From 97cc06a7f95ea6c25c6699b85a6f746b3ca00cba Mon Sep 17 00:00:00 2001
From: Nicholas Nethercote <nnethercote@mozilla.com>
Date: Thu, 12 Jun 2014 16:20:30 +1000
Subject: [PATCH] Zero the height and width of the PageView canvas before
 deleting.

---
 web/page_view.js | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/web/page_view.js b/web/page_view.js
index 47b18d7d3..d90419e55 100644
--- a/web/page_view.js
+++ b/web/page_view.js
@@ -99,7 +99,13 @@ var PageView = function pageView(container, id, scale,
       this.annotationLayer = null;
     }
 
-    delete this.canvas;
+    if (this.canvas) {
+      // Zeroing the width and height causes Firefox to release graphics
+      // resources immediately, which can greatly reduce memory consumption.
+      this.canvas.width = 0;
+      this.canvas.height = 0;
+      delete this.canvas;
+    }
 
     this.loadingIconDiv = document.createElement('div');
     this.loadingIconDiv.className = 'loadingIcon';