Merge pull request #3969 from samuellapointe/MouseZoomSimple

Add an option to use the mouse's location as an anchor when zooming

externs/olx.js

@@ -2648,7 +2648,8 @@ olx.interaction.ModifyOptions.prototype.wrapX;
 
 
 /**
- * @typedef {{duration: (number|undefined)}}
+ * @typedef {{duration: (number|undefined),
+ *     useAnchor: (boolean|undefined)}}
  * @api
  */
 olx.interaction.MouseWheelZoomOptions;
@@ -2662,6 +2663,16 @@ olx.interaction.MouseWheelZoomOptions;
 olx.interaction.MouseWheelZoomOptions.prototype.duration;
 
 
+/**
+ * Enable zooming using the mouse's location as the anchor. Default is `true`.
+ * When set to false, zooming in and out will zoom to the center of the screen
+ * instead of zooming on the mouse's location.
+ * @type {boolean|undefined}
+ * @api
+ */
+olx.interaction.MouseWheelZoomOptions.prototype.useAnchor;
+
+
 /**
  * @typedef {{threshold: (number|undefined),
  *     duration: (number|undefined)}}

src/ol/interaction/mousewheelzoominteraction.js

@@ -39,6 +39,13 @@ ol.interaction.MouseWheelZoom = function(opt_options) {
    */
   this.duration_ = goog.isDef(options.duration) ? options.duration : 250;
 
+  /**
+   * @private
+   * @type {boolean}
+   */
+  this.useAnchor_ = goog.isDef(options.useAnchor) ?
+      options.useAnchor : true;
+
   /**
    * @private
    * @type {?ol.Coordinate}
@@ -78,7 +85,10 @@ ol.interaction.MouseWheelZoom.handleEvent = function(mapBrowserEvent) {
     goog.asserts.assertInstanceof(mouseWheelEvent, goog.events.MouseWheelEvent,
         'mouseWheelEvent should be of type MouseWheelEvent');
 
-    this.lastAnchor_ = mapBrowserEvent.coordinate;
+    if (this.useAnchor_) {
+      this.lastAnchor_ = mapBrowserEvent.coordinate;
+    }
+
     this.delta_ += mouseWheelEvent.deltaY;
 
     if (!goog.isDef(this.startTime_)) {
@@ -119,3 +129,17 @@ ol.interaction.MouseWheelZoom.prototype.doZoom_ = function(map) {
   this.startTime_ = undefined;
   this.timeoutId_ = undefined;
 };
+
+
+/**
+ * Enable or disable using the mouse's location as an anchor when zooming
+ * @param {boolean} useAnchor true to zoom to the mouse's location, false
+ * to zoom to the center of the map
+ * @api
+ */
+ol.interaction.MouseWheelZoom.prototype.setMouseAnchor = function(useAnchor) {
+  this.useAnchor_ = useAnchor;
+  if (!useAnchor) {
+    this.lastAnchor_ = null;
+  }
+};

test/spec/ol/map.test.js

@@ -243,6 +243,9 @@ describe('ol.Map', function() {
         var interactions = ol.interaction.defaults(options);
         expect(interactions.getLength()).to.eql(1);
         expect(interactions.item(0)).to.be.a(ol.interaction.MouseWheelZoom);
+        expect(interactions.item(0).useAnchor_).to.eql(true);
+        interactions.item(0).setMouseAnchor(false);
+        expect(interactions.item(0).useAnchor_).to.eql(false);
       });
     });