[cairo] DirectFB

Chris Wilson chris at chris-wilson.co.uk
Thu Apr 25 00:57:10 PDT 2013

On Wed, Apr 24, 2013 at 04:07:12PM -0600, Mike Steinert wrote:
>    I'm currently working on improving the DirectFB backend.
>    Is anybody else working on the DirectFB backend? I would prefer not to
>    duplicate work!
>    Would these changes be welcomed as a patch? If so, is it better to submit
>    a few smaller patches or submit everything once it's complete?
>    I currently have the surface acquisition code working with the software
>    renderer. I'm starting to look into the new(ish) compositor interface.
>    Initially I was looking at cairo-xlib-core-compositor.c for hints but now
>    I'm wondering if cairo-xlib-render-compositor.c (or perhaps something
>    else) would be a better starting point. Any hints here would be greatly
>    appreciated.

For the directfb backend, what you want to start with is management of
a shadow surface (which may just be a locked surface, it depends on
where those pixels are in memory - i.e. if they are uncached, then using
those directly would be disastrous for performance) and a damage
tracking interface. So basically just a fallback compositor.

cairo-xlib-render-compositor.c would only be an interesting comparison
if directfb gained a useful set of acceleration primitives. If it has,
then you would probably want to write a compositor to first try and use
the acceleration and then fallback to the damage tracked surface.

Chris Wilson, Intel Open Source Technology Centre

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