refactor: moving connector label to connector view (#11738)

### Changed
Moved connector label moving logic from `default-tool` to connector view.

#### Other infrastructure changes:​​
- Gfx element view now can handles drag events
- Added `context.preventDefault()` support to bypass built-in interactions in extension
- Handle the pointer events in element view will bypass the built-in interactions automatically

> The built-in interactions include element dragging, click selection, drag-to-scale operations, etc.

blocksuite/affine/blocks/root/src/edgeless/gfx-tool/default-tool-ext/ext.ts

@@ -1,14 +1,10 @@
 export enum DefaultModeDragType {
-  /** Moving connector label */
-  ConnectorLabelMoving = 'connector-label-moving',
   /** Moving selected contents */
   ContentMoving = 'content-moving',
   /** Native range dragging inside active note block */
   NativeEditing = 'native-editing',
   /** Default void state */
   None = 'none',
-  /** Dragging preview */
-  PreviewDragging = 'preview-dragging',
   /** Expanding the dragging area, select the content covered inside */
   Selecting = 'selecting',
 }

blocksuite/affine/blocks/root/src/edgeless/gfx-tool/default-tool.ts

@@ -2,12 +2,8 @@ import {
   type FrameOverlay,
   isFrameBlock,
 } from '@blocksuite/affine-block-frame';
+import { OverlayIdentifier } from '@blocksuite/affine-block-surface';
 import {
-  ConnectorUtils,
-  OverlayIdentifier,
-} from '@blocksuite/affine-block-surface';
-import {
-  type ConnectorElementModel,
   GroupElementModel,
   MindmapElementModel,
   NoteBlockModel,
@@ -16,7 +12,7 @@ import {
 import { resetNativeSelection } from '@blocksuite/affine-shared/utils';
 import { DisposableGroup } from '@blocksuite/global/disposable';
 import type { IVec } from '@blocksuite/global/gfx';
-import { Bound, Vec } from '@blocksuite/global/gfx';
+import { Bound } from '@blocksuite/global/gfx';
 import type { PointerEventState } from '@blocksuite/std';
 import {
   BaseTool,
@@ -29,7 +25,6 @@ import {
 import { effect } from '@preact/signals-core';
 
 import { calPanDelta } from '../utils/panning-utils.js';
-import { isCanvasElement } from '../utils/query.js';
 import { DefaultModeDragType } from './default-tool-ext/ext.js';
 
 export class DefaultTool extends BaseTool {
@@ -59,11 +54,6 @@ export class DefaultTool extends BaseTool {
     this.gfx.viewport.applyDeltaCenter(delta[0], delta[1]);
   };
 
-  // For moving the connector label
-  private _selectedConnector: ConnectorElementModel | null = null;
-
-  private _selectedConnectorLabelBounds: Bound | null = null;
-
   private _selectionRectTransition: null | {
     w: number;
     h: number;
@@ -168,6 +158,8 @@ export class DefaultTool extends BaseTool {
 
   enableHover = true;
 
+  dragging = false;
+
   /**
    * Get the end position of the dragging area in the model coordinate
    */
@@ -232,20 +224,6 @@ export class DefaultTool extends BaseTool {
             editing: false,
           });
         }
-
-        if (
-          isCanvasElement(selected) &&
-          ConnectorUtils.isConnectorWithLabel(selected) &&
-          (selected as ConnectorElementModel).labelIncludesPoint(
-            this.gfx.viewport.toModelCoord(x, y)
-          )
-        ) {
-          this._selectedConnector = selected as ConnectorElementModel;
-          this._selectedConnectorLabelBounds = Bound.fromXYWH(
-            this._selectedConnector.labelXYWH!
-          );
-          return DefaultModeDragType.ConnectorLabelMoving;
-        }
       }
 
       return this.edgelessSelectionManager.editing
@@ -259,20 +237,6 @@ export class DefaultTool extends BaseTool {
           editing: false,
         });
 
