Add pixelRatio param to ol.Image constructor

src/ol/image.js

@@ -28,11 +28,13 @@ ol.ImageState = {
  * @extends {goog.events.EventTarget}
  * @param {ol.Extent} extent Extent.
  * @param {number} resolution Resolution.
+ * @param {number} pixelRatio Pixel ratio.
  * @param {string} src Image source URI.
  * @param {?string} crossOrigin Cross origin.
  * @param {Array.<ol.Attribution>} attributions Attributions.
  */
-ol.Image = function(extent, resolution, src, crossOrigin, attributions) {
+ol.Image =
+    function(extent, resolution, pixelRatio, src, crossOrigin, attributions) {
 
   goog.base(this);
 
@@ -54,6 +56,12 @@ ol.Image = function(extent, resolution, src, crossOrigin, attributions) {
    */
   this.src_ = src;
 
+  /**
+   * @private
+   * @type {number}
+   */
+  this.pixelRatio_ = pixelRatio;
+
   /**
    * @private
    * @type {number}
@@ -137,6 +145,14 @@ ol.Image.prototype.getImageElement = function(opt_context) {
 };
 
 
+/**
+ * @return {number} PixelRatio.
+ */
+ol.Image.prototype.getPixelRatio = function() {
+  return this.pixelRatio_;
+};
+
+
 /**
  * @return {number} Resolution.
  */

src/ol/source/imagesource.js

@@ -89,7 +89,7 @@ ol.source.Image.prototype.createImage =
   var imageUrl = this.imageUrlFunction(extent, size, projection);
   if (goog.isDef(imageUrl)) {
     image = new ol.Image(
-        extent, resolution, imageUrl, this.crossOrigin_,
+        extent, resolution, pixelRatio, imageUrl, this.crossOrigin_,
         this.getAttributions());
   }
   return image;

src/ol/source/imagewmssource.js

@@ -75,6 +75,7 @@ ol.source.ImageWMS.prototype.getImage =
   var image = this.image_;
   if (!goog.isNull(image) &&
       image.getResolution() == resolution &&
+      image.getPixelRatio() == pixelRatio &&
       ol.extent.containsExtent(image.getExtent(), extent)) {
     return image;
   }

src/ol/source/mapguidesource.js

@@ -78,6 +78,7 @@ ol.source.MapGuide.prototype.getImage =
   var image = this.image_;
   if (!goog.isNull(image) &&
       image.getResolution() == resolution &&
+      image.getPixelRatio() == pixelRatio &&
       ol.extent.containsExtent(image.getExtent(), extent)) {
     return image;
   }