From: Robin Watts <Robin.Watts@artifex.com>
Date: Wed, 2 Sep 2020 18:46:27 +0000 (+0100)
Subject: Bug 702527: Cope with nonseparable nonisolated blends of alpha only groups.
X-Git-Tag: ios-ice~3
X-Git-Url: https://git.ghostscript.com/?a=commitdiff_plain;h=be227e5dfd14c1f8050526aaa6c5b2c68e84c077;p=mupdf.git

Bug 702527: Cope with nonseparable nonisolated blends of alpha only groups.
---

diff --git a/source/fitz/draw-blend.c b/source/fitz/draw-blend.c
index 875d2a9cd..307147447 100644
--- a/source/fitz/draw-blend.c
+++ b/source/fitz/draw-blend.c
@@ -1114,6 +1114,9 @@ fz_blend_pixmap(fz_context *ctx, fz_pixmap * FZ_RESTRICT dst, fz_pixmap * FZ_RES
 	dp = dst->samples + (unsigned int)((y - dst->y) * dst->stride + (x - dst->x) * dst->n);
 	da = dst->alpha;
 
+	if (n == 1)
+		sa = da = 0;
+
 #ifdef PARANOID_PREMULTIPLY
 	if (sa)
 		verify_premultiply(ctx, src);