I have non typical question. For example I have PC with 2 projectors connected to it. I use XRANDR to cat two displays (2 projectors) to one virtual screen.
So, as I understand I have two scan-out buffers for each projector. Each buffer contains RGB pixels, that will be outputted via Video Card.
I want to manipulate pixels before it will be scan out, but after xserver will render hole picture.
My question is How to do it? I think I must add a hook somewhere, but where? What level of software I must change? Somewhere in the kernel? Or I can change somewhere in xserver side?
All information will be usefull. Thanks!