Re: [csswg-drafts] [css-color-4] Achromatic colors converted to hue-ish spaces should treat hue as "missing", not NaN (#6107)

> Most sample code [...]

I meant some CSS that would actually cause a conversion and expose its results directly to the author, not color conversion code in JS or whatever. The various Color 5 examples suffice, thanks. (Afaict I was right that *with Color 4 abilities only* a missing hue is never author-exposed, tho.)

Does this suggest that we can push the "author-exposed missing hue" value to Color 5? Or, since it *does* at least have effects that can be triggered by interpolation, maybe we do want to add it to the color functions' grammars here in Color 4?

If we do, I think we should add a missing saturation/chroma as well, right? d3 defaults to treating black/white as missing a chroma, which makes sense to me. And if we do that, should we allow a missing lightness to round out the set? No color meaningfully *starts* with a missing lightness (except maybe `transparent`), but the effects on interpolation are easy to define alongside the others; is there a use-case here?

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Received on Tuesday, 23 March 2021 18:38:58 UTC