Support color operation functions in style

[nickidlugash]

Can we support color operation functions similar to the LESScss-type color functions supported in cartoCSS?

E.g.

lighten(constant, %)
darken(constant, %)
desaturate(constant, %)
spin(constant, %)
mix(constant1, constant2, %)
fadeout(constant, %)

If this is possible, does anyone have a sense as to how long it would take to implement? If it's not a quick thing then it's not high-priority for WWDC, but if it is quick then it could potentially save us a lot of time in the styling phase.

/CC @edenh @mourner @incanus @kkaefer

[kkaefer]

@mourner Is this implemented in GLJS?

[mourner]

@kkaefer Nope, not yet.

[incanus]

If it's not a quick thing then it's not high-priority for WWDC

I don't think this is quick. I don't think the math is hard, but parsing would take some work, especially on native.

[jfirebaugh]

⇢ mapbox/mapbox-gl-style-spec#38