[PATCH 0/1] MR315: windowscodecs: Fix non-zero alpha detection in ImagingFactory_CreateBitmapFromHICON.

[Jinoh Kang (＠iamahuman)]

Increment pixel pointer for every *pixel*, not every *stride*.

Signed-off-by: Jinoh Kang <jinoh.kang.kr(a)gmail.com>

-- 
https://gitlab.winehq.org/wine/wine/-/merge_requests/315

[PATCH 1/1] windowscodecs: Fix non-zero alpha detection in ImagingFactory_CreateBitmapFromHICON.

[Jinoh Kang]

From: Jinoh Kang <jinoh.kang.kr(a)gmail.com>

Increment pixel pointer for every *pixel*, not every *stride*.

Signed-off-by: Jinoh Kang <jinoh.kang.kr(a)gmail.com>
---
 dlls/windowscodecs/imgfactory.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/dlls/windowscodecs/imgfactory.c b/dlls/windowscodecs/imgfactory.c
index c7e101e3d62..7a2107098c0 100644
--- a/dlls/windowscodecs/imgfactory.c
+++ b/dlls/windowscodecs/imgfactory.c
@@ -902,9 +902,9 @@ static HRESULT WINAPI ImagingFactory_CreateBitmapFromHICON(IWICImagingFactory2 *
         {
             /* If any pixel has a non-zero alpha, ignore hbmMask */
             bits = (DWORD *)buffer;
-            for (x = 0; x < width && !has_alpha; x++, bits++)
+            for (x = 0; x < width && !has_alpha; x++)
             {
-                for (y = 0; y < height; y++)
+                for (y = 0; y < height; y++, bits++)
                 {
                     if (*bits & 0xff000000)
                     {
-- 
GitLab

https://gitlab.winehq.org/wine/wine/-/merge_requests/315

[Esme Povirk (＠madewokherd)]

This didn't initially look right to me because the loop is written in a confusing way. We should always change x in the inner loop. I think it's probably correct but I'd like to see it cleaned up a bit more.

Since we don't actually care about the x and y coordinates, I would suggest a single loop over `width * height` pixels.

-- 
https://gitlab.winehq.org/wine/wine/-/merge_requests/315#note_2801