GLSP-1399: Fix MousePositionTracker (eclipse-glsp#391)

Ensure that the `GLSPMousePositionTracker` correctly calculates the
diagram local mouse position

CHANGELOG.md

@@ -4,6 +4,8 @@
 
 ### Changes
 
+-   [diagram] Ensure that `GLSPMousePositionTracker` correctly calculates the current position in diagram local coordinates [#391](https://github.com/eclipse-glsp/glsp-client/pull/391)
+
 ### Potentially breaking changes
 
 ## [v2.2.1 - 22/07/2024](https://github.com/eclipse-glsp/glsp-client/releases/tag/v2.2.1)

packages/client/src/base/mouse-position-tracker.ts

@@ -14,33 +14,21 @@
  *
  * SPDX-License-Identifier: EPL-2.0 OR GPL-2.0 WITH Classpath-exception-2.0
  ********************************************************************************/
-import {
-    Action,
-    DOMHelper,
-    GModelElement,
-    MousePositionTracker,
-    Point,
-    TYPES,
-    ViewerOptions,
-    getAbsoluteClientBounds
-} from '@eclipse-glsp/sprotty';
-import { inject, injectable } from 'inversify';
+import { Action, GModelElement, MousePositionTracker, Point } from '@eclipse-glsp/sprotty';
+import { injectable } from 'inversify';
 import { Ranked } from './ranked';
 
 @injectable()
 export class GLSPMousePositionTracker extends MousePositionTracker implements Ranked {
     /* we want to be executed before all default mouse listeners since we are just tracking the position and others may need it */
     rank = Ranked.DEFAULT_RANK - 200;
 
-    @inject(TYPES.ViewerOptions) protected viewerOptions: ViewerOptions;
-    @inject(TYPES.DOMHelper) protected domHelper: DOMHelper;
-
     override mouseMove(target: GModelElement, event: MouseEvent): (Action | Promise<Action>)[] {
         // we cannot simply use the offsetX and offsetY properties of the event since they also consider nested HTML elements
         // such as foreignObjects or the projection bars divs. Instead, we manually translate the client coordinates to the diagram
-        const clientToRoot = getAbsoluteClientBounds(target.root, this.domHelper, this.viewerOptions);
+        const globalOrigin = target.root.canvasBounds;
         const clientToPosition = { x: event.clientX, y: event.clientY };
-        const rootToPosition = Point.subtract(clientToPosition, clientToRoot);
+        const rootToPosition = Point.subtract(clientToPosition, globalOrigin);
         const positionOnDiagram = target.root.parentToLocal(rootToPosition);
         this.lastPosition = positionOnDiagram;
         return [];