From 944219ad8a80cd8df9182b478eb22c258523f64d Mon Sep 17 00:00:00 2001
From: Yury Delendik <ydelendik@mozilla.com>
Date: Thu, 13 Feb 2014 08:37:19 -0600
Subject: [PATCH] Balance smask process chunking

---
 src/display/canvas.js | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/display/canvas.js b/src/display/canvas.js
index 96ba5b825..e7a29afa5 100644
--- a/src/display/canvas.js
+++ b/src/display/canvas.js
@@ -652,7 +652,8 @@ var CanvasGraphics = (function CanvasGraphicsClosure() {
     }
 
     // processing image in chunks to save memory
-    var chunkSize = 16;
+    var PIXELS_TO_PROCESS = 65536;
+    var chunkSize = Math.min(height, Math.ceil(PIXELS_TO_PROCESS / width));
     for (var row = 0; row < height; row += chunkSize) {
       var chunkHeight = Math.min(chunkSize, height - row);
       var maskData = maskCtx.getImageData(0, row, width, chunkHeight);