Andrew Coppin wrote: > I just uploaded a new version of the AC-Colour package...
Thanks for this. Your algorithm for scaling brightness is not correct however. The RGB values in all popular image formats are not linear. They use a gamma transfer function. So your algorithm will indeed change the colors in an image, not just its brightness. In some cases the change in color can be quite drastic. For a long-winded explanation and many examples, see: http://www.4p8.com/eric.brasseur/gamma.html You may want to implement one of the popular gamma transfer functions, such as BT.709 or sRGB. The former may also be useful for your AC-PPM package, since the PPM image format uses it, as specified in its documentation: http://netpbm.sourceforge.net/doc/ppm.html sRGB is used in most other popular image formats on the web nowadays. > Colour maps. Give it some control points, and it'll > (linearly) interpolate between them Your algorithm for this is actually not linear at all, since RGB values are generally not linear, as above. Regards, Yitz _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
