mousewheel zooms on mouse position. patch from #341. thanks frederic \!

git-svn-id: http://svn.openlayers.org/trunk/openlayers@1945 dc9f47b5-9b13-0410-9fdd-eb0c1a62fdaf

lib/OpenLayers/Control/MouseDefaults.js

@@ -94,6 +94,9 @@ OpenLayers.Control.MouseDefaults.prototype =
     * @param {Event} evt
     */
     defaultMouseMove: function (evt) {
+        // record the mouse position, used in onWheelEvent
+        this.mousePosition = evt.xy.clone();
+
         if (this.mouseDragStart != null) {
             if (this.zoomBox) {
                 var deltaX = Math.abs(this.mouseDragStart.x - evt.xy.x);
@@ -155,15 +158,21 @@ OpenLayers.Control.MouseDefaults.prototype =
     /** User spun scroll wheel up
      * 
      */
-    defaultWheelUp: function()  {
+    defaultWheelUp: function(evt) {
-        this.map.zoomIn();
+        if (this.map.getZoom() <= this.map.getNumZoomLevels()) {
+            this.map.setCenter(this.map.getLonLatFromPixel(evt.xy),
+                               this.map.getZoom() + 1);
+        }
     },
 
     /** User spun scroll wheel down
      * 
      */
-    defaultWheelDown: function()  {
+    defaultWheelDown: function(evt) {
-        this.map.zoomOut();
+        if (this.map.getZoom() > 0) {
+            this.map.setCenter(this.map.getLonLatFromPixel(evt.xy),
+                               this.map.getZoom() - 1);
+        }
     },
 
     /** Zoombox function. 
@@ -238,10 +247,15 @@ OpenLayers.Control.MouseDefaults.prototype =
                 delta = -e.detail / 3;
             }
             if (delta) {
+                // add the mouse position to the event because mozilla has a bug
+                // with clientX and clientY (see https://bugzilla.mozilla.org/show_bug.cgi?id=352179)
+                // getLonLatFromViewPortPx(e) returns wrong values
+                e.xy = this.mousePosition;
+
                 if (delta < 0) {
-                   this.defaultWheelDown();
+                   this.defaultWheelDown(e);
                 } else {
-                   this.defaultWheelUp();
+                   this.defaultWheelUp(e);
                 }
             }