Hi Andres.
I assume you mean DWOP_... and DWCAPS_ALPHACHANNEL.
DWCAPS_ALPHACHANNEL will add an alpha channel to the window back buffer
upon creation.
example: if the layer, where you will create the window on, has default
RGB16, then using DWCAPS_ALPHACHANNEL will make the window instead have
ARGB. If the layer is already default alpha capable, e.g. LUT, or
ARGB4444, then the window will be created with this format.
DWOP_ALPHACHANNEL will do the blitting operation with alpha blending.
Suppose you have a window with color 0,0,0,0 (black see-through) that
you blend onto a background with ff,ff,ff,ff (white opaque). If you do
NOT use DWOP_ALPHACHANNEL, the window will simply be copied resulting in
a "hole" in the background (the original background is gone, and black
instead if you have no layer behind). Using DWOP_ALPHACHANNEL will
result in no change, the white background is still visible.
o, and DWOP_ALPHACHANNEL is not possible without DWCAPS_ALPHACHANNEL.
You might need to "Flip" to see the effects.
Greets
Niels
Anders Bakken wrote:
What is the difference between the two of them? When do I use which?
Also, can I do the following:
Create a window without alpha, paint some opaque content.
At a later point use window->SetOptions(window, DWOP_ALPHACHANNEL).
Will the surface from GetSurface return a different surface then? Do I
need to release it and get it again?
Should I rather recreate the window?
regards
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