- From: Aaron Krajeski via GitHub <sysbot+gh@w3.org>
- Date: Wed, 19 Jul 2023 18:29:50 +0000
- To: public-css-archive@w3.org
mysteryDate has just created a new issue for https://github.com/w3c/csswg-drafts: == [css-color-5] Clarification on scaling ranges of color keyword parameters for relative color == Some web platform tests assume that an alpha of 1, when passed to the lightness channel of `lab`/`lch`, should result in a lightness value of 100: https://github.com/web-platform-tests/wpt/blob/master/css/css-color/parsing/color-valid-relative-color.html#L420 It appears that the logic for this is that the [0, 1] range for alpha should be mapped onto the [0, 100] range for lightness. I see nothing in the spec stating this should be the case: https://csswg.sesse.net/css-color-5/#relative-colors https://csswg.sesse.net/css-color-5/#relative-Lab In fact, this text seems to imply that numbers are _not_ remapped/normalized: > Except as specified for individual color functions, (for example, HWB Whiteness and Blackness return [\<percentage\>](https://csswg.sesse.net/css-values-4/#percentage-value)), the [channel keywords](https://csswg.sesse.net/css-color-5/#channel-keyword) return a [\<number\>](https://csswg.sesse.net/css-values-4/#number-value); if they were originally specified as a \<percentage\> or an [\<angle\>](https://csswg.sesse.net/css-values-4/#angle-value), that \<percentage\> is resolved to a \<number\> and the \<angle\> is resolved to a \<number\> of degrees (which is the [canonical unit](https://csswg.sesse.net/css-values-4/#canonical-unit)) in the range [0, 360]. If color keywords inputs _were_ to be mapped to their ranges, many tests are missing from wpt, for example: - Passing `lightness` to other components. - Normalizing the `hue` angle. - 100% for `a` in `lab` maps to a raw value of 125, should `a` values then be normalized as if they are in the range [0, 125]? - The above problem also exists for `oklab`, but with the range [0, 0.4] - The interaction of math functions with any of the above. Given that the spec is not explicit about this behavior and it is non-trivial, am I correct in assuming the aforementioned tests are incorrect? https://github.com/web-platform-tests/wpt/issues/41113 Please view or discuss this issue at https://github.com/w3c/csswg-drafts/issues/9094 using your GitHub account -- Sent via github-notify-ml as configured in https://github.com/w3c/github-notify-ml-config
Received on Wednesday, 19 July 2023 18:29:52 UTC