add onEnter and onLeave callback functions to the DragFeature control, p=adube, r=me (closes #3034)

git-svn-id: http://svn.openlayers.org/trunk/openlayers@11071 dc9f47b5-9b13-0410-9fdd-eb0c1a62fdaf

lib/OpenLayers/Control/DragFeature.js

@@ -65,6 +65,28 @@ OpenLayers.Control.DragFeature = OpenLayers.Class(OpenLayers.Control, {
      */
     onComplete: function(feature, pixel) {},
 
+    /**
+     * APIProperty: onEnter
+     * {Function} Define this function if you want to know when the mouse
+     *     goes over a feature and thereby makes this feature a candidate
+     *     for dragging.
+     *
+     * Parameters:
+     * feature - {<OpenLayers.Feature.Vector>} The feature that is ready
+     *     to be dragged.
+     */
+    onEnter: function(feature) {},
+
+    /**
+     * APIProperty: onLeave
+     * {Function} Define this function if you want to know when the mouse
+     *     goes out of the feature that was dragged.
+     *
+     * Parameters:
+     * feature - {<OpenLayers.Feature.Vector>} The feature that was dragged.
+     */
+    onLeave: function(feature) {},
+
     /**
      * APIProperty: documentDrag
      * {Boolean} If set to true, mouse dragging will continue even if the
@@ -192,6 +214,7 @@ OpenLayers.Control.DragFeature = OpenLayers.Class(OpenLayers.Control, {
             this.handlers.drag.activate();
             this.over = true;
             OpenLayers.Element.addClass(this.map.viewPortDiv, this.displayClass + "Over");
+            this.onEnter(feature);
         } else {
             if(this.feature.id == feature.id) {
                 this.over = true;
@@ -269,6 +292,7 @@ OpenLayers.Control.DragFeature = OpenLayers.Class(OpenLayers.Control, {
             OpenLayers.Element.removeClass(
                 this.map.viewPortDiv, this.displayClass + "Over"
             );
+            this.onLeave(feature);
             this.feature = null;
         } else {
             if(this.feature.id == feature.id) {

tests/Control/DragFeature.html

@@ -71,11 +71,14 @@
     }
     
     function test_Control_DragFeature_over(t) {
-        t.plan(3);
+        t.plan(5);
+        var log = [];
         var map = new OpenLayers.Map("map");
         var layer = new OpenLayers.Layer.Vector();
         map.addLayer(layer);
-        var control = new OpenLayers.Control.DragFeature(layer);
+        var control = new OpenLayers.Control.DragFeature(layer, {
+            onEnter: function(f) { log.push({feature: f}); }
+        });
         map.addControl(control);
         
         control.activate();
@@ -94,6 +97,10 @@
              "control gets the proper feature from the feature handler");
         t.ok(control.handlers.drag.active,
              "drag handler activated when over a feature");
+        t.eq(log.length, 1,
+             "onEnter called exactly once");
+        t.eq(log[0].feature.id, feature.id,
+             "onEnter called with expected feature");
     }
 
     function test_Control_DragFeature_down(t) {
@@ -241,11 +248,14 @@
     }
 
     function test_Control_DragFeature_out(t) {
-        t.plan(2);
+        t.plan(4);
+        var log = [];
         var map = new OpenLayers.Map("map");
         var layer = new OpenLayers.Layer.Vector();
         map.addLayer(layer);
-        var control = new OpenLayers.Control.DragFeature(layer);
+        var control = new OpenLayers.Control.DragFeature(layer, {
+            onLeave: function(f) { log.push({feature: f}); }
+        });
         map.addControl(control);
 
         control.activate();
@@ -268,7 +278,10 @@
         map.events.triggerEvent("mousemove", {type: "mousemove"});
         t.ok(control.feature == null,
              "feature is set to null on mouse out");
-        
+        t.eq(log.length, 1,
+             "onLeave called exactly once");
+        t.eq(log[0].feature.id, feature.id,
+             "onLeave called with expected feature");
     }
 
     </script>