Thanks! I put the informations I gathered at http://www.selapa.net/swatches/gradients/
Please check and correct ;-) Olivier Le 12/12/10 21:44, Jon Cruz a écrit : > On Dec 6, 2010, at 2:02 AM, Olivier BERTEN wrote: > >> Well... I guess my question wasn't clear ;-) >> >> What I'm looking for are the actual algorithms used for gradients >> rendering in the different existing rendering engines. In other words: >> how do I compute the color value of a point in a gradient. >> >> Some underlying questions are: >> How do you deal with middle point? isn't it just another color stop? > Depending on the mode for the segment (see GIMP blend modes > http://wiki.inkscape.org/wiki/index.php/Swatch_Book#Gradient ). > > You probably should think of it more as a control point for the interpolation > function. > > >> For the software dealing with different color models, how do you deal >> with "mixed" gradients? from a RGB color to a CMYK color, for instance? >> The "Color gradient" article on Wikipedia says "In digital imaging >> systems, colors are typically interpolated in an RGB color space, often >> using gamma compressed RGB color values, as opposed to linear." > It really depends on the software. Adobe often will use the color > mode/colorspace with the most fidelity. CMYK is a common fallback. > > And even SVG that interpolates in RGB does allow for explicit control of > interpolation in either sRGB or linear RGB. > > >> Who does >> gamma compression? How? > > >> I guess the best way to know that is to look at the code so here's for >> Gimp. If you can give me directions for other rendering engines, that >> would be great. I'd like to get an equivalent of the >> gimp_gradient_get_color_at for other softwares. >> >> http://git.gnome.org/browse/gimp/tree/app/core/gimpgradient.c > For other software, things are trickier. However there are specs out there > for postscript, PDF, etc. And people like those in #scribus in IRC are quite > familiar with them. > > > > _______________________________________________ CREATE mailing list CREATE@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/create
