Initial

resources/app/client/core/mouse.js

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+/**
+ * Management class for Mouse events
+ */
+class MouseManager {
+  constructor() {
+    this._wheelTime = 0;
+  }
+
+  /**
+   * Specify a rate limit for mouse wheel to gate repeated scrolling.
+   * This is especially important for continuous scrolling mice which emit hundreds of events per second.
+   * This designates a minimum number of milliseconds which must pass before another wheel event is handled
+   * @type {number}
+   */
+  static MOUSE_WHEEL_RATE_LIMIT = 50;
+
+  /* -------------------------------------------- */
+
+  /**
+   * Begin listening to mouse events.
+   * @internal
+   */
+  _activateListeners() {
+    window.addEventListener("wheel", this._onWheel.bind(this), {passive: false});
+  }
+
+  /* -------------------------------------------- */
+
+  /**
+   * Master mouse-wheel event handler
+   * @param {WheelEvent} event    The mouse wheel event
+   * @private
+   */
+  _onWheel(event) {
+
+    // Prevent zooming the entire browser window
+    if ( event.ctrlKey ) event.preventDefault();
+
+    // Interpret shift+scroll as vertical scroll
+    let dy = event.delta = event.deltaY;
+    if ( event.shiftKey && (dy === 0) ) {
+      dy = event.delta = event.deltaX;
+    }
+    if ( dy === 0 ) return;
+
+    // Take no actions if the canvas is not hovered
+    if ( !canvas.ready ) return;
+    const hover = document.elementFromPoint(event.clientX, event.clientY);
+    if ( !hover || (hover.id !== "board") ) return;
+    event.preventDefault();
+
+    // Identify scroll modifiers
+    const isCtrl = event.ctrlKey || event.metaKey;
+    const isShift = event.shiftKey;
+    const layer = canvas.activeLayer;
+
+    // Case 1 - rotate placeable objects
+    if ( layer?.options?.rotatableObjects && (isCtrl || isShift) ) {
+      const hasTarget = layer.options?.controllableObjects ? layer.controlled.length : !!layer.hover;
+      if ( hasTarget ) {
+        const t = Date.now();
+        if ( (t - this._wheelTime) < this.constructor.MOUSE_WHEEL_RATE_LIMIT ) return;
+        this._wheelTime = t;
+        return layer._onMouseWheel(event);
+      }
+    }
+
+    // Case 2 - zoom the canvas
+    canvas._onMouseWheel(event);
+  }
+}