From dd87c2ef172f938d96ba66a353c6a88f3fbdedaf Mon Sep 17 00:00:00 2001
From: David Capello <davidcapello@gmail.com>
Date: Thu, 24 Sep 2015 23:50:44 -0300
Subject: [PATCH] Add minor check (bg index != local mask) to avoid checking
 the whole image

---
 src/app/file/gif_format.cpp | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/app/file/gif_format.cpp b/src/app/file/gif_format.cpp
index 19472ccf3..647f9a4b3 100644
--- a/src/app/file/gif_format.cpp
+++ b/src/app/file/gif_format.cpp
@@ -474,7 +474,8 @@ private:
     // Check if we need an extra color equal to the bg color in a
     // transparent frameImage.
     bool needsExtraBgColor = false;
-    if (!m_opaque && m_sprite->pixelFormat() == IMAGE_INDEXED) {
+    if (m_sprite->pixelFormat() == IMAGE_INDEXED &&
+        !m_opaque && m_bgIndex != m_localTransparentIndex) {
       for (const auto& i : LockImageBits<IndexedTraits>(frameImage)) {
         if (i == m_bgIndex &&
             i != m_localTransparentIndex) {