From 0236be58cd37e9ee6b75e1da6d8c32c05067cb67 Mon Sep 17 00:00:00 2001
From: Cristy <mikayla-grace@urban-warrior.org>
Date: Fri, 15 Feb 2019 19:25:39 -0500
Subject: [PATCH] Respect read mask

---
 MagickCore/compare.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/MagickCore/compare.c b/MagickCore/compare.c
index 07cb31f34..f60a32722 100644
--- a/MagickCore/compare.c
+++ b/MagickCore/compare.c
@@ -430,6 +430,13 @@ static MagickBooleanType GetAbsoluteDistortion(const Image *image,
       register ssize_t
         i;
 
+      if ((GetPixelReadMask(image,p) <= (QuantumRange/2)) ||
+          (GetPixelReadMask(reconstruct_image,q) <= (QuantumRange/2)))
+        {
+          p+=GetPixelChannels(image);
+          q+=GetPixelChannels(reconstruct_image);
+          continue;
+        }
       difference=MagickFalse;
       distance=0.0;
       Sa=QuantumScale*GetPixelAlpha(image,p);
-- 
2.40.0