[cairo] Re: [Mesa3d-dev] Points in Cairo Glitz paper

David Reveman c99drn at cs.umu.se
Thu Apr 22 09:38:43 PDT 2004

On Thu, 2004-04-22 at 08:41 -0700, Jon Smirl wrote:
> --- David Reveman <c99drn at cs.umu.se> wrote:
> > Offscreen rendering is important for cairo. Without offscreen rendering
> > cairo_surface_create_similar will not work and we can't do much else
> > than drawing trapezoids and composite surfaces efficiently. This is why
> > we haven't focused that much on supporting old hardware without pbuffer
> > support.
> But this is getting to my core point. Do we want offscreen rendering to be
> important to Cairo, or should we redesign Cairo to not need it? Anyway you slice
> it a system that requires pbuffers is going to be slower that one that doesn't.
> Should we step back and reconsider the API and see if the need for pbuffers can
> be eliminated? I'm sure that some of the people in the Mesa group can suggest
> ways to eliminate them and make things map better to existing 3D hardware
> without sacrificing drawing flexibility or quality.

Maybe I was I bit off when I said that without
cairo_surface_create_similar we can't do much. We've actually taken a
big step in the direction that you're describe with the introduction of
the new pattern interface to cairo. The OpenGL backend now much more
rarely need to use offscreen surfaces. e.g. solid stroking and filling
was done using offscreen surfaces earlier but that's no longer
necessary. Same thing with gradients, before we had the pattern
interface the only way to do gradients, was to scale an offscreen

- David

David Reveman <c99drn at cs.umu.se>

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