API - Color: Implement hex parsing

[bryphe]

We have a small Color API to parse / work with colors - it's very bare-bones at the moment, though!

One important feature we need for it is creating colors from hex-values. Some examples of cases we should be able to parse:

• #FFF (3 element, rgb)
• #FFFA (4 element, rgba)
• #01010F (6 element, rgb)
• #0101CC0F (8 element, rgb)

It'd be fine to use a library for this (I'm sure there is one existing), but the main thing is just that we can parse these hex colors and get the right output.

An API like Color.hex("#FFF") that returns a Color.t would be perfect. We should have tests covering this case, as well.

[bryphe]

This is a good place to start looking: https://github.com/bryphe/revery/blob/master/src/Core/Color.re

[bryphe]

Sounds like @kitten might help us out here! 💯

[rauanmayemir]

What do you think about factoring out Color to be universal to some extent?

There are https://opam.ocaml.org/packages/gg/ and https://opam.ocaml.org/packages/color/, and I've been considering to base some solution off of it for Brisk. Your implementation is as close as I'd imagine it myself.

[bryphe]

What do you think about factoring out Color to be universal to some extent?

Would be open to it, if it'd be useful!

There are https://opam.ocaml.org/packages/gg/ and https://opam.ocaml.org/packages/color/, and I've been considering to base some solution off of it for Brisk.

Cool. I didn't know about https://opam.ocaml.org/packages/color/ - that looks like exactly what we need for parsing / hex conversion. The only other thing we really have beyond that here is our list of colors contributed by @bgoscinski : https://github.com/bryphe/revery/blob/master/src/Core/Colors.re - is that something that would be useful for Brisk?

[rauanmayemir]

Sure, why not. I wonder if they could be upstreamed into Color or Gg, otherwise, we'd end up repeating it everywhere.

[kitten]

I'm not that experienced in dealing with Dune, so I'd be happy to leave this up to someone else if we'd like to go for https://github.com/anuragsoni/color :)

[bryphe]

I went ahead and added the @opam/color lib 👍 (And exposed just a thin wrapper that basically shifts the API from snake case to camel case).

@rauanmayemir - @jchavarri had an idea that is relevant to the sharing out of these sorts of APIs. He drafted a proposal here: revery-ui/reason-reactify#35

I think it's a really cool idea - having some set of basic primitives that could be used between projects. Wouldn't it be neat if you could create a custom component that could be used in both revery and brisk, for example? Would be great to get your feedback on that issue!