From 81f41cb9c79a96cecb6c51429963279202163836 Mon Sep 17 00:00:00 2001
From: Marc Pujol <mpujol@iiia.csic.es>
Date: Sat, 29 Apr 2017 18:49:31 +0200
Subject: [PATCH] Allow passing a pixel diff function as option

---
 resemble.js | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/resemble.js b/resemble.js
index 31bdba3..3e8493d 100644
--- a/resemble.js
+++ b/resemble.js
@@ -690,6 +690,10 @@ URL: https://github.com/Huddle/Resemble.js
 			errorPixel = errorPixelTransform[options.errorType];
 		}
 
+		if(options.errorPixel && typeof options.errorPixel === "function") {
+			errorPixel = options.errorPixel;
+		}
+
 		pixelTransparency = isNaN(Number(options.transparency)) ? pixelTransparency : options.transparency;
 
 		if (options.largeImageThreshold !== undefined) {