On 10/05/2010 01:20 AM, David Gowers (kampu) wrote: > In that case it really is a bug. Neither the input colors or output > colors contain 255. > > The output color series is: > 008700 008d00 009300 009800 009d00 00a200 00a700 00ab00 00af00 00b300 00b600 ... > But the outputs contain 0's. And that's not because they happened to come out to exactly 0, but actually they should be <0 and thus are clipped. So if expected clipping occurs, it's either to 0 or to 255. If no component of the output is 0 or 255 then it wasn't clipped. That said, the current algorithm has a limited precision. About 1.3% of possible RGB values will be off by one after a RGB-Lab-RGB conversion, 0.003% will be off by two (bright cyans are worst). LCH conversion is slightly worse. So far I haven't found a way to get perfect round-trips without being much slower. I currently have a floating point version which is at least 4 times slower. It gives perfect Lab roundtrips, and almost-perfect for LCH (off by one for 0.00006% of RGB values). It still needs quite a bit of work, but I am hoping to turn that into a viable babl candidate. Regards Rupert _______________________________________________ Gimp-developer mailing list Gimp-developer@xxxxxxxxxxxxxxxxxxxxxx https://lists.XCF.Berkeley.EDU/mailman/listinfo/gimp-developer
