[Openicc] xrandr output properties / icc profiles

[Graeme Gill]

Kai-Uwe Behrmann wrote:

> * a client is not required to know about XRandR, so a accordingly set 
>   profile might be invisible, which is clearly inacceptable

I'm not sure that is true. Any client trying to manage color across
multiple screens should be trying to use XRandR to figure out what
part of its application window(s) are on which screen. If there are bugs,
then they need to be fixed, and they won't be fixed if the feature is
never used.

> I'd rather invest on, how to continue in setting the profile on the root 
> window and give additional hints about the Xinerama and XRandR output 
> mapping. This would be a more relyable base for a specification.

It's easy enough to provide both. What's not clear is the mapping
between the screen identification, and the property. There don't
seem to be any guaranteed mappings between any of the different
ways of identifying a particular X11 screen - ie., you can't
actually be certain that the first screen listed by native X, is
the same as the first one listed by Xinerama, or the same as the
first one listed by XRandR (witness the issues that have recently
cropped up with regard to inactive screens). So if you don't know
how a client is going to access a particular screen, how can you
know what _ICC_PROFILE_X property corresponds to it ?

With XRandR V1.2 and output properties there is no such ambiguity.
The ICC profile clearly belongs to the output the property is accessed under.

Graeme Gill.