Add getDataExtent to Vector Layer. Patch from rupert, tests by me, r=me

(Closes #1369)


git-svn-id: http://svn.openlayers.org/trunk/openlayers@6947 dc9f47b5-9b13-0410-9fdd-eb0c1a62fdaf

lib/OpenLayers/Layer/Vector.js

@@ -534,5 +534,24 @@ OpenLayers.Layer.Vector = OpenLayers.Class(OpenLayers.Layer, {
     preFeatureInsert: function(feature) {
     },
 
+    /** 
+     * APIMethod: getDataExtent
+     * Calculates the max extent which includes all of the features.
+     * 
+     * Returns:
+     * {<OpenLayers.Bounds>}
+     */
+    getDataExtent: function () {
+        var maxExtent = null;
+        if( this.features && (this.features.length > 0)){
+            var maxExtent = this.features[0].geometry.getBounds();
+            for(var i=0; i < this.features.length; i++){
+                maxExtent.extend(this.features[i].geometry.getBounds());
+            }
+        }
+
+        return maxExtent;
+    },
+
     CLASS_NAME: "OpenLayers.Layer.Vector"
 });