Add `in color-space` syntax to gradients

[ai]

What would you want to propose?

Safari TP already got color space support for gradients:

background: linear-gradient(in lch, blue, red);

Suggested solution

This feature (but without in X syntax) was already implemented in postcss-easing-gradients by @larsenwork.

Maybe we can start from that code.

Additional context

This feature could be part of amazing colors refactoring going by @romainmenke.

Validations

• Follow our Code of Conduct
• Check that there isn't already an issue that request the same feature to avoid creating a duplicate.

Would you like to open a PR for this feature?

• I'm willing to open a PR

[romainmenke]

Notes :

• spec : https://drafts.csswg.org/css-images-4/#linear-gradients
• something about powerless components in polar spaces : https://twitter.com/svgeesus/status/1490827393031884808?s=20&t=vLd8y7izvSy8YcTOpYn5Zw

[romainmenke]

At @ai The pull request linked above will close this issue as fixed.
But that plugin on its own will be useless.

Hopefully I will have time for color-mix soon, then we can all have fancy new gradients.

[ai]

Looks amazing. Thanks.

I will promote it later, after some sort end of war. I can’t force myself to post any non-anti-war content 😓.