Add mouseWheelZoomDelta option to MapOptions

externs/ol.js

@@ -70,6 +70,12 @@ olx.MapOptionsExtern.prototype.maxResolution;
 olx.MapOptionsExtern.prototype.mouseWheelZoom;
 
 
+/**
+ * @type {number|undefined}
+ */
+olx.MapOptionsExtern.prototype.mouseWheelZoomDelta;
+
+
 /**
  * @type {number|undefined}
  */

src/ol/interaction/mousewheelzoom.js

@@ -9,8 +9,15 @@ goog.require('ol.MapBrowserEvent');
 /**
  * @constructor
  * @extends {ol.interaction.Interaction}
+ * @param {number} delta The zoom delta applied on each mousewheel.
  */
-ol.interaction.MouseWheelZoom = function() {
+ol.interaction.MouseWheelZoom = function(delta) {
+  /**
+   * @private
+   * @type {number}
+   */
+  this.delta_ = delta;
+
   goog.base(this);
 };
 goog.inherits(ol.interaction.MouseWheelZoom, ol.interaction.Interaction);
@@ -28,12 +35,8 @@ ol.interaction.MouseWheelZoom.prototype.handleMapBrowserEvent =
         mapBrowserEvent.browserEvent;
     goog.asserts.assert(mouseWheelEvent instanceof goog.events.MouseWheelEvent);
     var anchor = mapBrowserEvent.getCoordinate();
-    var oldResolution = map.getResolution();
-    var factor = Math.exp(Math.log(2) / 4);
-    if (mouseWheelEvent.deltaY < 0) {
-      factor = 1 / factor;
-    }
-    map.zoomToResolution(oldResolution * factor, anchor);
+    var delta = mouseWheelEvent.deltaY < 0 ? this.delta_ : -this.delta_;
+    map.zoom(delta, anchor);
     mapBrowserEvent.preventDefault();
     mouseWheelEvent.preventDefault();
   }

src/ol/mapoptions.js

@@ -64,6 +64,7 @@ ol.DEFAULT_RENDERER_HINTS = [
  *            layers: (ol.Collection|undefined),
  *            maxResolution: (number|undefined),
  *            mouseWheelZoom: (boolean|undefined),
+ *            mouseWheelZoomDelta: (number|undefined),
  *            numZoomLevels: (number|undefined),
  *            projection: (ol.Projection|string|undefined),
  *            renderer: (ol.RendererHint|undefined),
@@ -241,7 +242,10 @@ ol.MapOptions.createInteractions_ = function(mapOptionsLiteral) {
   var mouseWheelZoom = goog.isDef(mapOptionsLiteral.mouseWheelZoom) ?
       mapOptionsLiteral.mouseWheelZoom : true;
   if (mouseWheelZoom) {
-    interactions.push(new ol.interaction.MouseWheelZoom());
+    var mouseWheelZoomDelta =
+        goog.isDef(mapOptionsLiteral.mouseWheelZoomDelta) ?
+            mapOptionsLiteral.mouseWheelZoomDelta : 1;
+    interactions.push(new ol.interaction.MouseWheelZoom(mouseWheelZoomDelta));
   }
 
   var shiftDragZoom = goog.isDef(mapOptionsLiteral.shiftDragZoom) ?

test/spec/ol/mapoptions.test.js

@@ -51,4 +51,47 @@ describe('ol.MapOptions', function() {
 
     });
   });
+
+  describe('create interactions', function() {
+
+    var options;
+
+    beforeEach(function() {
+      options = {
+          rotate: false,
+          doubleClickZoom: false,
+          dragPan: false,
+          keyboard: false,
+          mouseWheelZoom: false,
+          shiftDragZoom: false
+      };
+    });
+
+    describe('create mousewheel interaction', function() {
+
+      beforeEach(function() {
+        options.mouseWheelZoom = true;
+      });
+
+      describe('default mouseWheelZoomDelta', function() {
+        it('create mousewheel interaction with default delta', function() {
+          var interactions = ol.MapOptions.createInteractions_(options);
+          expect(interactions.getLength()).toEqual(1);
+          expect(interactions.getAt(0)).toBeA(ol.interaction.MouseWheelZoom);
+          expect(interactions.getAt(0).delta_).toEqual(1);
+        });
+      });
+
+      describe('set mouseWheelZoomDelta', function() {
+        it('create mousewheel interaction with default delta', function() {
+          options.mouseWheelZoomDelta = 7;
+          var interactions = ol.MapOptions.createInteractions_(options);
+          expect(interactions.getLength()).toEqual(1);
+          expect(interactions.getAt(0)).toBeA(ol.interaction.MouseWheelZoom);
+          expect(interactions.getAt(0).delta_).toEqual(7);
+        });
+      });
+    });
+  });
+
 });