[PATCH 2/2] comctl32: Paint 32-bpp bitmaps with an alpha channel using GdiAlphaBlend.

[Alexandre Julliard]

Dmitry Timoshkov <dmitry at baikal.ru> writes:

> Alexandre Julliard <julliard at winehq.org> wrote:
>
>> It's not clear that an alpha channel is even meaningful with a DDB, did
>> you test that case?
>
> The app loads the bitmap using LoadBitmap(), i.e. it gets loaded without
> creating a DIB section, then the app assigns it to "Static" control.
> Calling BitBlt() with that bitmap as a source and a 32-bpp DIB section
> as a destination works just fine under Windows and Wine, and the result
> preserves alpha. Is that what you mean with testing a DDB?

I don't particularly care about BitBlt() behavior, but I still think
GetDIBits() is preferable, particularly since it works even if the
bitmap is already selected in a DC.

My question was whether it's drawn with transparency in that case, since
it's not really specified in which cases a DDB is considered to have an
alpha channel.

-- 
Alexandre Julliard
julliard at winehq.org