-        if (
-          isCanvasElement(selected) &&
-          ConnectorUtils.isConnectorWithLabel(selected) &&
-          (selected as ConnectorElementModel).labelIncludesPoint(
-            this.gfx.viewport.toModelCoord(x, y)
-          )
-        ) {
-          this._selectedConnector = selected as ConnectorElementModel;
-          this._selectedConnectorLabelBounds = Bound.fromXYWH(
-            this._selectedConnector.labelXYWH!
-          );
-          return DefaultModeDragType.ConnectorLabelMoving;
-        }
-
         return DefaultModeDragType.ContentMoving;
       } else {
         return DefaultModeDragType.Selecting;
@@ -280,24 +244,6 @@ export class DefaultTool extends BaseTool {
     }
   }
 
-  private _moveLabel(delta: IVec) {
-    const connector = this._selectedConnector;
-    let bounds = this._selectedConnectorLabelBounds;
-    if (!connector || !bounds) return;
-    bounds = bounds.clone();
-    const center = connector.getNearestPoint(
-      Vec.add(bounds.center, delta) as IVec
-    );
-    const distance = connector.getOffsetDistanceByPoint(center as IVec);
-    bounds.center = center;
-    this.gfx.updateElement(connector, {
-      labelXYWH: bounds.toXYWH(),
-      labelOffset: {
-        distance,
-      },
-    });
-  }
-
   private _pick(x: number, y: number, options?: PointTestOptions) {
     const modelPos = this.gfx.viewport.toModelCoord(x, y);
 
@@ -387,7 +333,7 @@ export class DefaultTool extends BaseTool {
       resetNativeSelection(null);
     }
 
-    this.interactivity?.dispatch('click', e);
+    this.interactivity?.dispatchEvent('click', e);
   }
 
   override deactivate() {
@@ -409,21 +355,28 @@ export class DefaultTool extends BaseTool {
       return;
     }
 
-    this.interactivity?.dispatch('dblclick', e);
+    this.interactivity?.dispatchEvent('dblclick', e);
   }
 
-  override dragEnd() {
-    if (this.edgelessSelectionManager.editing) return;
+  override dragEnd(e: PointerEventState) {
+    this.interactivity?.dispatchEvent('dragend', e);
 
+    if (this.edgelessSelectionManager.editing || !this.dragging) return;
+
+    this.dragging = false;
     this.frameOverlay.clear();
     this._toBeMoved = [];
-    this._selectedConnector = null;
-    this._selectedConnectorLabelBounds = null;
     this._clearSelectingState();
     this.dragType = DefaultModeDragType.None;
   }
 
   override dragMove(e: PointerEventState) {
+    this.interactivity?.dispatchEvent('dragmove', e);
+
+    if (!this.dragging) {
+      return;
+    }
+
     const { viewport } = this.gfx;
     switch (this.dragType) {
       case DefaultModeDragType.Selecting: {
@@ -441,12 +394,6 @@ export class DefaultTool extends BaseTool {
       case DefaultModeDragType.ContentMoving: {
         break;
       }
-      case DefaultModeDragType.ConnectorLabelMoving: {
-        const dx = this.dragLastPos[0] - this.dragStartPos[0];
-        const dy = this.dragLastPos[1] - this.dragStartPos[1];
-        this._moveLabel([dx, dy]);
-        break;
-      }
       case DefaultModeDragType.NativeEditing: {
         // TODO reset if drag out of note
         break;
@@ -456,7 +403,18 @@ export class DefaultTool extends BaseTool {
 
   // eslint-disable-next-line @typescript-eslint/no-misused-promises
   override async dragStart(e: PointerEventState) {
-    if (this.edgelessSelectionManager.editing) return;
+    const { preventDefaultState, handledByView } =
+      this.interactivity?.dispatchEvent('dragstart', e) ?? {};
+
+    if (
+      this.edgelessSelectionManager.editing ||
+      preventDefaultState ||
+      handledByView
+    )
+      return;
+
+    this.dragging = true;
+
     // Determine the drag type based on the current state and event
     let dragType = this._determineDragType(e);
 
