[patches] Add a color management framework to weston

[Graeme Gill]

Bill Spitzak wrote:

> These gamma ramps are an attempt to simulate a color conversion from
> some color space (sRGB?) to the color space of the output device.

No, they are not. Gamma ramp setting generally accomplishes one or
more of:

1) Setting the brightness to a calibrated level.
2) Setting the white point to a target color temperature.
3) Setting the gray response to a particular curve and
    neutrality.

Although you might be able to accomplish 2) using ICC profiles,
it isn't supported very well (absolute colorimetric & V4 ICC profiles etc.),
and it's better for the users state of adaptation if the whole screen
has a common white point.

3) helps non-color managed application, as well as making the
display more easily and accurately color profile-able.

> So > does this mean that the default color space of the buffers a client
> renders is sRGB?

You can't do that with 1D ramps - you need at least a matrix as well.
For general colorspace emulation you need a 3D cLUT.

Graeme Gill.