https://github.com/ImageMagick/ImageMagick/issues/1298

diff --git a/MagickCore/composite.c b/MagickCore/composite.c
index 56fba7345f636077903a26c9437c2205d6e545f0..1dd6bb8de4900c3d0671281b7b3a4c4bb7a8c8f4 100644 (file)
--- a/MagickCore/composite.c
+++ b/MagickCore/composite.c
@@ -1415,6 +1415,7 @@ MagickExport MagickBooleanType CompositeImage(Image *image,
         case ColorBurnCompositeOp:
         case ColorDodgeCompositeOp:
         case DarkenCompositeOp:
+        case DifferenceCompositeOp:
         case DivideDstCompositeOp:
         case DivideSrcCompositeOp:
         case ExclusionCompositeOp:
@@ -1466,7 +1467,6 @@ MagickExport MagickBooleanType CompositeImage(Image *image,
           alpha=Da*(1.0-Sa);
           break;
         }
-        case DifferenceCompositeOp:
         case OutCompositeOp:
         case SrcOutCompositeOp:
         {

diff --git a/MagickCore/morphology.c b/MagickCore/morphology.c
index 258432562a496e616c53eba7e7d17f5be96345e3..131396836d0dc272dd9ed4f0e7684554484b8414 100644 (file)
--- a/MagickCore/morphology.c
+++ b/MagickCore/morphology.c
@@ -3984,7 +3984,7 @@ MagickPrivate Image *MorphologyApply(const Image *image,
             (void) FormatLocaleFile(stderr,
               "\n%s: Difference of Dilate and Erode",CommandOptionToMnemonic(
               MagickMorphologyOptions, method) );
-          (void) CompositeImage(curr_image,save_image,DifferenceCompositeOp,
+          (void) CompositeImage(curr_image,save_image,OutCompositeOp,
             MagickTrue,0,0,exception);
           save_image = DestroyImage(save_image); /* finished with save image */
           break;