@@ -508,7 +466,7 @@ export class DefaultTool extends BaseTool {
   }
 
   override pointerDown(e: PointerEventState): void {
-    this.interactivity?.dispatch('pointerdown', e);
+    this.interactivity?.dispatchEvent('pointerdown', e);
   }
 
   override pointerMove(e: PointerEventState) {
@@ -527,11 +485,11 @@ export class DefaultTool extends BaseTool {
       this.frameOverlay.clear();
     }
 
-    this.interactivity?.dispatch('pointermove', e);
+    this.interactivity?.dispatchEvent('pointermove', e);
   }
 
   override pointerUp(e: PointerEventState) {
-    this.interactivity?.dispatch('pointerup', e);
+    this.interactivity?.dispatchEvent('pointerup', e);
   }
 
   override tripleClick() {}

blocksuite/affine/blocks/root/src/edgeless/interact-extensions/dblclick-add-edgeless-text.ts

@@ -6,14 +6,17 @@ import {
   FeatureFlagService,
   TelemetryProvider,
 } from '@blocksuite/affine-shared/services';
-import type { PointerEventState } from '@blocksuite/std';
-import { InteractivityExtension } from '@blocksuite/std/gfx';
+import {
+  type GfxInteractivityContext,
+  InteractivityExtension,
+} from '@blocksuite/std/gfx';
 
 export class DblClickAddEdgelessText extends InteractivityExtension {
   static override key = 'dbl-click-add-edgeless-text';
 
   override mounted() {
-    this.event.on('dblclick', (e: PointerEventState) => {
+    this.event.on('dblclick', (ctx: GfxInteractivityContext) => {
+      const { event: e } = ctx;
       const textFlag = this.std.store
         .get(FeatureFlagService)
         .getFlag('enable_edgeless_text');

blocksuite/affine/gfx/connector/src/view/view.ts

@@ -1,8 +1,14 @@
-import type { ConnectorElementModel } from '@blocksuite/affine-model';
+import {
+  type ConnectorElementModel,
+  LocalShapeElementModel,
+} from '@blocksuite/affine-model';
+import { Bound, serializeXYWH, Vec } from '@blocksuite/global/gfx';
+import type { PointerEventState } from '@blocksuite/std';
 import {
   type DragEndContext,
   type DragMoveContext,
   type DragStartContext,
+  generateKeyBetween,
   GfxElementModelView,
 } from '@blocksuite/std/gfx';
 
@@ -30,11 +36,17 @@ export class ConnectorElementView extends GfxElementModelView<ConnectorElementMo
   override onCreated(): void {
     super.onCreated();
 
-    this._initDblClickToEdit();
+    this._initLabelMoving();
   }
 
-  private _initDblClickToEdit(): void {
-    this.on('dblclick', evt => {
+  private _initLabelMoving(): void {
+    let curLabelElement: LocalShapeElementModel | null = null;
+
+    if (this.model.isLocked()) {
+      return;
+    }
+
+    const enterLabelEditor = (evt: PointerEventState) => {
       const edgeless = this.std.view.getBlock(this.std.store.root!.id);
 
