+      if (layerIndex === null || layerIndex >= this._stackingCanvas.length) {
+        this._mainCanvasDirty = true;
+        continue;
+      }
+
+      this._dirtyStackingCanvasIndexes.add(layerIndex);
+    }
+  }
+
+  private _resetPooledCanvas(canvas: HTMLCanvasElement) {
+    canvas.dataset.layerId = '';
+    this._applyStackingCanvasLayout(canvas, null);
+  }
+
   private _initStackingCanvas(onCreated?: (canvas: HTMLCanvasElement) => void) {
     const layer = this.layerManager;
-    const updateStackingCanvasSize = (canvases: HTMLCanvasElement[]) => {
-      this._stackingCanvas = canvases;
-
-      const sizeUpdater = this._canvasSizeUpdater();
-
-      canvases.filter(sizeUpdater.filter).forEach(sizeUpdater.update);
-    };
     const updateStackingCanvas = () => {
       /**
        * we already have a main canvas, so the last layer should be skipped
@@ -159,11 +454,7 @@ export class CanvasRenderer {
         const created = i < currentCanvases.length;
         const canvas = created
           ? currentCanvases[i]
-          : document.createElement('canvas');
-
-        if (!created) {
-          onCreated?.(canvas);
-        }
+          : this._createCanvasForLayer(onCreated);
 
         canvas.dataset.layerId = `[${layer.indexes[0]}--${layer.indexes[1]}]`;
         canvas.style.zIndex = layer.zIndex.toString();
@@ -171,7 +462,6 @@ export class CanvasRenderer {
       }
 
       this._stackingCanvas = canvases;
-      updateStackingCanvasSize(canvases);
 
       if (currentCanvases.length !== canvases.length) {
         const diff = canvases.length - currentCanvases.length;
@@ -189,12 +479,16 @@ export class CanvasRenderer {
           payload.added = canvases.slice(-diff);
         } else {
           payload.removed = currentCanvases.slice(diff);
+          payload.removed.forEach(canvas => {
+            this._resetPooledCanvas(canvas);
+            this._stackingCanvasPool.push(canvas);
+          });
         }
 
         this.stackingCanvasUpdated.next(payload);
       }
 
-      this.refresh();
+      this.refresh({ type: 'all' });
     };
 
     this._disposables.add(
@@ -211,7 +505,7 @@ export class CanvasRenderer {
 
     this._disposables.add(
       this.viewport.viewportUpdated.subscribe(() => {
-        this.refresh();
+        this.refresh({ type: 'all' });
       })
     );
 
@@ -222,7 +516,6 @@ export class CanvasRenderer {
           sizeUpdatedRafId = null;
           this._resetSize();
           this._render();
-          this.refresh();
         }, this._container);
       })
     );
@@ -233,69 +526,212 @@ export class CanvasRenderer {
 
         if (this.usePlaceholder !== shouldRenderPlaceholders) {
           this.usePlaceholder = shouldRenderPlaceholders;
-          this.refresh();
+          this.refresh({ type: 'all' });
         }
       })
     );
 
+    let wasDragging = false;
+    this._disposables.add(
+      effect(() => {
+        const isDragging = this._gfx.tool.dragging$.value;
+
+        if (wasDragging && !isDragging) {
+          this.refresh({ type: 'all' });
+        }
+
+        wasDragging = isDragging;
+      })
+    );
+
     this.usePlaceholder = false;
   }
 
+  private _createRenderPassStats(): RenderPassStats {
+    return {
+      renderByBoundCallCount: 0,
+      visibleElementCount: 0,
+      renderedElementCount: 0,
+      placeholderElementCount: 0,
+      overlayCount: 0,
+    };
+  }
+
+  private _getCanvasMemorySnapshots(): CanvasMemorySnapshot[] {
+    return [this.canvas, ...this._stackingCanvas].map((canvas, index) => {
+      return {
+        kind: index === 0 ? 'main' : 'stacking',
+        width: canvas.width,
+        height: canvas.height,
+        bytes: canvas.width * canvas.height * 4,
+        zIndex: canvas.style.zIndex,
+        datasetLayerId: canvas.dataset.layerId ?? null,
+      };
+    });
+  }
+
   private _render() {
+    const renderStart = performance.now();
     const { viewportBounds, zoom } = this.viewport;
     const { ctx } = this;
     const dpr = window.devicePixelRatio;
     const scale = zoom * dpr;
     const matrix = new DOMMatrix().scaleSelf(scale);
+    const renderStats = this._createRenderPassStats();
+    const fullRender = this._needsFullRender;
+    const stackingIndexesToRender = fullRender
+      ? this._stackingCanvas.map((_, idx) => idx)
+      : [...this._dirtyStackingCanvasIndexes];
     /**
      * if a layer does not have a corresponding canvas
      * its element will be add to this array and drawing on the
      * main canvas
      */
     let fallbackElement: SurfaceElementModel[] = [];
+    const allCanvasLayers = this.layerManager.getCanvasLayers();
+    const viewportBound = Bound.from(viewportBounds);
 
-    this.layerManager.getCanvasLayers().forEach((layer, idx) => {
-      if (!this._stackingCanvas[idx]) {
-        fallbackElement = fallbackElement.concat(layer.elements);
-        return;
+    for (const idx of stackingIndexesToRender) {
+      const layer = allCanvasLayers[idx];
+      const canvas = this._stackingCanvas[idx];
+
+      if (!layer || !canvas) {
+        continue;
       }
 
-      const canvas = this._stackingCanvas[idx];
-      const ctx = canvas.getContext('2d') as CanvasRenderingContext2D;
-      const rc = new RoughCanvas(ctx.canvas);
+      const layerRenderBound = this._getLayerRenderBound(
+        layer.elements,
+        viewportBound
+      );
+      const resolvedLayerRenderBound = this._getResolvedStackingCanvasBound(
+        canvas,
+        layerRenderBound
+      );
 
-      ctx.clearRect(0, 0, canvas.width, canvas.height);
+      this._applyStackingCanvasLayout(canvas, resolvedLayerRenderBound);
+
+      if (
+        !resolvedLayerRenderBound ||
+        canvas.width === 0 ||
+        canvas.height === 0
+      ) {
+        continue;
+      }
+
+      const layerCtx = canvas.getContext('2d') as CanvasRenderingContext2D;
+      const layerRc = new RoughCanvas(layerCtx.canvas);
+
+      layerCtx.clearRect(0, 0, canvas.width, canvas.height);
+      layerCtx.save();
+      layerCtx.setTransform(matrix);
+
+      this._renderByBound(
+        layerCtx,
+        matrix,
+        layerRc,
+        resolvedLayerRenderBound,
+        layer.elements,
+        false,
+        renderStats
+      );
+    }
+
+    if (fullRender || this._mainCanvasDirty) {
+      allCanvasLayers.forEach((layer, idx) => {
+        if (!this._stackingCanvas[idx]) {
+          fallbackElement = fallbackElement.concat(layer.elements);
+        }
+      });
+
+      ctx.clearRect(0, 0, this.canvas.width, this.canvas.height);
       ctx.save();
       ctx.setTransform(matrix);
 
