Hi there!

I'm interested in using babl as a color space converter for a software of mine. I find the HCY (hue, chroma, luma) color space useful, so I decided to include it in babl in order to migrate my color conversion codebase to babl.

The extension is based on the work and code of Kuzma Shapran (https://code.google.com/archive/p/colour-space-viewer), and mimics the HSV/HSL extensions. I have made a test program as well, using values from the original implementation passed through babl's gamma-to-linear conversion routines.

I'd like to submit this extension, but don't know how. Should I send it as an attachment, or perhaps make a pull request from git?

A couple of points though.

The original implementation uses the Rec. 601 luma coefficients, and as I'm aware babl prefers the sRGB Y values for the D50 illuminant (rgb-constants.h). Should I use these instead of the original ones?

While reading the code for the HSV extension I noticed a little possible improvement. Instead of computing x with fabs and fmod, given that we have cases for each hue sector, it's possible to predict the result of these operations and avoid using those functions, which I suppose would be faster. Already tested with the included test. Sounds ok? How do I post the patch?

Cheers!

Sirius.

PS. It would be cool to have support in babl for all kinds of color spaces, thus becoming the standard for color conversions in C (as I find this niche quite barren...). Is this consistent with the project goals? So as to make more extensions ;) The list at https://github.com/scijs/color-space looks rather tasty!