       if (edgeless && !this.model.isLocked()) {
@@ -44,6 +56,121 @@ export class ConnectorElementView extends GfxElementModelView<ConnectorElementMo
           this.gfx.viewport.toModelCoord(evt.x, evt.y)
         );
       }
+    };
+    const getCurrentPosition = (evt: PointerEventState) => {
+      const [x, y] = this.gfx.viewport.toModelCoord(evt.x, evt.y);
+      return {
+        x,
+        y,
+        clientX: evt.raw.clientX,
+        clientY: evt.raw.clientY,
+      };
+    };
+    const watchEvent = (labelModel: LocalShapeElementModel) => {
+      const view = this.gfx.view.get(labelModel) as GfxElementModelView;
+      const connectorModel = this.model;
+
+      let labelBound: Bound | null = null;
+      let startPoint = {
+        x: 0,
+        y: 0,
+        clientX: 0,
+        clientY: 0,
+      };
+      let lastPoint = {
+        x: 0,
+        y: 0,
+        clientX: 0,
+        clientY: 0,
+      };
+
+      view.on('dblclick', evt => {
+        enterLabelEditor(evt);
+      });
+      view.on('dragstart', evt => {
+        startPoint = getCurrentPosition(evt);
+        labelBound = Bound.deserialize(labelModel.xywh);
+
+        connectorModel.stash('labelXYWH');
+        connectorModel.stash('labelOffset');
+      });
+
+      view.on('dragmove', evt => {
+        if (!labelBound) {
+          return;
+        }
+
+        lastPoint = getCurrentPosition(evt);
+        const newBound = labelBound.clone();
+        const delta = [lastPoint.x - startPoint.x, lastPoint.y - startPoint.y];
+        const center = connectorModel.getNearestPoint(
+          Vec.add(newBound.center, delta)
+        );
+        const distance = connectorModel.getOffsetDistanceByPoint(center);
+        newBound.center = center;
+
+        connectorModel.labelXYWH = newBound.toXYWH();
+        connectorModel.labelOffset = {
+          distance,
+        };
+      });
+
+      view.on('dragend', () => {
+        if (labelBound) {
+          labelBound = null;
+          connectorModel.pop('labelXYWH');
+          connectorModel.pop('labelOffset');
+        }
+      });
+    };
+    const updateLabelElement = () => {
+      if (!this.model.labelXYWH || !this.model.text) {
+        // Clean up existing label element if conditions are no longer met
+        if (curLabelElement) {
+          this.surface.deleteLocalElement(curLabelElement);
+          curLabelElement = null;
+        }
+        return;
+      }
+
+      const labelElement =
+        curLabelElement || new LocalShapeElementModel(this.surface);
+      labelElement.xywh = serializeXYWH(...this.model.labelXYWH);
+      labelElement.index = generateKeyBetween(this.model.index, null);
+
+      if (!curLabelElement) {
+        curLabelElement = labelElement;
+
+        labelElement.fillColor = 'transparent';
+        labelElement.strokeColor = 'transparent';
+        labelElement.strokeWidth = 0;
+
+        this.surface.addLocalElement(labelElement);
+        this.disposable.add(() => {
+          this.surface.deleteLocalElement(labelElement);
+        });
+        watchEvent(labelElement);
+      }
+    };
+
+    this.disposable.add(
+      this.model.propsUpdated.subscribe(payload => {
+        if (
+          payload.key === 'labelXYWH' ||
+          payload.key === 'text' ||
+          payload.key === 'index'
+        ) {
+          updateLabelElement();
+        }
+      })
+    );
+
+    updateLabelElement();
+
+    this.on('dblclick', evt => {
+      if (!curLabelElement) {
+        enterLabelEditor(evt);
+      }
     });
   }
 }

blocksuite/affine/gfx/shape/src/view.ts

@@ -1,4 +1,4 @@
-import type { ShapeElementModel } from '@blocksuite/affine-model';
+import { ShapeElementModel } from '@blocksuite/affine-model';
 import { GfxElementModelView } from '@blocksuite/std/gfx';
 
 import { mountShapeTextEditor } from './text/edgeless-shape-text-editor';
@@ -16,7 +16,11 @@ export class ShapeElementView extends GfxElementModelView<ShapeElementModel> {
     this.on('dblclick', () => {
       const edgeless = this.std.view.getBlock(this.std.store.root!.id);
 
