Basic support for canvas only (patch from trac #3503)

lib/OpenLayers/Feature/Vector.js

@@ -419,6 +419,8 @@ OpenLayers.Feature.Vector = OpenLayers.Class(OpenLayers.Feature, {
  * labelYOffset - {Number} Pixel offset along the positive y axis for displacing the label. Not supported by the canvas renderer.
  * labelSelect - {Boolean} If set to true, labels will be selectable using SelectFeature or similar controls.
  *     Default is false.
+ * labelOutlineColor - {String} The color of the label outline. Default is 'white'. Only supported by the canvas renderer.
+ * labelOutlineWidth - {Number} The width of the label outline. Default is 3, set to 0 or null to disable. Only supported by the canvas renderer.
  * 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.

lib/OpenLayers/Renderer/Canvas.js

@@ -527,7 +527,9 @@ OpenLayers.Renderer.Canvas = OpenLayers.Class(OpenLayers.Renderer, {
     drawText: function(location, style) {
         style = OpenLayers.Util.extend({
             fontColor: "#000000",
-            labelAlign: "cm"
+            labelAlign: "cm",
+            labelOutlineColor: "white",
+            labelOutlineWidth: 3
         }, style);
         var pt = this.getLocalXY(location);
 
@@ -560,6 +562,13 @@ OpenLayers.Renderer.Canvas = OpenLayers.Class(OpenLayers.Renderer, {
                 this.canvas.measureText('xx').width;
             pt[1] += lineHeight*vfactor*(numRows-1);
             for (var i = 0; i < numRows; i++) {
+                if (style.labelOutlineWidth) {
+                    this.canvas.save();
+                    this.canvas.strokeStyle = style.labelOutlineColor;
+                    this.canvas.lineWidth = style.labelOutlineWidth;
+                    this.canvas.strokeText(labelRows[i], pt[0], pt[1] + (lineHeight*i));
+                    this.canvas.restore();
+                }
                 this.canvas.fillText(labelRows[i], pt[0], pt[1] + (lineHeight*i));
             }
         } else if (this.canvas.mozDrawText) {