From 8d398864e337d6af1c6d30beaa22930c4e97be94 Mon Sep 17 00:00:00 2001
From: Alejandro Aguilera <fenixin@lavabit.com>
Date: Tue, 23 Aug 2011 21:37:10 +0200
Subject: [PATCH] Fix bad handle of both alpha layers being zero in composite.c

---
 overviewer_core/src/composite.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/overviewer_core/src/composite.c b/overviewer_core/src/composite.c
index 432ece8..d83701c 100644
--- a/overviewer_core/src/composite.c
+++ b/overviewer_core/src/composite.c
@@ -194,7 +194,7 @@ alpha_over_full(PyObject *dest, PyObject *src, PyObject *mask, float overall_alp
             }
             
             /* special cases */
-            if (in_alpha == 255 || *outmask == 0) {
+            if (in_alpha == 255 || (*outmask == 0 && in_alpha > 0)) {
                 *outmask = in_alpha;
 
                 *out = *in;