More APIdoc for OpenLayers.Tile.Image.getCanvasContext

lib/OpenLayers/Tile/Image.js

@@ -425,6 +425,15 @@ OpenLayers.Tile.Image = OpenLayers.Class(OpenLayers.Tile, {
      * Returns undefined if the browser does not support canvas, if
      * the tile has no image or if it's currently loading.
      *
+     * The function returns a canvas context instance but the
+     * underlying canvas is still available in the 'canvas' property:
+     * (code)
+     * var context = tile.getCanvasContext();
+     * if (context) {
+     *     var data = context.canvas.toDataURL('image/jpeg');
+     * }
+     * (end)
+     *
      * Returns:
      * {Boolean}
      */