"panTo should use tween if new center is in the current bounds + a ratio".

Add a bounds.scale method (takes a ratio and an optional center) and 
call it from the panTo to give a ratio we can pan inside of. Patch by
sbenthall, r=me,elemoine (Closes #1341) 


git-svn-id: http://svn.openlayers.org/trunk/openlayers@7678 dc9f47b5-9b13-0410-9fdd-eb0c1a62fdaf

lib/OpenLayers/BaseTypes/Bounds.js

@@ -219,6 +219,48 @@ OpenLayers.Bounds = OpenLayers.Class({
                                       (this.bottom + this.top) / 2);
     },
 
+    /**
+     * Method: scale
+     * Scales the bounds around a pixel or lonlat. Note that the new 
+     *     bounds may return non-integer properties, even if a pixel
+     *     is passed. 
+     * 
+     * Parameters:
+     * ratio - {Float} 
+     * origin - {<OpenLayers.Pixel> or <OpenLayers.LonLat>}
+     *          Default is center.
+     *
+     * Returns:
+     * {<OpenLayers.Bound>} A new bounds that is scaled by ratio
+     *                      from origin.
+     */
+
+    scale: function(ratio, origin){
+        if(origin == null){
+            origin = this.getCenterLonLat();
+        }
+
+        var bounds = [];
+        
+        var origx,origy;
+
+        // get origin coordinates
+        if(origin.CLASS_NAME == "OpenLayers.LonLat"){
+            origx = origin.lon;
+            origy = origin.lat;
+        } else {
+            origx = origin.x;
+            origy = origin.y;
+        }
+
+        var left = (this.left - origx) * ratio + origx;
+        var bottom = (this.bottom - origy) * ratio + origy;
+        var right = (this.right - origx) * ratio + origx;
+        var top = (this.top - origy) * ratio + origy;
+
+        return new OpenLayers.Bounds(left, bottom, right, top);
+    },
+
     /**
      * APIMethod: add
      * 

lib/OpenLayers/Map.js

@@ -196,6 +196,13 @@ OpenLayers.Map = OpenLayers.Class({
      */
     zoom: 0,    
 
+    /**
+     * Property: panRatio
+     * {Float} The ratio of the current extent within
+     *         which panning will tween.
+     */
+    panRatio: 1.5,    
+
     /**
      * Property: viewRequestID
      * {String} Used to store a unique identifier that changes when the map 
@@ -1368,7 +1375,7 @@ OpenLayers.Map = OpenLayers.Class({
      * lonlat - {<OpenLayers.Lonlat>}
      */
     panTo: function(lonlat) {
-        if (this.panMethod && this.getExtent().containsLonLat(lonlat)) {
+        if (this.panMethod && this.getExtent().scale(this.panRatio).containsLonLat(lonlat)) {
             if (!this.panTween) {
                 this.panTween = new OpenLayers.Tween(this.panMethod);
             }

tests/BaseTypes/Bounds.html

@@ -557,6 +557,25 @@
         t.ok(bounds == null, "returns null on erroneous add operation (null y)");
     }
 
+    function test_Bounds_scale(t) {
+        t.plan(3);
+
+        origBounds = new OpenLayers.Bounds(1,2,3,4);
+        bounds = origBounds.scale(2);  
+        var b = new OpenLayers.Bounds(0,1,4,5);
+        t.ok(bounds.equals(b), "Bounds scale correctly with default origin at center")
+
+        var origin = new OpenLayers.Pixel(0,1);
+        bounds = origBounds.scale(2,origin);
+        b = new OpenLayers.Bounds(2,3,6,7);
+        t.ok(bounds.equals(b), "Bounds scale correctly with offset origin");
+
+        origin = new OpenLayers.Pixel(5,1);
+        bounds = bounds.scale(2, origin);
+        b = new OpenLayers.Bounds(-1, 5, 7, 13);
+        t.ok(bounds.equals(b), "Bounds scale correctly with offset origin");
+
+    }
 
   </script>
 </head>