Convert between HSLuv and RGB.
HSLuv references: http://www.hsluv.org/
-- create a Color in the HSLuv color space
c = HSLuv.hsluv360 { hue = 150, saturation = 100, lightness = 50, alpha = 1 }
-- turn a color into normalized components
{ red, green, saturation, lightness } = HSLuv.rgb c0.19.0.18.