From 80aba1b34575eca66f020467901f1030f1fe8300 Mon Sep 17 00:00:00 2001
From: Vicente Penades <megaz0ne23@hotmail.com>
Date: Sat, 29 Apr 2017 00:24:59 +0200
Subject: [PATCH] Added missing function

---
 src/ImageSharp/PixelFormats/PixelTransformModeExtensions.cs | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/ImageSharp/PixelFormats/PixelTransformModeExtensions.cs b/src/ImageSharp/PixelFormats/PixelTransformModeExtensions.cs
index 50cda63827..4ecddfded0 100644
--- a/src/ImageSharp/PixelFormats/PixelTransformModeExtensions.cs
+++ b/src/ImageSharp/PixelFormats/PixelTransformModeExtensions.cs
@@ -43,6 +43,7 @@ namespace ImageSharp
                 case PixelTransformMode.Normal: return PorterDuffFunctions<TBckPixel, TSrcPixel>.NormalBlendFunction;
                 case PixelTransformMode.Multiply: return PorterDuffFunctions<TBckPixel, TSrcPixel>.MultiplyFunction;
                 case PixelTransformMode.Add: return PorterDuffFunctions<TBckPixel, TSrcPixel>.AddFunction;
+                case PixelTransformMode.Substract: return PorterDuffFunctions<TBckPixel, TSrcPixel>.SubstractFunction;
                 case PixelTransformMode.Screen: return PorterDuffFunctions<TBckPixel, TSrcPixel>.ScreenFunction;
                 case PixelTransformMode.Darken: return PorterDuffFunctions<TBckPixel, TSrcPixel>.DarkenFunction;
                 case PixelTransformMode.Lighten: return PorterDuffFunctions<TBckPixel, TSrcPixel>.LightenFunction;