[PATCH] comctl32/toolbar: Correctly draw disabled toolbar button which contains 32 bpp bitmap with alpha channel.

[Ziqing Hui]

According to my tests, on v6 comctl32, here is the disabled toolbar button appearance in different situation:

* 32bpp with alpha channel: Grayscale (This is not supported before v6)
* 32bpp without alpha channel ("without alpha channel" means each pixel's alpha value is set to 0): Solid color
* not 32bpp (maybe 24bpp, 16bpp etc.): Solid color

This patch handle the first situation for wine.

Wine-Bug: https://bugs.winehq.org/show_bug.cgi?id=24784
Signed-off-by: Ziqing Hui <zhui(a)codeweavers.com>
---
 dlls/comctl32/toolbar.c | 37 ++++++++++++++++++++++++++++++++-----
 1 file changed, 32 insertions(+), 5 deletions(-)

[Nikolay Sivov]

I think it might be possible to replace some of the logic in toolbar 
with correct DrawIndirect() arguments, potentially fixing or extending 
Imagelist() implementation. For example, does it need to check 
'has_alpha' on every draw or could imagelist do that once, until bitmap 
is replaced.