Color completion non hex

[GauravB159]

Partial fix for #166197 in conjunction with (Add PR ID for CSS Extension here)

The current code cannot parse hwb color function, or native color strings and does not render the color preview in completion. I have added an extra condition that simply takes the fact that the extension determined it was a color and renders it directly. It works for hwb and native colors now as long as the CSS Extension PR is merged.

[aeschli]

It's risky to take the value provided by an extension and set it to CSS. It could be used to inject custom css into VS Code.
The clean way would be to add a color field to the proposal API.

[GauravB159]

@aeschli I figured so. I thought adding a separate type in CompletionItemKind might be a good way, something like NativeColor that is set when one of that list of colors is true, but that too would be set by the extension and would have the same problem as well.

What do you mean by adding a color field to the proposal API? I can look into it

Edit: Do you mean the extension should pass a hash color value always that it used to display the preview? So the extensions themselves are responsible for parsing their color string.

[aeschli]

What do you mean by adding a color field to the proposal API? I can look into it

This would be new API. I wanted to bring it up for discussion with @jrieken.

[GauravB159]

Ah interesting! Let me know if I can help in any way when that comes around then, I suppose.

[romainmenke]

I don't think it is ideal to assume it is a renderable color when something has completion kind Color.

With custom properties, calc, color-mix and relative color syntax it is easy to write something that is a color, but can not be used to generate a preview.

:root {
  --a: rgb(var(--red-channel) 0 127);
  --b: color-mix(var(--one), var(--two));
  --c: rgb(from var(--a) calc(r / 2) g b);
}

These are all color values and should/could have completion kind Color but these are not suitable to use as values for a preview.