-      this._renderByBound(ctx, matrix, rc, viewportBounds, layer.elements);
-    });
+      this._renderByBound(
+        ctx,
+        matrix,
+        new RoughCanvas(ctx.canvas),
+        viewportBounds,
+        fallbackElement,
+        true,
+        renderStats
+      );
+    }
 
-    ctx.clearRect(0, 0, this.canvas.width, this.canvas.height);
-    ctx.save();
-
-    ctx.setTransform(matrix);
-
-    this._renderByBound(
-      ctx,
-      matrix,
-      new RoughCanvas(ctx.canvas),
-      viewportBounds,
-      fallbackElement,
-      true
+    const canvasMemorySnapshots = this._getCanvasMemorySnapshots();
+    const canvasMemoryBytes = canvasMemorySnapshots.reduce(
+      (sum, snapshot) => sum + snapshot.bytes,
+      0
     );
+    const layerTypes = this.layerManager.layers.map(layer => layer.type);
+    const renderDurationMs = performance.now() - renderStart;
+
+    this._debugMetrics.renderCount += 1;
+    this._debugMetrics.totalRenderDurationMs += renderDurationMs;
+    this._debugMetrics.lastRenderDurationMs = renderDurationMs;
+    this._debugMetrics.maxRenderDurationMs = Math.max(
+      this._debugMetrics.maxRenderDurationMs,
+      renderDurationMs
+    );
+    this._debugMetrics.lastRenderMetrics = renderStats;
+    this._debugMetrics.fallbackElementCount = fallbackElement.length;
+    this._debugMetrics.dirtyLayerRenderCount = stackingIndexesToRender.length;
+
+    this._lastDebugSnapshot = {
+      canvasMemorySnapshots,
+      canvasMemoryBytes,
+      canvasPixelCount: canvasMemorySnapshots.reduce(
+        (sum, snapshot) => sum + snapshot.width * snapshot.height,
+        0
+      ),
+      stackingCanvasCount: this._stackingCanvas.length,
+      canvasLayerCount: layerTypes.filter(type => type === 'canvas').length,
+      totalLayerCount: layerTypes.length,
+      pooledStackingCanvasCount: this._stackingCanvasPool.length,
+      visibleStackingCanvasCount: this._stackingCanvas.filter(
+        canvas => canvas.width > 0 && canvas.height > 0
+      ).length,
+    };
+
+    this._needsFullRender = false;
+    this._mainCanvasDirty = false;
+    this._dirtyStackingCanvasIndexes.clear();
   }
 
+  private _lastDebugSnapshot: Pick<
+    CanvasRendererDebugMetrics,
+    | 'canvasMemoryBytes'
+    | 'canvasMemorySnapshots'
+    | 'canvasPixelCount'
+    | 'canvasLayerCount'
+    | 'pooledStackingCanvasCount'
+    | 'stackingCanvasCount'
+    | 'totalLayerCount'
+    | 'visibleStackingCanvasCount'
+  > = {
+    canvasMemoryBytes: 0,
+    canvasMemorySnapshots: [],
+    canvasPixelCount: 0,
+    canvasLayerCount: 0,
+    pooledStackingCanvasCount: 0,
+    stackingCanvasCount: 0,
+    totalLayerCount: 0,
+    visibleStackingCanvasCount: 0,
+  };
+
   private _renderByBound(
     ctx: CanvasRenderingContext2D | null,
     matrix: DOMMatrix,
     rc: RoughCanvas,
     bound: IBound,
     surfaceElements?: SurfaceElementModel[],
-    overLay: boolean = false
+    overLay: boolean = false,
+    renderStats?: RenderPassStats
   ) {
     if (!ctx) return;
 
+    renderStats && (renderStats.renderByBoundCallCount += 1);
+
     const elements =
       surfaceElements ??
       (this.grid.search(bound, {
@@ -305,10 +741,12 @@ export class CanvasRenderer {
     for (const element of elements) {
       const display = (element.display ?? true) && !element.hidden;
       if (display && intersects(getBoundWithRotation(element), bound)) {
+        renderStats && (renderStats.visibleElementCount += 1);
         if (
           this.usePlaceholder &&
           !(element as GfxCompatibleInterface).forceFullRender
         ) {
+          renderStats && (renderStats.placeholderElementCount += 1);
           ctx.save();
           ctx.fillStyle = 'rgba(200, 200, 200, 0.5)';
           const drawX = element.x - bound.x;
@@ -316,6 +754,7 @@ export class CanvasRenderer {
           ctx.fillRect(drawX, drawY, element.w, element.h);
           ctx.restore();
         } else {
+          renderStats && (renderStats.renderedElementCount += 1);
           ctx.save();
           const renderFn = this.std.getOptional<ElementRenderer>(
             ElementRendererIdentifier(element.type)
@@ -333,6 +772,7 @@ export class CanvasRenderer {
     }
 
     if (overLay) {
+      renderStats && (renderStats.overlayCount += this._overlays.size);
       for (const overlay of this._overlays) {
         ctx.save();
         ctx.translate(-bound.x, -bound.y);
@@ -348,33 +788,38 @@ export class CanvasRenderer {
     const sizeUpdater = this._canvasSizeUpdater();
 
     sizeUpdater.update(this.canvas);
-
-    this._stackingCanvas.forEach(sizeUpdater.update);
-    this.refresh();
+    this._invalidate({ type: 'all' });
   }
 
   private _watchSurface(surfaceModel: SurfaceBlockModel) {
     this._disposables.add(
-      surfaceModel.elementAdded.subscribe(() => this.refresh())
+      surfaceModel.elementAdded.subscribe(() => this.refresh({ type: 'all' }))
     );
     this._disposables.add(
-      surfaceModel.elementRemoved.subscribe(() => this.refresh())
+      surfaceModel.elementRemoved.subscribe(() => this.refresh({ type: 'all' }))
     );
     this._disposables.add(
-      surfaceModel.localElementAdded.subscribe(() => this.refresh())
+      surfaceModel.localElementAdded.subscribe(() =>
+        this.refresh({ type: 'all' })
+      )
     );
     this._disposables.add(
-      surfaceModel.localElementDeleted.subscribe(() => this.refresh())
+      surfaceModel.localElementDeleted.subscribe(() =>
+        this.refresh({ type: 'all' })
+      )
     );
     this._disposables.add(
-      surfaceModel.localElementUpdated.subscribe(() => this.refresh())
+      surfaceModel.localElementUpdated.subscribe(({ model }) => {
+        this.refresh({ type: 'element', element: model });
+      })
     );
 
     this._disposables.add(
       surfaceModel.elementUpdated.subscribe(payload => {
         // ignore externalXYWH update cause it's updated by the renderer
         if (payload.props['externalXYWH']) return;
-        this.refresh();
+        const element = surfaceModel.getElementById(payload.id);
+        this.refresh(element ? { type: 'element', element } : { type: 'all' });
       })
     );
   }
@@ -382,7 +827,7 @@ export class CanvasRenderer {
   addOverlay(overlay: Overlay) {
     overlay.setRenderer(this);
     this._overlays.add(overlay);
-    this.refresh();
+    this.refresh({ type: 'main' });
   }
 
