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 <rlk@xxxxxxxxxxxx> http://www.tiac.net/users/rlk/ Tall Clubs International -- http://www.tall.org/ or 1-888-IM-TALL-2 Member of the League for Programming Freedom -- mail lpf@xxxxxxxxxxxx Project lead for The Gimp Print -- http://gimp-print.sourceforge.net "Linux doesn't dictate how I work, I dictate how Linux works." --Eric Crampton
