There's a certain kind of correction that we're using in gimp-print
that I'd like to be able to create a GUI element for.

In order to get more accurate colors, I've come up with with a color
correction technique in HSL space based on hue mapping and luminosity
mapping.  It's based on the following two transforms:

Ho = F(Hi)     F is a map (currently 48 points, with linear interpolation)

Lo = pow(Li, S * G(Ho)) G is another map

(no quibbles about RGB vs. CMY space for now, please)

That is, first the output hue is computed from the input hue, and then
the gamma is adjusted based on the hue, scaled by the saturation.
Somewhat to my surprise, it actually does a halfway decent job.

I'm not entirely sure what this GUI element would look like.  It has
something in common with a curves adjustment, but it would be useful
to display the result somehow.

Currently the F and G maps are embedded in the code, but clearly they
need to be adjustable somehow.  Having a useful way for people to
fiddle with them would be particularly handy.

There also need to be standalone utilities that can generate the
necessary maps for the Ghostscript and CUPS drivers, as well as for
the print plugin.  Hopefully a well-designed widget could be used for
all three applications.

Robert Krawitz <[EMAIL PROTECTED]>

Tall Clubs International  -- or 1-888-IM-TALL-2
Member of the League for Programming Freedom -- mail [EMAIL PROTECTED]
Project lead for The Gimp Print --

"Linux doesn't dictate how I work, I dictate how Linux works."
--Eric Crampton

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