On Mon, Aug 29, 2016 at 11:21:14PM -0400, John J Foerch wrote: > Hello, > > Has anybody used the color egg to do colorspace conversions? I'm > getting some unexpected results, and wonder whether there are bugs in > the egg, or whether I just misunderstand something about the colorspaces > involved. > > Here are the relevant links: > > http://wiki.call-cc.org/eggref/4/color > > http://people.csail.mit.edu/jaffer/slib/Color.html > > This call gives the result I expect: > > (color->sRGB (color:RGB709 1 0 0)) > => (255 0 0) > > This one does not: > > (color->e-sRGB 16 (color:RGB709 1 0 0)) > => (57216 24576 24576) > > I would expect a result of (65535 0 0) I just installed and used SLIB with Guile and got the exact result you did.
> This result also puzzles me: > > (color->L*C*h (color:RGB709 1 0 0)) > => (53.2405879437449 104.552006845446 39.997712561153) I got the exact same result under Guile on my PC. > I haven't worked with the L*C*h colorspace before, but from my reading, > since I gave pure red to convert, I would have expected a hue angle of > 0, a chroma of 100% and a luminosity of something like 50%. I agree with you that a hue angle of 39.9˚ is unexpected, given that you began with a pure red color. Have you noticed any other discrepancies with any of the other color spaces? I only have experience between L*C*h and sRGB. > Unfortunately the egg has no unit tests, and I think that if some could > be written, that would be very helpful. > > Is there anybody familiar with the color egg who can show me where > either it or I am going wrong? > > Thank you, > > -- > John Foerch -- Erik Falor Registered Linux User #445632 http://unnovative.net
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