allow google layer to be configured with min/max zoomLevels. update example.

git-svn-id: http://svn.openlayers.org/branches/openlayers/2.0@1308 dc9f47b5-9b13-0410-9fdd-eb0c1a62fdaf

lib/OpenLayers/Layer/Google.js

@@ -49,7 +49,10 @@ OpenLayers.Layer.Google.prototype =
   // OPTIONS
 
     /** @type int */
-    numZoomLevels: 16,
+    minZoomLevel: 0,
+    
+    /** @type int */
+    maxZoomLevel: 16,
 
     
     /** 
@@ -62,6 +65,8 @@ OpenLayers.Layer.Google.prototype =
         if (this.maxExtent == null) {
             this.maxExtent = new OpenLayers.Bounds(-180, -90, 180, 90);
         }
+        
+        this.numZoomLevels = this.maxZoomLevel - this.minZoomLevel + 1;
     },
     
     /**
@@ -263,6 +268,12 @@ OpenLayers.Layer.Google.prototype =
         if ((this.gmap != null) && (this.gmap.getCenter() != null)) {
             var gBounds = this.getGLatLngBoundsFromOLBounds(bounds);
             var gZoom = this.gmap.getBoundsZoomLevel(gBounds);
+
+            //make sure zoom is within bounds    
+            var gZoom = Math.min(Math.max(gZoom, this.minZoomLevel), 
+                                 this.maxZoomLevel);
+         
+
             zoom = this.getOLZoomFromGZoom(gZoom);
         }
         return zoom;
@@ -291,7 +302,7 @@ OpenLayers.Layer.Google.prototype =
     getOLZoomFromGZoom: function(gZoom) {
         var zoom = null;
         if (gZoom != null) {
-            zoom = gZoom;
+            zoom = gZoom - this.minZoomLevel;
         }
         return zoom;
     },
@@ -306,7 +317,7 @@ OpenLayers.Layer.Google.prototype =
     getGZoomFromOLZoom: function(olZoom) {
         var zoom = null; 
         if (olZoom != null) {
-            zoom = olZoom;
+            zoom = olZoom + this.minZoomLevel;
         }
         return zoom;
     },