Possible to intercept application paint and paint to framebuffer instead of desktop?

Possible to intercept application paint and paint to framebuffer instead
of desktop?

I am trying to paint a window offscreen into a framebuffer. So I can then
access this data (I.E: Save image of application even though it is non
existant onscreen. I want to launch notepad and have the machine intercept
the window before it paints and redirect it to a framebuffer(offscreen
surface). Does anyone know how this can be done?