Question: How to tune the lightness curve

[bewantbe]

From issue #27 I know that you define the lightness curve as a linear ramp, so my question is: is it possible to custom this curve and still maintain the whole color equally spaced?

What I want is to make a colormap that mimic the colors of the sunset sky. I find that the current tool (viscm edit) could not stay in blue long enough, so I'm thinking of make hue/saturation change slower during blue region (hence lightness change faster).

I have some basic knowledge about color space (sRGB, CIE XYZ/LAB), so if you could point me out where is the related code that make it equally spaced would also helpful (e.g. how you equally slice arc length?).

Thanks!

[bewantbe]

OK, found it, the Bézier curves is using arc length parameter....