   /**
@@ -394,7 +839,7 @@ export class CanvasRenderer {
     container.append(this.canvas);
 
     this._resetSize();
-    this.refresh();
+    this.refresh({ type: 'all' });
   }
 
   dispose(): void {
@@ -453,8 +898,46 @@ export class CanvasRenderer {
     return this.provider.getPropertyValue?.(property) ?? '';
   }
 
-  refresh() {
-    if (this._refreshRafId !== null) return;
+  getDebugMetrics(): CanvasRendererDebugMetrics {
+    return {
+      ...this._debugMetrics,
+      ...this._lastDebugSnapshot,
+      canvasMemoryMegabytes:
+        this._lastDebugSnapshot.canvasMemoryBytes / 1024 / 1024,
+    };
+  }
+
+  resetDebugMetrics() {
+    this._debugMetrics = {
+      refreshCount: 0,
+      coalescedRefreshCount: 0,
+      renderCount: 0,
+      totalRenderDurationMs: 0,
+      lastRenderDurationMs: 0,
+      maxRenderDurationMs: 0,
+      lastRenderMetrics: this._createRenderPassStats(),
+      dirtyLayerRenderCount: 0,
+      fallbackElementCount: 0,
+    };
+    this._lastDebugSnapshot = {
+      canvasMemoryBytes: 0,
+      canvasMemorySnapshots: [],
+      canvasPixelCount: 0,
+      canvasLayerCount: 0,
+      pooledStackingCanvasCount: 0,
+      stackingCanvasCount: 0,
+      totalLayerCount: 0,
+      visibleStackingCanvasCount: 0,
+    };
+  }
+
+  refresh(target: RefreshTarget = { type: 'all' }) {
+    this._debugMetrics.refreshCount += 1;
+    this._invalidate(target);
+    if (this._refreshRafId !== null) {
+      this._debugMetrics.coalescedRefreshCount += 1;
+      return;
+    }
 
     this._refreshRafId = requestConnectedFrame(() => {
       this._refreshRafId = null;
@@ -469,6 +952,6 @@ export class CanvasRenderer {
 
     overlay.setRenderer(null);
     this._overlays.delete(overlay);
-    this.refresh();
+    this.refresh({ type: 'main' });
   }
 }

blocksuite/affine/blocks/surface/src/renderer/dom-renderer.ts

@@ -354,30 +354,37 @@ export class DomRenderer {
     this._disposables.add(
       surfaceModel.elementAdded.subscribe(payload => {
         this._markElementDirty(payload.id, UpdateType.ELEMENT_ADDED);
+        this._markViewportDirty();
         this.refresh();
       })
     );
     this._disposables.add(
       surfaceModel.elementRemoved.subscribe(payload => {
         this._markElementDirty(payload.id, UpdateType.ELEMENT_REMOVED);
+        this._markViewportDirty();
         this.refresh();
       })
     );
     this._disposables.add(
       surfaceModel.localElementAdded.subscribe(payload => {
         this._markElementDirty(payload.id, UpdateType.ELEMENT_ADDED);
+        this._markViewportDirty();
         this.refresh();
       })
     );
     this._disposables.add(
       surfaceModel.localElementDeleted.subscribe(payload => {
         this._markElementDirty(payload.id, UpdateType.ELEMENT_REMOVED);
+        this._markViewportDirty();
         this.refresh();
       })
     );
     this._disposables.add(
       surfaceModel.localElementUpdated.subscribe(payload => {
         this._markElementDirty(payload.model.id, UpdateType.ELEMENT_UPDATED);
+        if (payload.props['index'] || payload.props['groupId']) {
+          this._markViewportDirty();
+        }
         this.refresh();
       })
     );
@@ -387,6 +394,9 @@ export class DomRenderer {
         // ignore externalXYWH update cause it's updated by the renderer
         if (payload.props['externalXYWH']) return;
         this._markElementDirty(payload.id, UpdateType.ELEMENT_UPDATED);
+        if (payload.props['index'] || payload.props['childIds']) {
+          this._markViewportDirty();
+        }
         this.refresh();
       })
     );

blocksuite/affine/gfx/brush/src/renderer/dom/brush.ts

@@ -5,6 +5,8 @@ import {
 import type { BrushElementModel } from '@blocksuite/affine-model';
 import { DefaultTheme } from '@blocksuite/affine-model';
 
+import { renderBrushLikeDom } from './shared';
+
 export const BrushDomRendererExtension = DomElementRendererExtension(
   'brush',
   (
@@ -12,58 +14,11 @@ export const BrushDomRendererExtension = DomElementRendererExtension(
     domElement: HTMLElement,
     renderer: DomRenderer
   ) => {
-    const { zoom } = renderer.viewport;
-    const [, , w, h] = model.deserializedXYWH;
-
-    // Early return if invalid dimensions
-    if (w <= 0 || h <= 0) {
-      return;
-    }
-
-    // Early return if no commands
-    if (!model.commands) {
-      return;
-    }
-
-    // Clear previous content
-    domElement.innerHTML = '';
-
-    // Get color value
-    const color = renderer.getColorValue(model.color, DefaultTheme.black, true);
-
-    // Create SVG element
-    const svg = document.createElementNS('http://www.w3.org/2000/svg', 'svg');
-    svg.style.position = 'absolute';
-    svg.style.left = '0';
-    svg.style.top = '0';
-    svg.style.width = `${w * zoom}px`;
-    svg.style.height = `${h * zoom}px`;
-    svg.style.overflow = 'visible';
-    svg.style.pointerEvents = 'none';
-    svg.setAttribute('viewBox', `0 0 ${w} ${h}`);
-
-    // Apply rotation transform
-    if (model.rotate !== 0) {
-      svg.style.transform = `rotate(${model.rotate}deg)`;
-      svg.style.transformOrigin = 'center';
-    }
-
-    // Create path element for the brush stroke
-    const pathElement = document.createElementNS(
-      'http://www.w3.org/2000/svg',
-      'path'
-    );
-    pathElement.setAttribute('d', model.commands);
-    pathElement.setAttribute('fill', color);
-    pathElement.setAttribute('stroke', 'none');
-
-    svg.append(pathElement);
-    domElement.replaceChildren(svg);
-
-    // Set element size and position
-    domElement.style.width = `${w * zoom}px`;
-    domElement.style.height = `${h * zoom}px`;
-    domElement.style.overflow = 'visible';
-    domElement.style.pointerEvents = 'none';
+    renderBrushLikeDom({
+      model,
+      domElement,
+      renderer,
+      color: renderer.getColorValue(model.color, DefaultTheme.black, true),
+    });
   }
 );

