From 764fa3e34aca8e8c69db05665987681a8495795d Mon Sep 17 00:00:00 2001
From: Henri Astre <henastre@microsoft.com>
Date: Tue, 17 Jun 2014 17:26:10 -0700
Subject: [PATCH] Fix memory leak while destroying the viewer.

---
 src/drawer.js               | 17 ++++++++-
 src/mousetracker.js         |  3 ++
 src/viewer.js               |  9 ++++-
 test/demo/memory_check.html | 71 +++++++++++++++++++++++++++++++++++++
 4 files changed, 98 insertions(+), 2 deletions(-)
 create mode 100644 test/demo/memory_check.html
diff --git a/src/drawer.js b/src/drawer.js
index 54b07281..95da18ce 100644
--- a/src/drawer.js
+++ b/src/drawer.js
@@ -302,7 +302,22 @@ $.Drawer.prototype = /** @lends OpenSeadragon.Drawer.prototype */{
      */
     canRotate: function() {
         return this.useCanvas;
-    }
+    },
+	
+	/**
+	 * Destroy the drawer (unload current loaded tiles)
+	 */
+	destroy: function() {
+		
+		//unload current loaded tiles (=empty TILE_CACHE)
+		for (var i=0; i<this.tilesLoaded.length; ++i) {
+			this.tilesLoaded[i].unload();
+		}
+		
+		//force unloading of current canvas (1x1 will be gc later, trick not necessary needed)
+		this.canvas.width  = 1;
+		this.canvas.height = 1;
+	}
 };
 
 /**
diff --git a/src/mousetracker.js b/src/mousetracker.js
index f92691c8..1017a4fa 100644
--- a/src/mousetracker.js
+++ b/src/mousetracker.js
@@ -252,6 +252,9 @@
         destroy: function () {
             stopTracking( this );
             this.element = null;
+			
+			THIS[ this.hash ] = null;
+			delete THIS[ this.hash ];
         },
 
         /**
diff --git a/src/viewer.js b/src/viewer.js
index aa4daa64..59b163b1 100644
--- a/src/viewer.js
+++ b/src/viewer.js
@@ -542,6 +542,10 @@ $.extend( $.Viewer.prototype, $.EventSource.prototype, $.ControlDock.prototype,
         this.drawersContainer.innerHTML = "";
         this.overlaysContainer.innerHTML = "";
 
+		if (this.drawer) {
+			this.drawer.destroy();
+		}
+		
         this.source     = null;
         this.drawer     = null;
         this.drawers    = [];
@@ -596,7 +600,10 @@ $.extend( $.Viewer.prototype, $.EventSource.prototype, $.ControlDock.prototype,
         if (this.outerTracker){
             this.outerTracker.destroy();
         }
-
+		
+		THIS[ this.hash ] = null;
+		delete THIS[ this.hash ];
+		
         // clear all our references to dom objects
         this.canvas = null;
         this.keyboardCommandArea = null;
diff --git a/test/demo/memory_check.html b/test/demo/memory_check.html
new file mode 100644
index 00000000..b2295d10
--- /dev/null
+++ b/test/demo/memory_check.html
@@ -0,0 +1,71 @@
+<!DOCTYPE html>
+<html>
+<head>
+    <title>OpenSeadragon Memory Check Demo</title>
+    <script type="text/javascript" src='../../build/openseadragon/openseadragon.js'></script>
+    <style type="text/css">
+
+      .openseadragon1 {
+          width: 800px;
+          height: 600px;
+      }
+
+    </style>
+</head>
+<body>
+    <div>
+        Simple demo page to monitor OpenSeadragon Memory Usage.
+    </div>
+	<button onclick="createViewer()">Create</button>
+	<button onclick="destroyViewer()">Destroy</button>
+	
+    <div id="contentDiv" class="openseadragon1"></div>
+    <script type="text/javascript">
+
+		var _viewer;
+		
+		var generateUniqueHash = (function() {
+			var counter = 0;
+			return function() {		
+				return "seadragon_"+(counter++);
+			};
+		})();
+		
+		function createViewer() {
+			if (_viewer) {
+				destroyViewer();
+			}
+			
+			_viewer = OpenSeadragon({
+				element: document.getElementById("contentDiv"),
+				showNavigationControl: false,
+				springStiffness: 20,
+				animationTime : 1.5,
+				visibilityRatio: 1,
+				hash: "hello",
+				tileSources: {
+					Image: {
+						xmlns:    "http://schemas.microsoft.com/deepzoom/2008",
+						Url:      'http://cdn.photosynth.net/ps2/92fe5de9-dffa-4315-9095-082da8b90642/packet/undistorted/img0014/',
+						Format:   "jpg", 
+						Overlap:  1, 
+						TileSize: 510,
+						Size: {
+							Width:  4592,
+							Height: 3448
+						}
+					}
+				}
+			});
+		}
+		
+		function destroyViewer() {
+			if (_viewer) {
+				_viewer.destroy();
+			}
+			_viewer = null;
+		}
+
+    </script>
+</body>
+</html>
\ No newline at end of file
