establish generic getExtent() function in Layer. Move resolution-based calculation up into Grid.js. This prevents infinite loops and is more useful to generic layers like Gmaps, VE, etc.

git-svn-id: http://svn.openlayers.org/trunk/openlayers@950 dc9f47b5-9b13-0410-9fdd-eb0c1a62fdaf
2006-07-16 16:55:20 +00:00
parent 629e62b82b
commit 3776a5d729
2 changed files with 57 additions and 40 deletions
@@ -263,6 +263,33 @@ OpenLayers.Layer.Grid.prototype =
        return maxRes / Math.pow(2, zoom);
    },
    
+    /** Calculates based on resolution, center, and mapsize
+     * 
+     * @returns A Bounds object which represents the lon/lat bounds of the 
+     *          current viewPort.
+     * @type OpenLayers.Bounds
+     */
+    getExtent: function () {
+        var extent = null;
+
+        var center = this.map.getCenter();
+        if (center != null) {
+
+ 	            var res = this.getResolution();
+ 	            var size = this.map.getSize();
+ 	            var w_deg = size.w * res;
+ 	            var h_deg = size.h * res;
+
+ 	            return new OpenLayers.Bounds(center.lon - w_deg / 2,
+                         	                 center.lat - h_deg / 2,
+                         	                 center.lon + w_deg / 2,
+                          	                 center.lat + h_deg / 2);
+
+        }
+
+        return extent;
+    },
+    
    /**
     * @param {OpenLayers.Bounds} bounds
     *