blocksuite/affine/gfx/brush/src/renderer/dom/highlighter.ts

@@ -5,6 +5,8 @@ import {
 import type { HighlighterElementModel } from '@blocksuite/affine-model';
 import { DefaultTheme } from '@blocksuite/affine-model';
 
+import { renderBrushLikeDom } from './shared';
+
 export const HighlighterDomRendererExtension = DomElementRendererExtension(
   'highlighter',
   (
@@ -12,62 +14,15 @@ export const HighlighterDomRendererExtension = DomElementRendererExtension(
     domElement: HTMLElement,
     renderer: DomRenderer
   ) => {
-    const { zoom } = renderer.viewport;
-    const [, , w, h] = model.deserializedXYWH;
-
-    // Early return if invalid dimensions
-    if (w <= 0 || h <= 0) {
-      return;
-    }
-
-    // Early return if no commands
-    if (!model.commands) {
-      return;
-    }
-
-    // Clear previous content
-    domElement.innerHTML = '';
-
-    // Get color value
-    const color = renderer.getColorValue(
-      model.color,
-      DefaultTheme.hightlighterColor,
-      true
-    );
-
-    // Create SVG element
-    const svg = document.createElementNS('http://www.w3.org/2000/svg', 'svg');
-    svg.style.position = 'absolute';
-    svg.style.left = '0';
-    svg.style.top = '0';
-    svg.style.width = `${w * zoom}px`;
-    svg.style.height = `${h * zoom}px`;
-    svg.style.overflow = 'visible';
-    svg.style.pointerEvents = 'none';
-    svg.setAttribute('viewBox', `0 0 ${w} ${h}`);
-
-    // Apply rotation transform
-    if (model.rotate !== 0) {
-      svg.style.transform = `rotate(${model.rotate}deg)`;
-      svg.style.transformOrigin = 'center';
-    }
-
-    // Create path element for the highlighter stroke
-    const pathElement = document.createElementNS(
-      'http://www.w3.org/2000/svg',
-      'path'
-    );
-    pathElement.setAttribute('d', model.commands);
-    pathElement.setAttribute('fill', color);
-    pathElement.setAttribute('stroke', 'none');
-
-    svg.append(pathElement);
-    domElement.replaceChildren(svg);
-
-    // Set element size and position
-    domElement.style.width = `${w * zoom}px`;
-    domElement.style.height = `${h * zoom}px`;
-    domElement.style.overflow = 'visible';
-    domElement.style.pointerEvents = 'none';
+    renderBrushLikeDom({
+      model,
+      domElement,
+      renderer,
+      color: renderer.getColorValue(
+        model.color,
+        DefaultTheme.hightlighterColor,
+        true
+      ),
+    });
   }
 );

blocksuite/affine/gfx/brush/src/renderer/dom/shared.ts

@@ -0,0 +1,82 @@
+import type { DomRenderer } from '@blocksuite/affine-block-surface';
+import type {
+  BrushElementModel,
+  HighlighterElementModel,
+} from '@blocksuite/affine-model';
+
+const SVG_NS = 'http://www.w3.org/2000/svg';
+
+type BrushLikeModel = BrushElementModel | HighlighterElementModel;
+
+type RetainedBrushDom = {
+  path: SVGPathElement;
+  svg: SVGSVGElement;
+};
+
+const retainedBrushDom = new WeakMap<HTMLElement, RetainedBrushDom>();
+
+function clearBrushLikeDom(domElement: HTMLElement) {
+  retainedBrushDom.delete(domElement);
+  domElement.replaceChildren();
+}
+
+function getRetainedBrushDom(domElement: HTMLElement) {
+  const existing = retainedBrushDom.get(domElement);
+
+  if (existing) {
+    return existing;
+  }
+
+  const svg = document.createElementNS(SVG_NS, 'svg');
+  svg.style.position = 'absolute';
+  svg.style.left = '0';
+  svg.style.top = '0';
+  svg.style.overflow = 'visible';
+  svg.style.pointerEvents = 'none';
+
+  const path = document.createElementNS(SVG_NS, 'path');
+  path.setAttribute('stroke', 'none');
+  svg.append(path);
+
+  const retained = { svg, path };
+  retainedBrushDom.set(domElement, retained);
+  domElement.replaceChildren(svg);
+
+  return retained;
+}
+
+export function renderBrushLikeDom({
+  color,
+  domElement,
+  model,
+  renderer,
+}: {
+  color: string;
+  domElement: HTMLElement;
+  model: BrushLikeModel;
+  renderer: DomRenderer;
+}) {
+  const { zoom } = renderer.viewport;
+  const [, , w, h] = model.deserializedXYWH;
+
+  if (w <= 0 || h <= 0 || !model.commands) {
+    clearBrushLikeDom(domElement);
+    return;
+  }
+
+  const { path, svg } = getRetainedBrushDom(domElement);
+
+  svg.style.width = `${w * zoom}px`;
+  svg.style.height = `${h * zoom}px`;
+  svg.style.transform = model.rotate === 0 ? '' : `rotate(${model.rotate}deg)`;
+  svg.style.transformOrigin = model.rotate === 0 ? '' : 'center';
+  svg.setAttribute('viewBox', `0 0 ${w} ${h}`);
+
+  path.setAttribute('d', model.commands);
+  path.setAttribute('fill', color);
+
+  domElement.style.width = `${w * zoom}px`;
+  domElement.style.height = `${h * zoom}px`;
+  domElement.style.overflow = 'visible';
+  domElement.style.pointerEvents = 'none';
+}

blocksuite/affine/gfx/connector/src/renderer/dom-renderer.ts

@@ -14,6 +14,8 @@ import { PointLocation, SVGPathBuilder } from '@blocksuite/global/gfx';
 import { isConnectorWithLabel } from '../connector-manager';
 import { DEFAULT_ARROW_SIZE } from './utils';
 
