New fontOpacity option for vector feature style. r=pgiraud (closes #2438)

git-svn-id: http://svn.openlayers.org/trunk/openlayers@9978 dc9f47b5-9b13-0410-9fdd-eb0c1a62fdaf

examples/symbolizers-fill-stroke-graphic.html

@@ -51,7 +51,9 @@
                                     stroke: true,
                                     fill: false,
                                     label: "Point without fill",
-                                    labelAlign: "rb"
+                                    labelAlign: "rb",
+                                    fontColor: "#ff0000",
+                                    fontOpacity: 0.4
                                 },
                                 filter: new OpenLayers.Filter.Comparison({
                                     type: "==",

lib/OpenLayers/Feature/Vector.js

@@ -362,6 +362,7 @@ OpenLayers.Feature.Vector = OpenLayers.Class(OpenLayers.Feature, {
  * labelSelect - {Boolean} If set to true, labels will be selectable using SelectFeature or similar controls.
  *     Default is false.
  * fontColor - {String} The font color for the label, to be provided like CSS.
+ * fontOpacity - {Number} Opacity (0-1) for the label
  * fontFamily - {String} The font family for the label, to be provided like in CSS.
  * fontSize - {String} The font size for the label, to be provided like in CSS.
  * fontWeight - {String} The font weight for the label, to be provided like in CSS.

lib/OpenLayers/Renderer/Canvas.js

@@ -365,7 +365,7 @@ OpenLayers.Renderer.Canvas = OpenLayers.Class(OpenLayers.Renderer, {
         
         this.setCanvasStyle("reset");
         this.canvas.fillStyle = style.fontColor;
-        this.canvas.globalAlpha = 1;
+        this.canvas.globalAlpha = style.fontOpacity || 1.0;
         var fontStyle = style.fontWeight + " " + style.fontSize + " " + style.fontFamily;
         if (this.canvas.fillText) {
             // HTML5

lib/OpenLayers/Renderer/SVG.js

@@ -702,6 +702,9 @@ OpenLayers.Renderer.SVG = OpenLayers.Class(OpenLayers.Renderer.Elements, {
         if (style.fontColor) {
             label.setAttributeNS(null, "fill", style.fontColor);
         }
+        if (style.fontOpacity) {
+            label.setAttributeNS(null, "opacity", style.fontOpacity);
+        }
         if (style.fontFamily) {
             label.setAttributeNS(null, "font-family", style.fontFamily);
         }

lib/OpenLayers/Renderer/VML.js

@@ -810,6 +810,9 @@ OpenLayers.Renderer.VML = OpenLayers.Class(OpenLayers.Renderer.Elements, {
         if (style.fillColor) {
             textbox.style.color = style.fontColor;
         }
+        if (style.fontOpacity) {
+            textbox.style.filter = 'alpha(opacity=' + (style.fontOpacity * 100) + ')';
+        }
         if (style.fontFamily) {
             textbox.style.fontFamily = style.fontFamily;
         }