-      if (edgeless && !this.model.isLocked()) {
+      if (
+        edgeless &&
+        !this.model.isLocked() &&
+        this.model instanceof ShapeElementModel
+      ) {
         mountShapeTextEditor(this.model, edgeless);
       }
     });

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

@@ -24,6 +24,7 @@ export type {
   ExtensionDragEndContext,
   ExtensionDragMoveContext,
   ExtensionDragStartContext,
+  GfxInteractivityContext,
   SelectedContext,
 } from './interactivity/index.js';
 export {

blocksuite/framework/std/src/gfx/interactivity/event.ts

@@ -1,3 +1,5 @@
+import type { PointerEventState, UIEventState } from '../../event';
+
 export type SupportedEvents =
   | 'click'
   | 'dblclick'
@@ -5,4 +7,42 @@ export type SupportedEvents =
   | 'pointerenter'
   | 'pointerleave'
   | 'pointermove'
-  | 'pointerup';
+  | 'pointerup'
+  | 'dragstart'
+  | 'dragmove'
+  | 'dragend';
+
+export type GfxInteractivityContext<
+  EventState extends UIEventState = PointerEventState,
+  RawEvent extends Event = EventState['event'],
+> = {
+  event: EventState;
+
+  /**
+   * The raw dom event.
+   */
+  raw: RawEvent;
+
+  /**
+   * Prevent the default gfx interaction
+   */
+  preventDefault: () => void;
+};
+
+export const createInteractionContext = (event: PointerEventState) => {
+  let preventDefaultState = false;
+
+  return {
+    context: {
+      event,
+      raw: event.raw,
+      preventDefault: () => {
+        preventDefaultState = true;
+        event.raw.preventDefault();
+      },
+    },
+    get preventDefaultState() {
+      return preventDefaultState;
+    },
+  };
+};

blocksuite/framework/std/src/gfx/interactivity/extension/base.ts

@@ -2,11 +2,10 @@ import { type Container, createIdentifier } from '@blocksuite/global/di';
 import { BlockSuiteError, ErrorCode } from '@blocksuite/global/exceptions';
 import { Extension } from '@blocksuite/store';
 
-import type { PointerEventState } from '../../../event/index.js';
 import type { GfxController } from '../../controller.js';
 import { GfxControllerIdentifier } from '../../identifiers.js';
 import type { GfxModel } from '../../model/model.js';
-import type { SupportedEvents } from '../event.js';
+import type { GfxInteractivityContext, SupportedEvents } from '../event.js';
 import type { ExtensionElementsCloneContext } from '../types/clone.js';
 import type {
   DragExtensionInitializeContext,
@@ -64,10 +63,13 @@ export class InteractivityExtension extends Extension {
 export class InteractivityEventAPI {
   private readonly _handlersMap = new Map<
     SupportedEvents,
-    ((evt: PointerEventState) => void)[]
+    ((evt: GfxInteractivityContext) => void)[]
   >();
 
-  on(eventName: SupportedEvents, handler: (evt: PointerEventState) => void) {
+  on(
+    eventName: SupportedEvents,
+    handler: (evt: GfxInteractivityContext) => void
+  ) {
     const handlers = this._handlersMap.get(eventName) ?? [];
     handlers.push(handler);
     this._handlersMap.set(eventName, handlers);
@@ -81,7 +83,7 @@ export class InteractivityEventAPI {
     };
   }
 