+const SVG_NS = 'http://www.w3.org/2000/svg';
+
 interface PathBounds {
   minX: number;
   minY: number;
@@ -21,6 +23,15 @@ interface PathBounds {
   maxY: number;
 }
 
+type RetainedConnectorDom = {
+  defs: SVGDefsElement;
+  label: HTMLDivElement | null;
+  path: SVGPathElement;
+  svg: SVGSVGElement;
+};
+
+const retainedConnectorDom = new WeakMap<HTMLElement, RetainedConnectorDom>();
+
 function calculatePathBounds(path: PointLocation[]): PathBounds {
   if (path.length === 0) {
     return { minX: 0, minY: 0, maxX: 0, maxY: 0 };
@@ -81,10 +92,7 @@ function createArrowMarker(
   strokeWidth: number,
   isStart: boolean = false
 ): SVGMarkerElement {
-  const marker = document.createElementNS(
-    'http://www.w3.org/2000/svg',
-    'marker'
-  );
+  const marker = document.createElementNS(SVG_NS, 'marker');
   const size = DEFAULT_ARROW_SIZE * (strokeWidth / 2);
 
   marker.id = id;
@@ -98,10 +106,7 @@ function createArrowMarker(
 
   switch (style) {
     case 'Arrow': {
-      const path = document.createElementNS(
-        'http://www.w3.org/2000/svg',
-        'path'
-      );
+      const path = document.createElementNS(SVG_NS, 'path');
       path.setAttribute(
         'd',
         isStart ? 'M 20 5 L 10 10 L 20 15 Z' : 'M 0 5 L 10 10 L 0 15 Z'
@@ -112,10 +117,7 @@ function createArrowMarker(
       break;
     }
     case 'Triangle': {
-      const path = document.createElementNS(
-        'http://www.w3.org/2000/svg',
-        'path'
-      );
+      const path = document.createElementNS(SVG_NS, 'path');
       path.setAttribute(
         'd',
         isStart ? 'M 20 7 L 12 10 L 20 13 Z' : 'M 0 7 L 8 10 L 0 13 Z'
@@ -126,10 +128,7 @@ function createArrowMarker(
       break;
     }
     case 'Circle': {
-      const circle = document.createElementNS(
-        'http://www.w3.org/2000/svg',
-        'circle'
-      );
+      const circle = document.createElementNS(SVG_NS, 'circle');
       circle.setAttribute('cx', '10');
       circle.setAttribute('cy', '10');
       circle.setAttribute('r', '4');
@@ -139,10 +138,7 @@ function createArrowMarker(
       break;
     }
     case 'Diamond': {
-      const path = document.createElementNS(
-        'http://www.w3.org/2000/svg',
-        'path'
-      );
+      const path = document.createElementNS(SVG_NS, 'path');
       path.setAttribute('d', 'M 10 6 L 14 10 L 10 14 L 6 10 Z');
       path.setAttribute('fill', color);
       path.setAttribute('stroke', color);
@@ -154,13 +150,64 @@ function createArrowMarker(
   return marker;
 }
 
+function clearRetainedConnectorDom(element: HTMLElement) {
+  retainedConnectorDom.delete(element);
+  element.replaceChildren();
+}
+
+function getRetainedConnectorDom(element: HTMLElement): RetainedConnectorDom {
+  const existing = retainedConnectorDom.get(element);
+
+  if (existing) {
+    return existing;
+  }
+
+  const svg = document.createElementNS(SVG_NS, 'svg');
+  svg.style.position = 'absolute';
+  svg.style.overflow = 'visible';
+  svg.style.pointerEvents = 'none';
+
+  const defs = document.createElementNS(SVG_NS, 'defs');
+  const path = document.createElementNS(SVG_NS, 'path');
+  path.setAttribute('fill', 'none');
+  path.setAttribute('stroke-linecap', 'round');
+  path.setAttribute('stroke-linejoin', 'round');
+
+  svg.append(defs, path);
+  element.replaceChildren(svg);
+
+  const retained = {
+    svg,
+    defs,
+    path,
+    label: null,
+  };
+  retainedConnectorDom.set(element, retained);
+
+  return retained;
+}
+
+function getOrCreateLabelElement(retained: RetainedConnectorDom) {
+  if (retained.label) {
+    return retained.label;
+  }
+
+  const label = document.createElement('div');
+  retained.svg.insertAdjacentElement('afterend', label);
+  retained.label = label;
+
+  return label;
+}
+
 function renderConnectorLabel(
   model: ConnectorElementModel,
-  container: HTMLElement,
+  retained: RetainedConnectorDom,
   renderer: DomRenderer,
   zoom: number
 ) {
   if (!isConnectorWithLabel(model) || !model.labelXYWH) {
+    retained.label?.remove();
+    retained.label = null;
     return;
   }
 
@@ -176,8 +223,7 @@ function renderConnectorLabel(
     },
   } = model;
 
-  // Create label element
-  const labelElement = document.createElement('div');
+  const labelElement = getOrCreateLabelElement(retained);
   labelElement.style.position = 'absolute';
   labelElement.style.left = `${lx * zoom}px`;
   labelElement.style.top = `${ly * zoom}px`;
@@ -210,11 +256,7 @@ function renderConnectorLabel(
   labelElement.style.wordWrap = 'break-word';
 
   // Add text content
-  if (model.text) {
-    labelElement.textContent = model.text.toString();
-  }
-
-  container.append(labelElement);
+  labelElement.textContent = model.text ? model.text.toString() : '';
 }
 
 /**
@@ -241,14 +283,13 @@ export const connectorBaseDomRenderer = (
     stroke,
   } = model;
 
-  // Clear previous content
-  element.innerHTML = '';
-
-  // Early return if no path points
   if (!points || points.length < 2) {
+    clearRetainedConnectorDom(element);
     return;
   }
 
+  const retained = getRetainedConnectorDom(element);
+
   // Calculate bounds for the SVG viewBox
   const pathBounds = calculatePathBounds(points);
   const padding = Math.max(strokeWidth * 2, 20); // Add padding for arrows
@@ -257,8 +298,7 @@ export const connectorBaseDomRenderer = (
   const offsetX = pathBounds.minX - padding;
   const offsetY = pathBounds.minY - padding;
 
-  // Create SVG element
-  const svg = document.createElementNS('http://www.w3.org/2000/svg', 'svg');
+  const { defs, path, svg } = retained;
   svg.style.position = 'absolute';
   svg.style.left = `${offsetX * zoom}px`;
   svg.style.top = `${offsetY * zoom}px`;
@@ -268,49 +308,43 @@ export const connectorBaseDomRenderer = (
   svg.style.pointerEvents = 'none';
   svg.setAttribute('viewBox', `0 0 ${svgWidth / zoom} ${svgHeight / zoom}`);
 
