Commit scale-based methods back into trunk. Layers or Maps now support setting

a list of scales or resolutions in the options to the constructor, from which
resolutions are calculated. Map now has a 'setScale' function which will allow
you to zoom to as close to a given scale as possible.


git-svn-id: http://svn.openlayers.org/trunk/openlayers@1171 dc9f47b5-9b13-0410-9fdd-eb0c1a62fdaf

lib/OpenLayers/Layer.js

@@ -54,7 +54,15 @@ OpenLayers.Layer.prototype = {
     
     /** @type int */
     maxZoomLevel: null,
+   
+    /** @type float */
+    minScale: null,
     
+    /** @type float */
+    maxScale: null,
+    
+    /** @type String */
+    units: null,
     
     /**
      * @constructor
@@ -162,6 +170,20 @@ OpenLayers.Layer.prototype = {
      */
     setMap: function(map) {
         this.map = map;
+        
+        var properties = new Array(
+          'projection', 'minExtent', 'maxExtent',
+          'minScale', 'maxScale',
+          'maxResolution', 'minResolution', 
+          'minZoomLevel', 'maxZoomLevel', 'units',
+          'scales', 'resolutions'
+          
+        );
+        for(var i=0; i < properties.length; i++) {
+            if (this[properties[i]] == null) {
+                this[properties[i]] = this.map[properties[i]];
+            }    
+        }
     },
   
     /**