color management spec

[Graeme Gill]

Mikhail Gusarov wrote:
> How do compositing and color management relate anyway? They are not, and
> entangling them like this looks like an unnatural (not to say pereverse)
> move.

The general trend in display graphics systems is away from the model
where applications service expose events, towards one where applications/toolkits
render an applications windows contents in an off-screen pixmap, and then
a compositing manager combines all the windows onto a desktop.

This facilitates a variety of special effects, such as transparency,
thumbnails, 3D transformation, animations etc., as well as removing from the
application any need to respond to window arrangement changes, moving between
or straddling monitors etc.

Given that for correct color management the final rendered RGB values
depend on the monitor they get displayed on, and that a compositing manager
is trying to hide this detail from the application, then it becomes
the compositing managers responsibility to do the final color transformation.
Also given that all the performance effort nowadays is focused on the 3D rendering
hardware, it's also reasonable to try and execute the color transformation
using the fastest possible path, which is the GL texture lookup hardware.

Graeme Gill.