Stabilizing wl_scaler protocol extension

Pekka Paalanen ppaalanen at
Tue Sep 16 04:51:07 PDT 2014

On Tue, 16 Sep 2014 13:26:12 +0200
Alexander Preisinger <alexander.preisinger at> wrote:

> Hi pq,
> I use it in my wayland-next branch (for unstable wayland stuff) of the mpv
> player:
> In this commit:

Good to know, thanks.

> I only just now realized that I should just use set_destination for my use
> case.
> So setting the destination separately is definitely a use case and I think
> the set request is redundant.

True, but I'm worried how many upset people there will be if I break
the protocol during the migration by removing or renaming something. :-)
There should be no-one as it's all experimental still, but...

> So far I really like the scaler extensions. But the scaling quality has
> lots of room for improvement.
> I thought about improving the scaling quality, but didn't had the
> opportunity to look into it.

You mean in the Weston implementation? Yeah, that could very well be. I
think fixing that would come after
as it should make detecting the overall scaling factor a lot easier.

However, I'm more interested in the protocol aspect right now, and
there the scaling quality cannot be specified IMHO. We have to leave
room for hardware overlays doing the scaling in unknown ways.


> 2014-09-16 11:09 GMT+02:00 Pekka Paalanen <ppaalanen at>:
> > Hi,
> >
> > wl_scaler has been sitting in Weston for quite some time now:
> >
> >
> > I would like to collect comments and opinions on the protocol extension:
> > - Is it ready?
> > - Are the interfaces ok? As in, have a wl_viewport created for a
> >   wl_surface, instead of having wl_surface argument on a global request.
> > - Are the names ok?
> > - Should wl_viewport.set be removed as completely redundant?
> > - Do we care about maintaining compatibility with the current wl_scaler
> >   protocol, when moving it into Wayland?
> >
> > Obviously, if we change anything, it won't be compatible with the
> > current version.
> >
> > My goal is to move wl_scaler or equivalent into the Wayland repository.
> > That effort is now tracked at:
> >

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