-  // Create defs for markers
-  const defs = document.createElementNS('http://www.w3.org/2000/svg', 'defs');
-  svg.append(defs);
-
   const strokeColor = renderer.getColorValue(
     stroke,
     DefaultTheme.connectorColor,
     true
   );
 
-  // Create markers for endpoints
+  const markers: SVGMarkerElement[] = [];
   let startMarkerId = '';
   let endMarkerId = '';
 
   if (frontEndpointStyle !== 'None') {
     startMarkerId = `start-marker-${model.id}`;
-    const startMarker = createArrowMarker(
-      startMarkerId,
-      frontEndpointStyle,
-      strokeColor,
-      strokeWidth,
-      true
+    markers.push(
+      createArrowMarker(
+        startMarkerId,
+        frontEndpointStyle,
+        strokeColor,
+        strokeWidth,
+        true
+      )
     );
-    defs.append(startMarker);
   }
 
   if (rearEndpointStyle !== 'None') {
     endMarkerId = `end-marker-${model.id}`;
-    const endMarker = createArrowMarker(
-      endMarkerId,
-      rearEndpointStyle,
-      strokeColor,
-      strokeWidth,
-      false
+    markers.push(
+      createArrowMarker(
+        endMarkerId,
+        rearEndpointStyle,
+        strokeColor,
+        strokeWidth,
+        false
+      )
     );
-    defs.append(endMarker);
   }
 
-  // Create path element
-  const pathElement = document.createElementNS(
-    'http://www.w3.org/2000/svg',
-    'path'
-  );
+  defs.replaceChildren(...markers);
 
   // Adjust points relative to the SVG coordinate system
   const adjustedPoints = points.map(point => {
@@ -334,29 +368,25 @@ export const connectorBaseDomRenderer = (
   });
 
   const pathData = createConnectorPath(adjustedPoints, mode);
-  pathElement.setAttribute('d', pathData);
-  pathElement.setAttribute('stroke', strokeColor);
-  pathElement.setAttribute('stroke-width', String(strokeWidth));
-  pathElement.setAttribute('fill', 'none');
-  pathElement.setAttribute('stroke-linecap', 'round');
-  pathElement.setAttribute('stroke-linejoin', 'round');
-
-  // Apply stroke style
+  path.setAttribute('d', pathData);
+  path.setAttribute('stroke', strokeColor);
+  path.setAttribute('stroke-width', String(strokeWidth));
   if (strokeStyle === 'dash') {
-    pathElement.setAttribute('stroke-dasharray', '12,12');
+    path.setAttribute('stroke-dasharray', '12,12');
+  } else {
+    path.removeAttribute('stroke-dasharray');
   }
-
-  // Apply markers
   if (startMarkerId) {
-    pathElement.setAttribute('marker-start', `url(#${startMarkerId})`);
+    path.setAttribute('marker-start', `url(#${startMarkerId})`);
+  } else {
+    path.removeAttribute('marker-start');
   }
   if (endMarkerId) {
-    pathElement.setAttribute('marker-end', `url(#${endMarkerId})`);
+    path.setAttribute('marker-end', `url(#${endMarkerId})`);
+  } else {
+    path.removeAttribute('marker-end');
   }
 
-  svg.append(pathElement);
-  element.append(svg);
-
   // Set element size and position
   element.style.width = `${model.w * zoom}px`;
   element.style.height = `${model.h * zoom}px`;
@@ -370,7 +400,11 @@ export const connectorDomRenderer = (
   renderer: DomRenderer
 ): void => {
   connectorBaseDomRenderer(model, element, renderer);
-  renderConnectorLabel(model, element, renderer, renderer.viewport.zoom);
+
+  const retained = retainedConnectorDom.get(element);
+  if (!retained) return;
+
+  renderConnectorLabel(model, retained, renderer, renderer.viewport.zoom);
 };
 
 /**

blocksuite/affine/gfx/shape/src/element-renderer/shape-dom/index.ts

@@ -6,6 +6,37 @@ import { SVGShapeBuilder } from '@blocksuite/global/gfx';
 
 import { manageClassNames, setStyles } from './utils';
 
+const SVG_NS = 'http://www.w3.org/2000/svg';
+
+type RetainedShapeDom = {
+  polygon: SVGPolygonElement | null;
+  svg: SVGSVGElement | null;
+  text: HTMLDivElement | null;
+};
+
+type RetainedShapeSvg = {
+  polygon: SVGPolygonElement;
+  svg: SVGSVGElement;
+};
+
+const retainedShapeDom = new WeakMap<HTMLElement, RetainedShapeDom>();
+
+function getRetainedShapeDom(element: HTMLElement): RetainedShapeDom {
+  const existing = retainedShapeDom.get(element);
+
+  if (existing) {
+    return existing;
+  }
+
+  const retained = {
+    svg: null,
+    polygon: null,
+    text: null,
+  };
+  retainedShapeDom.set(element, retained);
+  return retained;
+}
+
 function applyShapeSpecificStyles(
   model: ShapeElementModel,
   element: HTMLElement,
@@ -14,10 +45,6 @@ function applyShapeSpecificStyles(
   // Reset properties that might be set by different shape types
   element.style.removeProperty('clip-path');
   element.style.removeProperty('border-radius');
-  // Clear DOM for shapes that don't use SVG, or if type changes from SVG-based to non-SVG-based
-  if (model.shapeType !== 'diamond' && model.shapeType !== 'triangle') {
-    while (element.firstChild) element.firstChild.remove();
-  }
 
   switch (model.shapeType) {
     case 'rect': {
@@ -42,6 +69,54 @@ function applyShapeSpecificStyles(
   // No 'else' needed to clear styles, as they are reset at the beginning of the function.
 }
 
