new function to create an alpha-transparency protected image -- burried in a div. This is for Ticket #25

git-svn-id: http://svn.openlayers.org/trunk/openlayers@362 dc9f47b5-9b13-0410-9fdd-eb0c1a62fdaf

lib/OpenLayers/Util.js

@@ -670,6 +670,45 @@ OpenLayers.Util.createImage = function(img, sz, xy, position, id, border) {
     return image;
 };
 
+/** 
+* @param {String} imgURL
+* @param {OpenLayers.Size} sz
+* @param {OpenLayers.Pixel} px
+* @param {String} position
+* @param {String} id
+* @param {int} border
+*
+* @returns A DOM Div created with a DOM Image inside it. If the hack is 
+*           needed for transparency in IE, it is added.
+* @type DOMElement
+*/ 
+OpenLayers.Util.createAlphaImageDiv = function(imgURL, sz, px, position, 
+                                               id, border) {
+
+    var div = OpenLayers.Util.createDiv(id, px, sz);
+    var img = OpenLayers.Util.createImage(imgURL, sz, null, "relative",
+                                               id + "innerImage", border);
+    div.appendChild(img);
+
+        
+    var arVersion = navigator.appVersion.split("MSIE");
+    var version = parseFloat(arVersion[1]);
+    
+    var alphaHack = ( (document.body.filters) &&
+                      (version >= 5.5) && (version < 7) );
+
+    if (alphaHack) {
+        div.style.display = "inline-block";
+        div.style.filter = "progid:DXImageTransform.Microsoft" +
+                                 ".AlphaImageLoader(src='" + imgURL + "')";
+        img.style.filter = "progid:DXImageTransform.Microsoft" +
+                                ".Alpha(opacity=0)";
+        img.width = img.style.width;
+        img.height = img.style.height;
+    }
+
+    return div;
+};
 
 /**
 * @param {Object} params