From: Cristy <urban-warrior@imagemagick.org>
Date: Sat, 25 Aug 2018 21:10:29 +0000 (-0400)
Subject: Don't composite alpha channel for -channel RGB
X-Git-Tag: 7.0.8-11~35
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=4c0c6a3c748ac30045d4844e04f61097b5ae3ec8;p=imagemagick

Don't composite alpha channel for -channel RGB
---

diff --git a/MagickCore/composite.c b/MagickCore/composite.c
index 037e40e15..4875e2455 100644
--- a/MagickCore/composite.c
+++ b/MagickCore/composite.c
@@ -1513,10 +1513,11 @@ MagickExport MagickBooleanType CompositeImage(Image *image,
 
         PixelChannel channel = GetPixelChannelChannel(image,i);
         PixelTrait traits = GetPixelChannelTraits(image,channel);
-        PixelTrait source_traits=GetPixelChannelTraits(source_image,channel);
+        PixelTrait source_traits = GetPixelChannelTraits(source_image,channel);
         if (traits == UndefinedPixelTrait)
           continue;
-        if (channel == AlphaPixelChannel)
+        if ((channel == AlphaPixelChannel) &&
+            ((GetPixelAlphaTraits(image) & UpdatePixelTrait) != 0))
           {
             /*
               Set alpha channel.