-  emit(eventName: SupportedEvents, evt: PointerEventState) {
+  emit(eventName: SupportedEvents, evt: GfxInteractivityContext) {
     const handlers = this._handlersMap.get(eventName);
     if (!handlers) {
       return;

blocksuite/framework/std/src/gfx/interactivity/gfx-view-event-handler.ts

@@ -3,14 +3,15 @@ import last from 'lodash-es/last';
 
 import type { PointerEventState } from '../../event';
 import type { GfxController } from '../controller.js';
-import type { GfxElementModelView } from '../view/view.js';
+import type { GfxElementModelView, SupportedEvent } from '../view/view.js';
 
 export class GfxViewEventManager {
-  private _currentStackedElm: GfxElementModelView[] = [];
+  private _hoveredElementsStack: GfxElementModelView[] = [];
+  private _draggingElement: GfxElementModelView | null = null;
 
   private _callInReverseOrder(
     callback: (view: GfxElementModelView) => void,
-    arr = this._currentStackedElm
+    arr = this._hoveredElementsStack
   ) {
     for (let i = arr.length - 1; i >= 0; i--) {
       const view = arr[i];
@@ -21,26 +22,52 @@ export class GfxViewEventManager {
 
   constructor(private readonly gfx: GfxController) {}
 
-  click(_evt: PointerEventState): void {
-    last(this._currentStackedElm)?.dispatch('click', _evt);
+  dispatch(eventName: SupportedEvent, evt: PointerEventState) {
+    if (eventName === 'pointermove') {
+      this._handlePointerMove(evt);
+      return false;
+    } else if (eventName.startsWith('drag')) {
+      return this._handleDrag(
+        eventName as 'dragstart' | 'dragend' | 'dragmove',
+        evt
+      );
+    } else {
+      return last(this._hoveredElementsStack)?.dispatch(eventName, evt);
+    }
   }
 
-  dblClick(_evt: PointerEventState): void {
-    last(this._currentStackedElm)?.dispatch('dblclick', _evt);
+  private _handleDrag(
+    evtName: 'dragstart' | 'dragend' | 'dragmove',
+    _evt: PointerEventState
+  ): boolean {
+    switch (evtName) {
+      case 'dragstart': {
+        if (this._draggingElement) {
+          this._draggingElement.dispatch('dragend', _evt);
+        }
+        this._draggingElement = last(this._hoveredElementsStack) ?? null;
+        return this._draggingElement?.dispatch('dragstart', _evt) ?? false;
+      }
+      case 'dragmove': {
+        return this._draggingElement?.dispatch('dragmove', _evt) ?? false;
+      }
+      case 'dragend': {
+        const dispatched =
+          this._draggingElement?.dispatch('dragend', _evt) ?? false;
+        this._draggingElement = null;
+        return dispatched;
+      }
+    }
   }
 
-  pointerDown(_evt: PointerEventState): void {
-    last(this._currentStackedElm)?.dispatch('pointerdown', _evt);
-  }
-
-  pointerMove(_evt: PointerEventState): void {
+  private _handlePointerMove(_evt: PointerEventState): void {
     const [x, y] = this.gfx.viewport.toModelCoord(_evt.x, _evt.y);
     const hoveredElmViews = this.gfx.grid
       .search(new Bound(x - 5, y - 5, 10, 10), {
         filter: ['canvas', 'local'],
       })
       .map(model => this.gfx.view.get(model)) as GfxElementModelView[];
-    const currentStackedViews = new Set(this._currentStackedElm);
+    const currentStackedViews = new Set(this._hoveredElementsStack);
     const visited = new Set<GfxElementModelView>();
 
     this._callInReverseOrder(view => {
@@ -54,10 +81,6 @@ export class GfxViewEventManager {
     this._callInReverseOrder(
       view => !visited.has(view) && view.dispatch('pointerleave', _evt)
     );
-    this._currentStackedElm = hoveredElmViews;
-  }
-
-  pointerUp(_evt: PointerEventState): void {
-    last(this._currentStackedElm)?.dispatch('pointerup', _evt);
+    this._hoveredElementsStack = hoveredElmViews;
   }
 }

blocksuite/framework/std/src/gfx/interactivity/index.ts

@@ -1,3 +1,4 @@
+export type { GfxInteractivityContext } from './event.js';
 export { InteractivityExtension } from './extension/base.js';
 export { GfxViewEventManager } from './gfx-view-event-handler.js';
 export { InteractivityIdentifier, InteractivityManager } from './manager.js';

