Tile opacity patch from tschaub: Fix for #235. Also includes tests to ensure

that code works.


git-svn-id: http://svn.openlayers.org/trunk/openlayers@1433 dc9f47b5-9b13-0410-9fdd-eb0c1a62fdaf

lib/OpenLayers/Layer.js

@@ -436,6 +436,18 @@ OpenLayers.Layer.prototype = {
                        );    
     },
     
+    /**
+     * Sets the opacity for the entire layer (all images)
+     * @param {Float} opacity
+     */
+    setOpacity: function(opacity) {
+        this.opacity = opacity;
+        for(var i=0; i<this.div.childNodes.length; ++i) {
+            var element = this.div.childNodes[i];
+            OpenLayers.Util.setOpacity(element, opacity);
+        }
+    },
+
     /** @final @type String */
     CLASS_NAME: "OpenLayers.Layer"
 };

lib/OpenLayers/Tile/Image.js

@@ -102,6 +102,9 @@ OpenLayers.Tile.Image.prototype =
                                                       true);
         }
         this.layer.div.appendChild(this.imgDiv);
+        if(this.layer.opacity != null) {
+            OpenLayers.Util.setOpacity(this.imgDiv, this.layer.opacity);
+        }
     },
 
     /** @final @type String */

lib/OpenLayers/Util.js

@@ -125,6 +125,19 @@ OpenLayers.Util.createImage = function(id, px, sz, imgURL, position, border,
     return image;
 };
 
+/**
+ * Set the opacity of a DOM Element
+ * Note that for this function to work in IE, elements must "have layout"
+ * according to:
+ * http://msdn.microsoft.com/workshop/author/dhtml/reference/properties/haslayout.asp
+ *
+ * @param {DOMElement} element Set the opacity on this DOM element
+ * @param {Float} opacity Opacity value (0.0 - 1.0)
+ */
+OpenLayers.Util.setOpacity = function(element, opacity) {
+    element.style.opacity = opacity;
+    element.style.filter = 'alpha(opacity=' + (opacity * 100) + ')';
+}
 
 OpenLayers.Util.onImageLoad = function() {
     this.style.backgroundColor = null;

tests/test_Layer_WMS.html

@@ -150,6 +150,31 @@
  
     }
 
+    function test_08_Layer_WMS_setOpacity (t) {
+        t.plan( 5 );
+
+        var map = new OpenLayers.Map('map');
+        map.projection = "xx";
+        tUrl = "http://octo.metacarta.com/cgi-bin/mapserv";
+        tParams = { layers: 'basic', 
+                   format: 'image/png'};
+        tOptions = { 'opacity': '0.5' };           
+        var tLayer = new OpenLayers.Layer.WMS(name, tUrl, tParams, tOptions);
+        map.addLayer(tLayer);
+        map.zoomToMaxExtent();
+        t.eq(tLayer.opacity, "0.5", "Opacity is set correctly");
+        t.eq(tLayer.div.firstChild.style.opacity, "0.5", "Opacity on tile is correct");
+        tLayer.setOpacity("0.6");
+        t.eq(tLayer.opacity, "0.6", "setOpacity works properly");
+        t.eq(tLayer.div.firstChild.style.opacity, "0.6", "Opacity on tile is changed correctly");
+        var pixel = new OpenLayers.Pixel(5,6);
+        var tile = tLayer.addTile(new OpenLayers.Bounds(1,2,3,4), pixel);
+        tile.draw();
+        t.eq(tile.imgDiv.style.opacity, "0.6", "Tile opacity is set correctly");
+
+    }    
+        
+    
     function test_99_Layer_WMS_destroy (t) {
 
         t.plan( 1 );