[csswg-drafts] [css-color] color-contrast() default algorithm (#7361)

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

== [css-color] color-contrast() default algorithm ==
In https://github.com/w3c/csswg-drafts/issues/7356 and https://github.com/w3c/csswg-drafts/issues/7357 we're discussing adding syntax to specify specific contrast algorithm(s) to use. That leaves open the question of what algorithm is used if no contrast algorithm is specified. Options going forward:

- A) Use the UA's “best available” algorithm, which can change over time.
- B) Default to WCAG2.
- C) No defaulting: the algorithm must always be explicitly specified.
- D) Plan to default to whatever WCAG3 requires; in the meantime require it to be explicit.

As noted in multiple issues, WCAG2 has problems. It can return poorly contrasting colors in many cases, particularly in dark mode, and using it as the default entrenches the algorithm. The main benefits of using it are that it's already defined and very widely used, and allows us to return identical results in all UAs over time... at the expense of readability in the cases where it does poorly.

Defining color-contrast() to use the “best available” doesn't guarantee “interop” in the sense of always returning identical colors, but, it maximizes readability for users over time.

*(Issue filed following breakout discussions between @svgeesus, @fantasai, @argyleink and myself)*

Please view or discuss this issue at https://github.com/w3c/csswg-drafts/issues/7361 using your GitHub account


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Received on Tuesday, 14 June 2022 18:50:58 UTC