blocksuite/framework/std/src/gfx/interactivity/manager.ts

@@ -5,7 +5,7 @@ import { Bound, Point } from '@blocksuite/global/gfx';
 import type { PointerEventState } from '../../event/state/pointer.js';
 import { GfxExtension, GfxExtensionIdentifier } from '../extension.js';
 import type { GfxModel } from '../model/model.js';
-import type { SupportedEvents } from './event.js';
+import { createInteractionContext, type SupportedEvents } from './event.js';
 import {
   type InteractivityActionAPI,
   type InteractivityEventAPI,
@@ -30,16 +30,6 @@ export const InteractivityIdentifier = GfxExtensionIdentifier(
   'interactivity-manager'
 ) as ServiceIdentifier<InteractivityManager>;
 
-const CAMEL_CASE_MAP: {
-  [key in ExtensionPointerHandler]: keyof GfxViewEventManager;
-} = {
-  click: 'click',
-  dblclick: 'dblClick',
-  pointerdown: 'pointerDown',
-  pointermove: 'pointerMove',
-  pointerup: 'pointerUp',
-};
-
 export class InteractivityManager extends GfxExtension {
   static override key = 'interactivity-manager';
 
@@ -78,20 +68,26 @@ export class InteractivityManager extends GfxExtension {
   }
 
   /**
-   * Dispatch the event to canvas elements
+   * Dispatch event to extensions and gfx view.
    * @param eventName
    * @param evt
+   * @returns
    */
-  dispatch(eventName: ExtensionPointerHandler, evt: PointerEventState) {
-    const handlerName = CAMEL_CASE_MAP[eventName];
-
-    this.canvasEventHandler[handlerName](evt);
-
+  dispatchEvent(eventName: ExtensionPointerHandler, evt: PointerEventState) {
+    const { context, preventDefaultState } = createInteractionContext(evt);
     const extensions = this.interactExtensions;
 
     extensions.forEach(ext => {
-      (ext.event as InteractivityEventAPI).emit(eventName, evt);
+      (ext.event as InteractivityEventAPI).emit(eventName, context);
     });
+
+    const handledByView =
+      this.canvasEventHandler.dispatch(eventName, evt) ?? false;
+
+    return {
+      preventDefaultState,
+      handledByView,
+    };
   }
 
   dispatchOnSelected(evt: PointerEventState) {
@@ -126,6 +122,14 @@ export class InteractivityManager extends GfxExtension {
     return false;
   }
 
+  /**
+   * Initialize drag operation for elements.
+   * Handles drag start, move and end events automatically.
+   * Note: Call this when mouse is already down.
+   *
+   * @param options
+   * @returns
+   */
   initializeDrag(options: DragInitializationOption) {
     let cancelledByExt = false;
 

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

@@ -26,6 +26,9 @@ export type EventsHandlerMap = {
   pointerleave: PointerEventState;
   pointermove: PointerEventState;
   pointerup: PointerEventState;
+  dragstart: PointerEventState;
+  dragmove: PointerEventState;
+  dragend: PointerEventState;
 };
 
 export type SupportedEvent = keyof EventsHandlerMap;
@@ -97,11 +100,24 @@ export class GfxElementModelView<
     return this.model.containsBound(bounds);
   }
 
+  /**
+   * Dispatches an event to the view.
+   * @param event
+   * @param evt
+   * @returns Whether the event view has any handlers for the event.
+   */
   dispatch<K extends keyof EventsHandlerMap>(
     event: K,
     evt: EventsHandlerMap[K]
   ) {
-    this._handlers.get(event)?.forEach(callback => callback(evt));
+    const handlers = this._handlers.get(event);
+
+    if (handlers?.length) {
+      handlers.forEach(callback => callback(evt));
+      return true;
+    }
+
+    return false;
   }
 
   getLineIntersections(start: IVec, end: IVec) {