From: Cristy <urban-warrior@imagemagick.org>
Date: Sat, 13 Aug 2016 23:29:18 +0000 (-0400)
Subject: ://github.com/ImageMagick/ImageMagick/issues/250
X-Git-Tag: 7.0.2-8~1
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=74b1d5d41f68ff170031101a689bc9ca162c60b9;p=imagemagick

://github.com/ImageMagick/ImageMagick/issues/250
---

diff --git a/ChangeLog b/ChangeLog
index 2b06786d9..1586ae26c 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,6 +1,8 @@
 2016-08-07  7.0.2-8 Cristy  <quetzlzacatenango@image...>
   * Prevent spurious removal of MPC cache files (reference
     https://www.imagemagick.org/discourse-server/viewtopic.php?f=3&t=30256).
+  * Note alpha channel when combining 4 or more images (reference
+    https://github.com/ImageMagick/ImageMagick/issues/250).
 
 2016-08-06  7.0.2-7 Cristy  <quetzlzacatenango@image...>
   * Release ImageMagick version 7.0.2-7, GIT revision 10980:ecc03a2:20160806.
diff --git a/MagickCore/channel.c b/MagickCore/channel.c
index 1c64db9b3..38282e8d7 100644
--- a/MagickCore/channel.c
+++ b/MagickCore/channel.c
@@ -507,8 +507,30 @@ MagickExport Image *CombineImages(const Image *image,
     (void) SetImageColorspace(combine_image,sRGBColorspace,exception);
   else
     (void) SetImageColorspace(combine_image,colorspace,exception);
-  if ((GetPixelAlphaTraits(image) & UpdatePixelTrait) != 0)
-    combine_image->alpha_trait=BlendPixelTrait;
+  switch (combine_image->colorspace)
+  {
+    case UndefinedColorspace:
+    case sRGBColorspace:
+    { 
+      if (GetImageListLength(image) > 3)
+        combine_image->alpha_trait=BlendPixelTrait;
+      break;
+    }
+    case GRAYColorspace:
+    {
+      if (GetImageListLength(image) > 1)
+        combine_image->alpha_trait=BlendPixelTrait;
+      break;
+    }
+    case CMYKColorspace:
+    { 
+      if (GetImageListLength(image) > 4)
+        combine_image->alpha_trait=BlendPixelTrait;
+      break;
+    }
+    default:
+      break;
+  }
   /*
     Combine images.
   */