[Openicc] Suggested update to "ICC Profiles in X Specification 0.4"

[Richard Hughes]

On 18 November 2016 at 00:50, Graeme Gill <graeme at argyllcms.com> wrote:
> As for Wayland, I'm struggling to locate documentation of Wayland's color
> management support - if any. There certainly doesn't appear to be anything
> in the place I'd expect to find it - the Wayland client doco. or protocol
> specifications. Pointers welcome.

There have been a couple of proposals on the list for full screen
color management, but each of these has concentrated on having the ICC
profile blob and not getting the information from the system. Weston
(the reference compositor for Wayland) uses colord and then falls back
to the weston.ini config file if not found if I remember correctly.

> I'm guessing that if an appropriate Wayland protocol was added (as an extension ?),
> then it would be possible to implement it using colord for Gnome systems, and
> also fix XWayland so that existing X11 applications will work (i.e. emulate
> root window _ICC_PROFILE setting/getting, XRANDR property getting/setting,
> CRTC lookup table getting/setting etc).

The CRTC modification in Wayland is done in the compositor, e.g.
gnome-shell or weston. colord-using tools are already setting the
gamma ramp in the session using the appropriate abstraction, so on X11
the GnomeRR is setting the ouput gamma ramp directly, and on Wayland
it's telling the compositor what to set over DBus. The concept of
atoms doesn't really exist using a wayland compositor.

Richard.