Commit 549f90bea for imagemagick.org

commit 549f90bea862c0cc15bc288cf761608d17902553
Author: Cristy <urban-warrior@imagemagick.org>
Date:   Thu Jul 16 18:56:59 2026 -0400

    https://github.com/ImageMagick/ImageMagick/issues/8864

diff --git a/MagickCore/composite.c b/MagickCore/composite.c
index a3058c8f7..6ed7df921 100644
--- a/MagickCore/composite.c
+++ b/MagickCore/composite.c
@@ -3357,10 +3357,11 @@ MagickExport MagickBooleanType CompositeImage(Image *image,
           }
           case PlusCompositeOp:
           {
-            D=(Da > 0.0) ? Dca/Da : 0.0;
-            S=(Sa > 0.0) ? Sca/Sa : 0.0;
-            pixel=(double) QuantumRange*(RoundToUnity(Sa+Da-Sa*Da)*
-              RoundToUnity(S+D));
+            blend=Sa+Da;
+            if (blend > 0.0)
+              pixel=(double) QuantumRange*((Sca+Dca)/blend);
+            else
+              pixel=0.0;
             break;
           }
           case ReflectCompositeOp: