bringing all changes from sandbox/euzuro/LayersReworking down into the trunk. this is a merge of r656:HEAD http://svn.openlayers.org/sandbox/euzuro/LayersReworking

git-svn-id: http://svn.openlayers.org/trunk/openlayers@806 dc9f47b5-9b13-0410-9fdd-eb0c1a62fdaf

lib/OpenLayers/Layer/WMS.js

@@ -24,16 +24,17 @@ OpenLayers.Layer.WMS.prototype =
     * @param {str} name
     * @param {str} url
     * @param {hash} params
+    * @param {Object} options Hash of extra options to tag onto the layer
     */
-    initialize: function(name, url, params) {
+    initialize: function(name, url, params, options) {
         var newArguments = new Array();
         if (arguments.length > 0) {
             //uppercase params
             params = OpenLayers.Util.upperCaseObject(params);
-            newArguments.push(name, url, params);
+            newArguments.push(name, url, params, options);
         }
         OpenLayers.Layer.Grid.prototype.initialize.apply(this, newArguments);
-        
+
         if (arguments.length > 0) {
             OpenLayers.Util.applyDefaults(
                            this.params, 
@@ -43,7 +44,7 @@ OpenLayers.Layer.WMS.prototype =
     },    
 
     
-    /** WFS layer is never a base class. 
+    /** WMS layer is never a base class. 
      * @type Boolean
      */
     isBaseLayer: function() {
@@ -86,6 +87,49 @@ OpenLayers.Layer.WMS.prototype =
                                              url, this.tileSize);
     },
 
+
+
+    /** 
+     * @returns Degrees per Pixel
+     * @type float
+     */
+    getResolution: function() {
+        var maxRes = this.map.getMaxResolution();
+        var zoom = this.map.getZoom();
+
+        return maxRes / Math.pow(2, zoom);
+    },
+
+    /**
+    * @param {OpenLayers.Bounds} bounds
+    *
+    * @return {int}
+    */
+    getZoomForExtent: function (bounds) {
+
+        var maxRes = this.map.getMaxResolution();
+        var viewSize = this.map.getSize();
+
+        var width = bounds.getWidth();
+        var height = bounds.getHeight();
+
+        var degPerPixel = (width > height) ? width / viewSize.w 
+                                           : height / viewSize.h;
+        
+        var zoom = Math.floor( (Math.log(maxRes/degPerPixel)) / Math.log(2) );
+
+        var maxZoomLevel = this.map.getMaxZoomLevel();
+        var minZoomLevel = this.map.getMinZoomLevel();
+    
+        //make sure zoom is within bounds    
+        zoom = Math.min( Math.max(zoom, minZoomLevel), 
+                         maxZoomLevel );
+
+        return zoom;
+    },
+
+
+    
     /** @final @type String */
     CLASS_NAME: "OpenLayers.Layer.WMS"
 });