[RFC] wl_surface scale and crop protocol extension

[Pekka Paalanen]

On Tue, 30 Apr 2013 17:08:49 -0400
Matthias Clasen <matthias.clasen at gmail.com> wrote:

> On Tue, Apr 30, 2013 at 8:33 AM, Pekka Paalanen <ppaalanen at gmail.com>
> wrote:
> > Hi all,
> >
> > below is my first draft for a wl_surface scaling and cropping
> > extension. I called it wl_scaler in the lack of a better name. It is
> > designed similarly to the other wl_surface extensions
> > wl_shell_surface and wl_subsurface.
> >
> > There probably isn't any interesting details to debate, right? ;-)
> >
> > I'd like to have a better name for it, and you might want the set
> > request split into two or three, or not, but otherwise I'm quite
> > satisfied with it. I tried to take into account all existing
> > protocol that interacts with this.
> >
> > Comments? Is the language clear?
> 
> Can you describe some use cases where you envision using this ? Thats
> always a good starting point for discussing an api. The only other
> comment I have is that when you talk about scaling, you really need to
> say something about the interpolation method.

Oh right. The primary use case is for hardware video overlays, again. A
particular use case is for video to be (hardware assisted) decoded in
its native resolution, sent to a Wayland server, and scaled to fill a
window (a sub-surface, actually), again hardware assisted. So it is
mostly about the hardware accelerated zero-copy video presentation path.

I do not really know about interpolation methods. Defining one would
probably leave lots of hardware non-conformant, and I'd rather not do
that.


Thanks,
pq