Re: post processing drawing

[Iulian Iliescu <iliescu iulian gmail com>]

I need to implement Chroma key behaviour.
DirectFB offers SetSrcColorKey(), but unfortunately this doesn't work for my platform (a PNX8935 chipset).
I tried to solve the problem by obtaining the layer bits and altering by hand the alpha values for those pixels that i need to hide. Unfortunately this works until next draw operation.

Paul Davis wrote:

On Mon, 2009-02-02 at 04:05 -0800, Iulian wrote:
  

I need to alter the alpha blending value of a drawing.
In order for this to be visible on the screen i need to do it after all GDK
controls has finished drawing.
I studied expose-event, but this doesn't guarantee me that no one will alter
the drawing.
Is there another event that is called after all drawing has been done?
    

i believe you're thinking about this all wrong.

why don't you describe what you are actually trying to accomplish and
maybe someone can make some useful suggestions.