From 274df71c0ad12628df89f9a8cf39c76c366072f1 Mon Sep 17 00:00:00 2001
From: thatcher <thatcher.christopher@gmail.com>
Date: Fri, 1 Mar 2013 08:42:06 -0500
Subject: [PATCH] refs #22 use Math.pow per houseofyin and memoize
implementation of getLevelScale per acdha
---
src/tilesource.js | 14 +++++++++++++-
1 file changed, 13 insertions(+), 1 deletion(-)
diff --git a/src/tilesource.js b/src/tilesource.js
index 142609cb..51b0f03f 100644
--- a/src/tilesource.js
+++ b/src/tilesource.js
@@ -141,7 +141,19 @@ $.TileSource.prototype = {
* @param {Number} level
*/
getLevelScale: function( level ) {
- return 1 / ( 1 << ( this.maxLevel - level ) );
+
+ // see https://github.com/openseadragon/openseadragon/issues/22
+ // we use the tilesources implementation of getLevelScale to generate
+ // a memoized re-implementation
+ var levelScaleCache = {},
+ i;
+ for( i = 0; i <= this.maxLevel; i++ ){
+ levelScaleCache[ i ] = 1 / Math.pow(2, this.maxLevel - i);
+ }
+ this.getLevelScale = function( _level ){
+ return levelScaleCache[ _level ];
+ };
+ return this.getLevelScale( level );
},
/**