[csswg-drafts] [css-color-5] What exactly is the behavior of the % adjuster in color-adjust()? (#6181)

tabatkins has just created a new issue for https://github.com/w3c/csswg-drafts:

== [css-color-5] What exactly is the behavior of the % adjuster in color-adjust()? ==
All of the adjusters in [`color-adjust()`](https://drafts.csswg.org/css-color-5/#coloradjust) are defined to take a `<percentage>`. There's no spec text defining what that % actually *does*, however.

The sole *example* appears to indicate that the % is directly added/subtracted from the value: `color-adjust(peru lightness -20%)` has its effect explained as "adjusted lightness is 62.2532% - 20% = 42.2532%", a straight subtraction of 20% (x - 20%), rather than a reduction *to* 20% (x * .2).

There's nothing *theoretically* wrong with this behavior, but it doesn't carry over to non-% channels, like "hue". This needs to be well-defined.

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(Or we can just drop color-adjust() and let the much more obvious (imo, at least) behavior of using calc() on channels from the relative color syntax handle all of this. See #6179.)

Please view or discuss this issue at https://github.com/w3c/csswg-drafts/issues/6181 using your GitHub account


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Received on Tuesday, 6 April 2021 14:47:00 UTC