[cairo] glitz_drawable_swap_buffer_region slow?

[stefan kersten]

On Wed, Mar 01, 2006 at 06:00:27PM +0100, David Reveman wrote:
> Swapping part of a drawable is implemented using glCopyPixels from back
> to front buffer and depending on the driver you're using this may or may
> not be accelerated. When swapping the complete drawable a call to [glX|
> agl...]SwapBuffers is made and that's always accelerated, it might even
> be implemented as a buffer flip and is then basically free.

ok, thanks david. so how would i go about implementing
partial updates efficiently? is there a way to find out
wether glCopyPixels is accelerated or not? would it be
better to draw each component into an offscreen surface and
composite the results? how can i find out if cairo+glitz
offscreen rendering is accelerated?

sorry if the answers those questions are obvious ...

<sk>