[PATCH] winex11: Copy icon color table in 256-color mode (Valgrind)

[Alex Henrie]

create_icon_pixmaps calls GetDIBits and create_pixmap_from_image, which
calls get_dib_info_size. GetDIBits sets biClrUsed to 0, which is a
special value meaning that the size of the color table is the maximum
size possible given the bit depth. Without code to handle that case in
get_dib_info_size, the color table is lost.

gdi32's version of get_dib_info_size does not have to deal with
biClrUsed being zero because bitmapinfo_from_user_bitmapinfo makes a
copy of the bitmap info with biClrUsed set to a nonzero value. However,
there is no reason to have anything that complicated in winex11.

Signed-off-by: Alex Henrie <alexhenrie24 at gmail.com>
---
Supersedes patch 171325
---
 dlls/winex11.drv/bitblt.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/dlls/winex11.drv/bitblt.c b/dlls/winex11.drv/bitblt.c
index 4eec3288e2..973af40c33 100644
--- a/dlls/winex11.drv/bitblt.c
+++ b/dlls/winex11.drv/bitblt.c
@@ -924,13 +924,14 @@ static void free_ximage_bits( struct gdi_image_bits *bits )
     XFree( bits->ptr );
 }
 
-/* only for use on sanitized BITMAPINFO structures */
 static inline int get_dib_info_size( const BITMAPINFO *info, UINT coloruse )
 {
     if (info->bmiHeader.biCompression == BI_BITFIELDS)
         return sizeof(BITMAPINFOHEADER) + 3 * sizeof(DWORD);
     if (coloruse == DIB_PAL_COLORS)
         return sizeof(BITMAPINFOHEADER) + info->bmiHeader.biClrUsed * sizeof(WORD);
+    if (!info->bmiHeader.biClrUsed && info->bmiHeader.biBitCount <= 8)
+        return FIELD_OFFSET( BITMAPINFO, bmiColors[1 << info->bmiHeader.biBitCount] );
     return FIELD_OFFSET( BITMAPINFO, bmiColors[info->bmiHeader.biClrUsed] );
 }
 
-- 
2.23.0