+function getOrCreateSvg(
+  retained: RetainedShapeDom,
+  element: HTMLElement
+): RetainedShapeSvg {
+  if (retained.svg && retained.polygon) {
+    return {
+      svg: retained.svg,
+      polygon: retained.polygon,
+    };
+  }
+
+  const svg = document.createElementNS(SVG_NS, 'svg');
+  svg.setAttribute('width', '100%');
+  svg.setAttribute('height', '100%');
+  svg.setAttribute('preserveAspectRatio', 'none');
+
+  const polygon = document.createElementNS(SVG_NS, 'polygon');
+  svg.append(polygon);
+
+  retained.svg = svg;
+  retained.polygon = polygon;
+  element.prepend(svg);
+
+  return { svg, polygon };
+}
+
+function removeSvg(retained: RetainedShapeDom) {
+  retained.svg?.remove();
+  retained.svg = null;
+  retained.polygon = null;
+}
+
+function getOrCreateText(retained: RetainedShapeDom, element: HTMLElement) {
+  if (retained.text) {
+    return retained.text;
+  }
+
+  const text = document.createElement('div');
+  retained.text = text;
+  element.append(text);
+  return text;
+}
+
+function removeText(retained: RetainedShapeDom) {
+  retained.text?.remove();
+  retained.text = null;
+}
+
 function applyBorderStyles(
   model: ShapeElementModel,
   element: HTMLElement,
@@ -99,8 +174,7 @@ export const shapeDomRenderer = (
   const { zoom } = renderer.viewport;
   const unscaledWidth = model.w;
   const unscaledHeight = model.h;
-
-  const newChildren: Element[] = [];
+  const retained = getRetainedShapeDom(element);
 
   const fillColor = renderer.getColorValue(
     model.fillColor,
@@ -124,6 +198,7 @@ export const shapeDomRenderer = (
     // For diamond and triangle, fill and border are handled by inline SVG
     element.style.border = 'none'; // Ensure no standard CSS border interferes
     element.style.backgroundColor = 'transparent'; // Host element is transparent
+    const { polygon, svg } = getOrCreateSvg(retained, element);
 
     const strokeW = model.strokeWidth;
 
@@ -155,37 +230,30 @@ export const shapeDomRenderer = (
     // Determine fill color
     const finalFillColor = model.filled ? fillColor : 'transparent';
 
-    // Build SVG safely with DOM-API
-    const SVG_NS = 'http://www.w3.org/2000/svg';
-    const svg = document.createElementNS(SVG_NS, 'svg');
-    svg.setAttribute('width', '100%');
-    svg.setAttribute('height', '100%');
     svg.setAttribute('viewBox', `0 0 ${unscaledWidth} ${unscaledHeight}`);
-    svg.setAttribute('preserveAspectRatio', 'none');
-
-    const polygon = document.createElementNS(SVG_NS, 'polygon');
     polygon.setAttribute('points', svgPoints);
     polygon.setAttribute('fill', finalFillColor);
     polygon.setAttribute('stroke', finalStrokeColor);
     polygon.setAttribute('stroke-width', String(strokeW));
     if (finalStrokeDasharray !== 'none') {
       polygon.setAttribute('stroke-dasharray', finalStrokeDasharray);
+    } else {
+      polygon.removeAttribute('stroke-dasharray');
     }
-    svg.append(polygon);
-
-    newChildren.push(svg);
   } else {
     // Standard rendering for other shapes (e.g., rect, ellipse)
-    // innerHTML was already cleared by applyShapeSpecificStyles if necessary
+    removeSvg(retained);
     element.style.backgroundColor = model.filled ? fillColor : 'transparent';
     applyBorderStyles(model, element, strokeColor, zoom); // Uses standard CSS border
   }
 
   if (model.textDisplay && model.text) {
     const str = model.text.toString();
-    const textElement = document.createElement('div');
+    const textElement = getOrCreateText(retained, element);
     if (isRTL(str)) {
       textElement.dir = 'rtl';
+    } else {
+      textElement.removeAttribute('dir');
     }
     textElement.style.position = 'absolute';
     textElement.style.inset = '0';
@@ -210,12 +278,10 @@ export const shapeDomRenderer = (
       true
     );
     textElement.textContent = str;
-    newChildren.push(textElement);
+  } else {
+    removeText(retained);
   }
 
-  // Replace existing children to avoid memory leaks
-  element.replaceChildren(...newChildren);
-
   applyTransformStyles(model, element);
 
   manageClassNames(model, element);

blocksuite/affine/model/src/elements/connector/connector.ts

@@ -177,6 +177,11 @@ export class ConnectorElementModel extends GfxPrimitiveElementModel<ConnectorEle
   override getNearestPoint(point: IVec): IVec {
     const { mode, absolutePath: path } = this;
 
+    if (path.length === 0) {
+      const { x, y } = this;
+      return [x, y];
+    }
+
     if (mode === ConnectorMode.Straight) {
       const first = path[0];
       const last = path[path.length - 1];
@@ -213,6 +218,10 @@ export class ConnectorElementModel extends GfxPrimitiveElementModel<ConnectorEle
       h = bounds.h;
     }
 
+    if (path.length === 0) {
+      return 0.5;
+    }
+
     point[0] = Vec.clamp(point[0], x, x + w);
     point[1] = Vec.clamp(point[1], y, y + h);
 
@@ -258,6 +267,10 @@ export class ConnectorElementModel extends GfxPrimitiveElementModel<ConnectorEle
       h = bounds.h;
     }
 
+    if (path.length === 0) {
+      return [x + w / 2, y + h / 2];
+    }
+
     if (mode === ConnectorMode.Orthogonal) {
       const points = path.map<IVec>(p => [p[0], p[1]]);
       const point = Polyline.pointAt(points, offsetDistance);
@@ -300,6 +313,10 @@ export class ConnectorElementModel extends GfxPrimitiveElementModel<ConnectorEle
 
     const { mode, strokeWidth, absolutePath: path } = this;
 
+    if (path.length === 0) {
+      return false;
+    }
+
     const point =
       mode === ConnectorMode.Curve
         ? getBezierNearestPoint(getBezierParameters(path), currentPoint)

blocksuite/framework/global/src/__tests__/curve.unit.spec.ts

@@ -0,0 +1,22 @@
+import { describe, expect, test } from 'vitest';
+
+import { getBezierParameters } from '../gfx/curve.js';
+import { PointLocation } from '../gfx/model/index.js';
+
+describe('getBezierParameters', () => {
+  test('should handle empty path', () => {
+    expect(() => getBezierParameters([])).not.toThrow();
+    expect(getBezierParameters([])).toEqual([
+      new PointLocation(),
+      new PointLocation(),
+      new PointLocation(),
+      new PointLocation(),
+    ]);
+  });
+
+  test('should handle single-point path', () => {
+    const point = new PointLocation([10, 20]);
+
+    expect(getBezierParameters([point])).toEqual([point, point, point, point]);
+  });
+});

blocksuite/framework/global/src/gfx/curve.ts

@@ -142,6 +142,11 @@ export function getBezierNearestPoint(
 export function getBezierParameters(
   points: PointLocation[]
 ): BezierCurveParameters {
+  if (points.length === 0) {
+    const point = new PointLocation();
+    return [point, point, point, point];
+  }
+
   // Fallback for degenerate Bezier curve (all points are at the same position)
   if (points.length === 1) {
     const point = points[0];

