Re: [csswg-drafts] [css-color-4] Do we actually need hwb()? (#6940)

> A triangle with black at the bottom, white at the top, and the most saturated/high chroma color of a given hue as the third corner is a natural representation of a constant-hue slice through a color gamut. Perceptual representations will have varying shaped triangles (and may have curved edges) while not-really-perceptual ones will go for a regular isosceles triangle.

Hm, my point is that the "rectangle" view is an accurate representation of the *coordinate space* - for a given hue, you can specify colors in the (high chroma, high lightness) and (high chroma, low lightness) corners. HSL actually treats these colors as meaningful, which is nonsense, of course, but it does make for a very simple way to represent the coordinates, and that's equally true for LCH (it just doesn't pretend those colors outside the triangle-ish area are real). The triangle only arises by specially marking the out-of-gamut colors; they're still possible to *specify*.

I suppose technically HWB's equal-hue slices are the same if you were to just map them to a square with W/B axises, but it feels like that's not a natural interpretation of the coordinates; for one, it puts the pure hue off in a corner. The triangle, representing weights of the three colors (or equivalently, with the altitude from the hue-corner representing w+b %, and then perpendicular distance representing w% vs b% balance), represents it well; it omits some values you can technically specify, but only redundant ones that can be specified in other ways.

>> LCH and HSL are identical in terms of ease of creation/manipulation
>
> Not really, and the spec already makes that very clear:

In the sense I am meaning, yes really - both of them model colors with the "saturation(chroma) + lightness" model; the entire point of HWB is the assertion that this isn't a very natural model to think in, and that "hue + white + black" is more natural.

I'm well aware of the differences between HSL and LCH and why LCH is a marked improvement, but those differences aren't relevant to what I was saying.

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Again, I know that HWB is a non-perceptual space; it's just a recasting of HSL, which is just a recasting of RGB. I'm not defending it on those grounds; that would be silly. I'm just pointing out that it *does* have reasons to exist, which aren't met by the other new color functions.

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Received on Friday, 14 January 2022 19:19:11 UTC