alpha-blending in a drawing area

[Andreas Volz <andreas brachttal net>]

Hello,

I search an ability to do some alpha-blending operations in a
gtk2-drawing area. I found gtkglext, but it has still problems with my
nvidia-card. Is there another ability to do alpha-blending without
opengl? 

I read something about the xrender-extension of X. Can I use this in a
gtk2-app? Some other ideas for alpha-blending?

Thanks
Andreas