blocksuite/framework/std/src/gfx/layer.ts

@@ -596,7 +596,7 @@ export class LayerManager extends GfxExtension {
   private _updateLayer(
     element: GfxModel | GfxLocalElementModel,
     props?: Record<string, unknown>,
-    oldValues?: Record<string, unknown>
+    _oldValues?: Record<string, unknown>
   ) {
     const modelType = this._getModelType(element);
     const isLocalElem = element instanceof GfxLocalElementModel;
@@ -613,16 +613,7 @@ export class LayerManager extends GfxExtension {
     };
 
     if (shouldUpdateGroupChildren) {
-      const group = element as GfxModel & GfxGroupCompatibleInterface;
-      const oldChildIds = childIdsChanged
-        ? Array.isArray(oldValues?.['childIds'])
-          ? (oldValues['childIds'] as string[])
-          : this._groupChildSnapshot.get(group.id)
-        : undefined;
-
-      const relatedElements = this._getRelatedGroupElements(group, oldChildIds);
-      this._refreshElementsInLayer(relatedElements);
-      this._syncGroupChildSnapshot(group);
+      this._reset();
       return true;
     }
 

blocksuite/framework/std/src/view/element/gfx-block-component.ts

@@ -31,6 +31,13 @@ function updateTransform(element: GfxBlockComponent) {
   element.style.transform = element.getCSSTransform();
 }
 
+function updateZIndex(element: GfxBlockComponent) {
+  const zIndex = element.toZIndex();
+  if (element.style.zIndex !== zIndex) {
+    element.style.zIndex = zIndex;
+  }
+}
+
 function updateBlockVisibility(view: GfxBlockComponent) {
   if (view.transformState$.value === 'active') {
     view.style.visibility = 'visible';
@@ -58,14 +65,22 @@ function handleGfxConnection(instance: GfxBlockComponent) {
     instance.store.slots.blockUpdated.subscribe(({ type, id }) => {
       if (id === instance.model.id && type === 'update') {
         updateTransform(instance);
+        updateZIndex(instance);
       }
     })
   );
 
+  instance.disposables.add(
+    instance.gfx.layer.slots.layerUpdated.subscribe(() => {
+      updateZIndex(instance);
+    })
+  );
+
   instance.disposables.add(
     effect(() => {
       updateBlockVisibility(instance);
       updateTransform(instance);
+      updateZIndex(instance);
     })
   );
 }

blocksuite/integration-test/src/__tests__/edgeless/layer.spec.ts

@@ -6,6 +6,7 @@ import type {
 import { ungroupCommand } from '@blocksuite/affine/gfx/group';
 import type {
   GroupElementModel,
+  MindmapElementModel,
   NoteBlockModel,
 } from '@blocksuite/affine/model';
 import { generateKeyBetween } from '@blocksuite/affine/std/gfx';
@@ -253,6 +254,40 @@ test('blocks should rerender when their z-index changed', async () => {
   assertBlocksContent();
 });
 
+test('block host z-index should update after reordering', async () => {
+  const backId = addNote(doc);
+  const frontId = addNote(doc);
+
+  await wait();
+
+  const getBlockHost = (id: string) =>
+    document.querySelector<HTMLElement>(
+      `affine-edgeless-root gfx-viewport > [data-block-id="${id}"]`
+    );
+
+  const backHost = getBlockHost(backId);
+  const frontHost = getBlockHost(frontId);
+
+  expect(backHost).not.toBeNull();
+  expect(frontHost).not.toBeNull();
+  expect(Number(backHost!.style.zIndex)).toBeLessThan(
+    Number(frontHost!.style.zIndex)
+  );
+
+  service.crud.updateElement(backId, {
+    index: service.layer.getReorderedIndex(
+      service.crud.getElementById(backId)!,
+      'front'
+    ),
+  });
+
+  await wait();
+
+  expect(Number(backHost!.style.zIndex)).toBeGreaterThan(
+    Number(frontHost!.style.zIndex)
+  );
+});
+
 describe('layer reorder functionality', () => {
   let ids: string[] = [];
 
@@ -428,14 +463,17 @@ describe('group related functionality', () => {
     const elements = [
       service.crud.addElement('shape', {
         shapeType: 'rect',
+        xywh: '[0,0,100,100]',
       })!,
       addNote(doc),
       service.crud.addElement('shape', {
         shapeType: 'rect',
+        xywh: '[120,0,100,100]',
       })!,
       addNote(doc),
       service.crud.addElement('shape', {
         shapeType: 'rect',
+        xywh: '[240,0,100,100]',
       })!,
     ];
 
@@ -528,6 +566,35 @@ describe('group related functionality', () => {
     expect(service.layer.layers[1].elements[0]).toBe(group);
   });
 
+  test("change mindmap index should update its nodes' layer", async () => {
+    const noteId = addNote(doc);
+    const mindmapId = service.crud.addElement('mindmap', {
+      children: {
+        text: 'root',
+        children: [{ text: 'child' }],
+      },
+    })!;
+
+    await wait();
+
+    const note = service.crud.getElementById(noteId)!;
+    const mindmap = service.crud.getElementById(
+      mindmapId
+    )! as MindmapElementModel;
+    const root = mindmap.tree.element;
+
+    expect(service.layer.getZIndex(root)).toBeGreaterThan(
+      service.layer.getZIndex(note)
+    );
+
+    mindmap.index = service.layer.getReorderedIndex(mindmap, 'back');
+    await wait();
+
+    expect(service.layer.getZIndex(root)).toBeLessThan(
+      service.layer.getZIndex(note)
+    );
+  });
+
   test('should keep relative index order of elements after group, ungroup, undo, redo', () => {
     const edgeless = getDocRootBlock(doc, editor, 'edgeless');
     const elementIds = [
@@ -769,6 +836,7 @@ test('indexed canvas should be inserted into edgeless portal when switch to edge
 
   service.crud.addElement('shape', {
     shapeType: 'rect',
+    xywh: '[0,0,100,100]',
   })!;
 
   addNote(doc);
@@ -777,6 +845,7 @@ test('indexed canvas should be inserted into edgeless portal when switch to edge
 
   service.crud.addElement('shape', {
     shapeType: 'rect',
+    xywh: '[120,0,100,100]',
   })!;
 
   editor.mode = 'page';
@@ -792,10 +861,10 @@ test('indexed canvas should be inserted into edgeless portal when switch to edge
     '.indexable-canvas'
   )[0] as HTMLCanvasElement;
 
-  expect(indexedCanvas.width).toBe(
+  expect(indexedCanvas.width).toBeLessThanOrEqual(
     (surface.renderer as CanvasRenderer).canvas.width
   );
-  expect(indexedCanvas.height).toBe(
+  expect(indexedCanvas.height).toBeLessThanOrEqual(
     (surface.renderer as CanvasRenderer).canvas.height
   );
   expect(indexedCanvas.width).not.toBe(0);