Vincent Povirk : windowscodecs: Ignore the alpha channel of ICO files if it 's empty.

[Alexandre Julliard]

Module: wine
Branch: master
Commit: d747652102d6e1e5662a0f49da7ffdbce3a3f460
URL:    http://source.winehq.org/git/wine.git/?a=commit;h=d747652102d6e1e5662a0f49da7ffdbce3a3f460

Author: Vincent Povirk <vincent at codeweavers.com>
Date:   Mon Jan 10 14:36:19 2011 -0600

windowscodecs: Ignore the alpha channel of ICO files if it's empty.

---

 dlls/windowscodecs/icoformat.c |   24 ++++++++++++++++++++++++
 1 files changed, 24 insertions(+), 0 deletions(-)

diff --git a/dlls/windowscodecs/icoformat.c b/dlls/windowscodecs/icoformat.c
index e6a590f..1e939d7 100644
--- a/dlls/windowscodecs/icoformat.c
+++ b/dlls/windowscodecs/icoformat.c
@@ -277,6 +277,30 @@ static HRESULT ReadIcoDib(IStream *stream, IcoFrameDecode *result)
             IWICBitmapFrameDecode_Release(framedecode);
         }
 
+        if (SUCCEEDED(hr) && has_alpha)
+        {
+            /* If the alpha channel is fully transparent, we should ignore it. */
+            int nonzero_alpha = 0;
+            int i;
+
+            for (i=0; i<(result->height*result->width); i++)
+            {
+                if (result->bits[i*4+3] != 0)
+                {
+                    nonzero_alpha = 1;
+                    break;
+                }
+            }
+
+            if (!nonzero_alpha)
+            {
+                for (i=0; i<(result->height*result->width); i++)
+                    result->bits[i*4+3] = 0xff;
+
+                has_alpha = FALSE;
+            }
+        }
+
         if (SUCCEEDED(hr) && !has_alpha)
         {
             /* set alpha data based on the AND mask */