Merge pull request #5731 from Benjaki2/master

Added a pixelRatio adjust to the canvasTileLayer 'forEachLayerAtPixel…

src/ol/renderer/canvas/tilelayer.js

@@ -198,8 +198,9 @@ ol.renderer.canvas.TileLayer.prototype.forEachLayerAtPixel = function(
     pixel, frameState, callback, thisArg) {
   var canvas = this.context.canvas;
   var size = frameState.size;
-  canvas.width = size[0];
-  canvas.height = size[1];
+  var pixelRatio = frameState.pixelRatio;
+  canvas.width = size[0] * pixelRatio;
+  canvas.height = size[1] * pixelRatio;
   this.composeFrame(frameState, this.getLayer().getLayerState(), this.context);
 
   var imageData = this.context.getImageData(