Icon-theme-spec update for scaled icons

[Alexander Larsson]

> I assume this is for MacBook (pro) retina screens and Google's
> Chromebook?

For example. This kind of thing is just going to be more and more
common.

> Could you say something about the changes to wayland?

Well, you can look at the protocol changes if you want, but basically a
wayland compositor can decide to use a "scaling factor" for a particular
output, typically 2. The "size" of that output and windows on it will be
scaled by that. Soo, e.g. you could have (for easy math) a setup with
two outputs, one is 2000x2000 and the other one is 1000x1000. The
compositor pick scale=2 and reports the screens as 1000x1000 at 2x and
1000x1000 at 1x. A window of size 1000x1000 would exactly fill the screen
on both outputs, but would be scaled up on the first.

Additionally, apps can look at the output scale and supply a higher
resolution buffer for the window if it knows its displayed on that
output. In this case the window "size" would still be 1000x1000, but the
app says "window-scale is 2" and supplies a 2000x2000 surface when it
draws. In this case the compositor doesn't have to scale up (but may
gave to scale down on the lowres monitor).

> I am running Xquartz to run X11 apps on OS X and it looks pretty
> crappy now on a retina screen.
> I read on some X11 mailing list they wil not fix it.

Fixing X to do scaling is pretty hard, at the very least it will involve
X extensions and WM/Compositor support. I don't think apple is very
interested in this.

> If wayland does fix it, perhaps I can point the devs to the code and
> hope they can do anything with it.

It won't help them. X and Wayland are just too different in this case.