From 2d11034368845ebcf28d7ac13b1d3233bd93c5f1 Mon Sep 17 00:00:00 2001
From: Martin Laine <martin.laine@simplybusiness.co.uk>
Date: Tue, 15 Jul 2014 11:41:31 +0100
Subject: [PATCH] Add largeImageThreshold option to control when to skip pixels

---
 README.md   |  9 +++++++--
 resemble.js | 10 +++++++---
 2 files changed, 14 insertions(+), 5 deletions(-)

diff --git a/README.md b/README.md
index 62e1041..a40312f 100644
--- a/README.md
+++ b/README.md
@@ -63,11 +63,16 @@ resemble.outputSettings({
     blue: 255
   },
   errorType: 'movement',
-  transparency: 0.3
+  transparency: 0.3,
+  largeImageThreshold: 1200
 });
 // resembleControl.repaint();
 ```
 
+By default, the comparison algorithm skips pixels when the image width or height is larger than 1200 pixels. This is there to mitigate performance issues.
+
+You can switch this modify this behaviour by setting the `largeImageThreshold` option to a different value. Set it to **0** to switch it off completely.
+
 --------------------------------------
 
-Created by [James Cryer](http://github.com/jamescryer) and the Huddle development team.
\ No newline at end of file
+Created by [James Cryer](http://github.com/jamescryer) and the Huddle development team.
diff --git a/resemble.js b/resemble.js
index a09934b..84bce19 100644
--- a/resemble.js
+++ b/resemble.js
@@ -33,9 +33,11 @@ URL: https://github.com/Huddle/Resemble.js
 			}
 		}
 	};
-	
+
 	var errorPixelTransformer = errorPixelTransform.flat;
 
+	var largeImageThreshold = 1200;
+
 	_this['resemble'] = function( fileData ){
 
 		var data = {};
@@ -347,7 +349,7 @@ URL: https://github.com/Huddle/Resemble.js
 
 			var skip;
 
-			if( (width > 1200 || height > 1200) && ignoreAntialiasing){
+			if(!!largeImageThreshold && ignoreAntialiasing && (width > largeImageThreshold || height > largeImageThreshold)){
 				skip = 6;
 			}
 
@@ -592,9 +594,11 @@ URL: https://github.com/Huddle/Resemble.js
 		if(options.errorType && errorPixelTransform[options.errorType] ){
 			errorPixelTransformer = errorPixelTransform[options.errorType];
 		}
-		
+
 		pixelTransparency = options.transparency || pixelTransparency;
 
+		largeImageThreshold = options.largeImageThreshold || largeImageThreshold;
+
 		return this;
 	};