patch for improved mousedragging. We were able to test this on my eeepc

and get a very obvious speedup in performance. This adds a configurable
'interval' to the dragpan control (and an interval to the 'drag' control,
defaulting to 0px). Patch put together by tcoulter. (Closes #1509) 


git-svn-id: http://svn.openlayers.org/trunk/openlayers@7608 dc9f47b5-9b13-0410-9fdd-eb0c1a62fdaf

lib/OpenLayers/Control/DragPan.js

@@ -28,14 +28,27 @@ OpenLayers.Control.DragPan = OpenLayers.Class(OpenLayers.Control, {
      */
     panned: false,
     
+    /**
+     * Property: interval
+     * The number of milliseconds that should ellapse before
+     * panning the map again. Set this to increase dragging performance.
+     * Defaults to 25 milliseconds.
+     */
+    interval: 25, 
+    
     /**
      * Method: draw
      * Creates a Drag handler, using <panMap> and
      * <panMapDone> as callbacks.
      */    
     draw: function() {
-        this.handler = new OpenLayers.Handler.Drag(this,
-                            {"move": this.panMap, "done": this.panMapDone});
+        this.handler = new OpenLayers.Handler.Drag(this, {
+                "move": this.panMap,
+                "done": this.panMapDone
+            }, {
+                interval: this.interval
+            }
+        );
     },
 
     /**

lib/OpenLayers/Control/Navigation.js

@@ -30,6 +30,12 @@ OpenLayers.Control.Navigation = OpenLayers.Class(OpenLayers.Control, {
      */
     dragPan: null,
 
+    /**
+     * APIProprety: dragPanOptions
+     * Options passed to the DragPan control.
+     */
+    dragPanOptions: null,
+
     /** 
      * Property: zoomBox
      * {<OpenLayers.Control.ZoomBox>}
@@ -41,7 +47,7 @@ OpenLayers.Control.Navigation = OpenLayers.Class(OpenLayers.Control, {
      * {Boolean} Whether the mousewheel should zoom the map
      */
     zoomWheelEnabled: true, 
-
+    
     /**
      * Constructor: OpenLayers.Control.Navigation
      * Create a new navigation control
@@ -110,7 +116,9 @@ OpenLayers.Control.Navigation = OpenLayers.Class(OpenLayers.Control, {
                                           'double': true, 
                                           'stopDouble': true
                                         });
-        this.dragPan = new OpenLayers.Control.DragPan({map: this.map});
+        this.dragPan = new OpenLayers.Control.DragPan(
+            OpenLayers.Util.extend({map: this.map}, this.dragPanOptions)
+        );
         this.zoomBox = new OpenLayers.Control.ZoomBox(
                     {map: this.map, keyMask: OpenLayers.Handler.MOD_SHIFT});
         this.dragPan.draw();