[Openicc] ICC Profiles in X Specification 0.4

[Richard Hughes]

On 25 March 2010 10:09, Kai-Uwe Behrmann <ku.b at gmx.de> wrote:
> * multi monitor support and its relation to Xinerama/XRandR
> * server side colour management

What is the benefit of this to applications?

> * colour space tagging of window regions

Again, what's the high level usecase? Two use cases for me are, for example:

* Inkscape color corrects the active work area only using lcms to
convert an embedded image with a profile to the display profile
without a compositing window manager on low performance hardware
* A compositing frontend color corrects un-color-corrected areas in a
screen area on a high performance desktop on a high gamut LCD screen

A use case is the high level "what you want to do" rather than the
"how I'm doing it".

>> In this way it would be a bit like a firewall, where you only 'punch'
>> out regions of the desktop which are already color managed. All we
>
> Yes, thats what the compiz colour server plugin only does.

So why bother uploading profiles to the xserver? It looks to me all
the source profiles are being uploaded. What atom name are you using
to tag windows that already have done early color-correction? It seems
version 0.4 of the specification should just introduce this atom name
and _suggest_ that applications that are using _ICC_PROFILE use this
atom on each window they are color correcting themselves. Certainly
leave _ICC_DEVICE_PROFILE out of 0.4 until at least one other person
agrees it's a good idea.

> I would consider the ICC profile tagged regions a good thing to speed up a
> preview or to work in the 8-bit domain like firefox to offload the
> computation to the GPU. Its not that important to start with.

Then nuke it from the spec. If there's no agreed reason to do
something as complicated as uploading profiles for regions, then why
bother?

Richard.