Composite and Shared Memory?

[Amir Bukhari]

it will be valuable if we could replace the off-screen Pixmap, which
Composite created when Window redirect, with one we create at client
side. this give us the ability to use Shared Memory Pixmap as
off-screen, so we didn't need to copy the redirected window pixmap to
our shared memory pixmap each time Damage occure.
is it that possible to do currently or it must be there new change in
Composite?

-- 
Amir Bukhari <ufz6 at rz.uni-karlsruhe.de>