[cairo] Glitz surface?

Soeren Sandmann sandmann at daimi.au.dk
Tue Feb 24 05:14:01 PST 2009

Carl Worth <cworth at cworth.org> writes:

> [*] The 4x improvement might be almost entirely from avoiding the
> overhead of sending trapezoids to the X server, and then incrementally
> rasterizing them. An interesting experiment would be to change
> cairo-xlib to rasterize client-side and push the mask to the server
> before compositing, (which would also allow for doing spans-based
> rasterization of polygons). The original idea behind tessellation and
> trapezoid-rasterization was to take advantage of hardware-based
> trapezoid-rasterization, but since that isn't is sight now, (even after
> all this time), we should probably cut out all the unneeded
> overhead.

Another possibility is to add a 'polygon' Render picture and do the
polygon rasterization on the server. With a corresponding polygon
image type in pixman, cairo's image backend would also become faster
because compositing and rasterization could happen in one pass.

I don't know if there is a simple way of taking advantage of such a
polygon image with current graphics hardware though.


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