[Openicc] XICC specification draft (Xinerama vs. composite).

[Kai-Uwe Behrmann]

Exporting the screen geometries to applications would allow them to use 
whatever conversion they like and could work more soon.

The stage to convert colours with plugable CMMs controlled by the 
composite manager and hide this stuff from applications will need a bit of 
preparation. This is in my opinion the way for the long run.

regards
Kai-Uwe Behrmann
                                + development for color management 
                                + imaging / panoramas
                                + email: ku.b at gmx.de
                                + http://www.behrmann.name




Am 27.06.05, 16:26 -0400 schrieb Jim Gettys:

> This is one possibility, one not yet (and probably a couple years) from
> fruition.
> 
> How practical it is (e.g. is the quality high enough) is a different
> question.  Which is why I brought up the topic...
> 
> 			- Jim
> 
> 
> On Mon, 2005-06-27 at 19:42 +0200, Kai-Uwe Behrmann wrote:
> > This implies the color conversion should go in the composite manager, is 
> > this correct? Or do you prefer an other color conversion layer on top of 
> > it?
> > 
> > regards
> > Kai-Uwe Behrmann
> >                                 + development for color management 
> >                                 + imaging / panoramas
> >                                 + email: ku.b at gmx.de
> >                                 + http://www.behrmann.name
> > 
> > 
> > Am 27.06.05, 12:15 -0400 schrieb Jim Gettys:
> > 
> > > 
> > > Xinerama as it currently exists has a number of shortcomings, but
> > > many/most people find it useful.
> > > 
> > > By its nature, however, it is hiding multiple monitors as though they
> > > are one: if they are not matched in characteristics, Xinerama present
> > > major headaches for people interested in serious color.  It may be that
> > > presuming if you are running xinerama that the monitors/flat panels are
> > > a matched set is probably "good enough" for people who want to do that.
> > > 
> > > Another approach to the current Xinerama is possible once the new
> > > composite extension deploys widely and our drivers work well for it
> > > (right now, only certain X drivers can run composite effectively).
> > > We've certainly been talking about the possibility of making xinerama
> > > obsolete someday given composite.
> > > 
> > > For those of you not familiar with composite, here's a thumbnail sketch
> > > of how it works:
> > > 	When composite is enabled, rendering no longer goes to the frame
> > > 	buffer(s); instead, the rendering occurs in offscreen pixmaps.
> > > 
> > > 	An external application, called the compositing manager, becomes
> > > 	responsible for composing the real image in the real frame 
> > > 	buffer. (it gets told which windows have what pixels updated), 
> > > 	and the compositing manager may add eye candy of various sorts.
> > > 
> > > One could then have the compositing manager attempt to do a conversion
> > > from, say, linear rgb to what the real frame buffer needs to drive the
> > > particular monitor with color correction.  This conversion might be
> > > different on different monitors that make up the unified "screen" seen
> > > by applications. The issue then is whether the resolution of the
> > > information in the pixels is sufficient; my intuition is it probably is
> > > "most of the time", but probably not for serious applications.
> > > 
> > > But I'm not a color expert: you folks tell me ;-).
> > > 			Regards,
> > > 				- Jim