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

[Graeme Gill]

Richard Hughes wrote:

Hi,

> 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.

yes, that is the impression I got. But I also get the impression that
Wayland isn't even matching XRANDR in basic capabilities such as
managing output configurations, so naturally there is no facility
to set or get ICC profiles.

> The CRTC modification in Wayland is done in the compositor, e.g.
> gnome-shell or weston.

Seem like a big hole in Wayland then, since that implies some
other non-standard protocol outside Wayland for applications to
manage this information.

> 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.

Which is fine for Gnome systems, but (AFAIKT) means that it's currently
impossible to write a cross-system Wayland application that manages color.

(i.e. it seems we are in the horrible situation that a Color
management applications needs to written to handle N x *nix
Application/UI operating environments, rather than simply
being able to use X11 or Wayland for all of them.)

Graeme.