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 875d2a9cde9bccd8ec442dd93f2b79dbe254483c..307147447a5086b749c295524c20f7667bed8e96 100644 (file)
--- 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);