refactor range checking into map and store a state variable in layer so that we dont fire changelayer every time user zooms

git-svn-id: http://svn.openlayers.org/trunk/openlayers@1606 dc9f47b5-9b13-0410-9fdd-eb0c1a62fdaf

lib/OpenLayers/Layer.js

@@ -47,6 +47,14 @@ OpenLayers.Layer.prototype = {
      */
     visibility: true,
 
+    /** Whether or not the map's current resolution is within this layer's
+     *   min/max range -- this is set in map's setCenter() whenever zoom
+     *   changes
+     * 
+     * @type Boolean
+     */
+    inRange: false,
+
   // OPTIONS
 
     /** @type Array */
@@ -186,10 +194,7 @@ OpenLayers.Layer.prototype = {
      * @param {Boolean} dragging
      */
     moveTo:function(bounds, zoomChanged, dragging) {
-        if (zoomChanged) {
-            this.display(this.visibility && this.inRange());
-            this.map.events.triggerEvent("changelayer");
-        }
+        this.display(this.visibility && this.inRange);
     },
 
     /** Set the map property for the layer. This is done through an accessor
@@ -266,7 +271,7 @@ OpenLayers.Layer.prototype = {
      *          current resolution
      * @type Boolean
      */
-    inRange: function() {
+    calculateInRange: function() {
         var inRange = false;
         if (this.map) {
             var resolution = this.map.getResolution();