[Mono-dev] Bitmap manipulation - am I doing it right?
stapostol at gmail.com
Wed Apr 1 04:37:25 EDT 2009
Την Wed, 01 Apr 2009 09:08:02 +0300,ο(η) Stifu <stifu at free.fr> έγραψε:
> How would that layer on top work, technically?
> Because if it's not part of the same Bitmap (the only painted on the
> and I that I need to paint twice, then there's some flickering happening.
> Hence the need for double buffering.
I cannot speak for GDI+, because I don't know its architecture. However it
does support alpha channels, which means it should be able to do alpha
blending. An easy test is to render a filled rectangle with A = 128, using
the Graphics object of the panel. (Hook the Paint event and make sure the
Bitmap is rendered before the Rectangle.)
If you are using double-buffering, the composition will always happen in
the backbuffer - hence no flickering.
Some general reading on alpha blending:
Code project article on alpha blending Bitmaps (which is not what you
actually want, but may be useful if the above technique does not work):
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