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

[Dmitry Timoshkov]

Alexandre Julliard <julliard at winehq.org> wrote:

> >> 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.
> >
> > In order to draw it with a transparency it's necessary to create a 32-bpp
> > DIB section, copy source bitmap bits, and use GdiAlphaBlend() with a DIB
> > section. Basically my patch does all of this.
> 
> Yes of course. My question was whether on Windows it's drawn transparent
> even for the DDB case. I guess the answer is yes since you have an app
> that does this, but a small test case wouldn't hurt.

I just added the code to my test app to draw a bitmap with BitBlt()
loaded with LoadBitmap() (instead of assigning it to the Static control),
and the result is drawn without transparency under Windows.

-- 
Dmitry.