From 5c76cb01afe62b4a9d5f26f41b9c428bc7a25cb3 Mon Sep 17 00:00:00 2001
From: Andreas Hocevar <andreas.hocevar@gmail.com>
Date: Wed, 4 May 2016 17:13:27 -0400
Subject: [PATCH 1/2] Use a snapshot of the frameState extent

---
 src/ol/source/rastersource.js | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/src/ol/source/rastersource.js b/src/ol/source/rastersource.js
index 9f1a5c1dbb..bbae4bc9d1 100644
--- a/src/ol/source/rastersource.js
+++ b/src/ol/source/rastersource.js
@@ -219,15 +219,16 @@ ol.source.Raster.prototype.getImage = function(extent, resolution, pixelRatio, p
     return null;
   }
 
-  if (!this.isDirty_(extent, resolution)) {
+  var currentExtent = extent.slice();
+  if (!this.isDirty_(currentExtent, resolution)) {
     return this.renderedImageCanvas_;
   }
 
   var context = this.canvasContext_;
   var canvas = context.canvas;
 
-  var width = Math.round(ol.extent.getWidth(extent) / resolution);
-  var height = Math.round(ol.extent.getHeight(extent) / resolution);
+  var width = Math.round(ol.extent.getWidth(currentExtent) / resolution);
+  var height = Math.round(ol.extent.getHeight(currentExtent) / resolution);
 
   if (width !== canvas.width ||
       height !== canvas.height) {
@@ -235,16 +236,16 @@ ol.source.Raster.prototype.getImage = function(extent, resolution, pixelRatio, p
     canvas.height = height;
   }
 
-  var frameState = this.updateFrameState_(extent, resolution, projection);
+  var frameState = this.updateFrameState_(currentExtent, resolution, projection);
 
   var imageCanvas = new ol.ImageCanvas(
-      extent, resolution, 1, this.getAttributions(), canvas,
+      currentExtent, resolution, 1, this.getAttributions(), canvas,
       this.composeFrame_.bind(this, frameState));
 
   this.renderedImageCanvas_ = imageCanvas;
 
   this.renderedState_ = {
-    extent: extent,
+    extent: currentExtent,
     resolution: resolution,
     revision: this.getRevision()
   };

From 39087b2fa482294f61e019c266f7d47a9a80829f Mon Sep 17 00:00:00 2001
From: Andreas Hocevar <andreas.hocevar@gmail.com>
Date: Wed, 4 May 2016 17:14:05 -0400
Subject: [PATCH 2/2] Reuse the frameState extent

---
 src/ol/map.js | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/src/ol/map.js b/src/ol/map.js
index f3327ae40d..6d860ac42c 100644
--- a/src/ol/map.js
+++ b/src/ol/map.js
@@ -1283,6 +1283,7 @@ ol.Map.prototype.renderFrame_ = function(time) {
 
   var size = this.getSize();
   var view = this.getView();
+  var extent = ol.extent.createEmpty();
   /** @type {?olx.FrameState} */
   var frameState = null;
   if (size !== undefined && ol.size.hasArea(size) && view && view.isDef()) {
@@ -1297,7 +1298,7 @@ ol.Map.prototype.renderFrame_ = function(time) {
       animate: false,
       attributions: {},
       coordinateToPixelMatrix: this.coordinateToPixelMatrix_,
-      extent: null,
+      extent: extent,
       focus: !this.focus_ ? viewState.center : this.focus_,
       index: this.frameIndex_++,
       layerStates: layerStates,
@@ -1329,7 +1330,7 @@ ol.Map.prototype.renderFrame_ = function(time) {
     preRenderFunctions.length = n;
 
     frameState.extent = ol.extent.getForViewAndSize(viewState.center,
-        viewState.resolution, viewState.rotation, frameState.size);
+        viewState.resolution, viewState.rotation, frameState.size, extent);
   }
 
   this.frameState_ = frameState;