HDR support in Wayland/Weston

[Adam Jackson]

On Wed, 2019-02-27 at 13:47 -0700, Chris Murphy wrote:
> On Wed, Feb 27, 2019 at 5:27 AM Pekka Paalanen <ppaalanen at gmail.com> wrote:
> > there is a single, unambiguous answer on Wayland: the compositor owns
> > the pipeline. Therefore we won't have the kind of problems you describe
> > above.
> > 
> > These are the very reasons I am against adding any kind of protocol
> > extension that would allow a client to directly touch the pipeline or
> > to bypass the compositor.
> 
> Well you need a client to do display calibration which necessarily
> means altering the video LUT (to linear) in order to do the
> measurements from which a correction curve is computed, and then that
> client needs to install that curve into the video LUT. Now, colord
> clearly has such capability, as it's applying vcgt tags in ICC
> profiles now. If colord can do it, then what prevents other clients
> from doing it?

The wayland server is capable of knowing the process on the other end
of the socket, and only exposing the color management control protocol
to specifically blessed clients.

- ajax