[csswg-drafts] [css-ui] Should we drop 'outline-color: invert' (#9199)

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

== [css-ui] Should we drop 'outline-color: invert' ==
The `outline-color` property has an `invert` value, which specified as being the initial value. More than a color as such, it calls for inversion of the color of the underlying pixels.

This value has been in the spec for the longest time, and was implemented in multiple browsers, but these browsers are pre-blink Opera, IE, and pre-blink Edge. No current browser supports it. As I understand it, this is generally considered too hard to do given how modern compositors work.

The spec does account for the fact that some browsers don't/won't support it:
>Conformant UAs may ignore the [invert](file:///Users/florian/src/csswg-drafts/css-ui-4/Overview.html#valdef-outline-color-invert) value on platforms that do not support color inversion of the pixels on the screen.
> 
> If the UA does not support the [invert](file:///Users/florian/src/csswg-drafts/css-ui-4/Overview.html#valdef-outline-color-invert) value, then it must reject that value at parse-time, and the initial value of the [outline-color](file:///Users/florian/src/csswg-drafts/css-ui-4/Overview.html#propdef-outline-color) property is the currentColor keyword.

We could keep it (a little complexified by the indirection via `auto` introduced by https://github.com/w3c/csswg-drafts/issues/7761). But is it worth it? If this is something we're moving away from, maybe it's time to drop it from the spec?

At the same time, the intent of that value does remain as relevant as it's always been: since outlines are important for accessibility, making sure they're always visible is desirable, and inverting the underlying color will achieve that in the overwhelming majority of scenarios.

So, is this a desirable hook for a useful behavior that someone some day may want to implement again, or is it an irrelevant leftover from times gone by?

Please view or discuss this issue at https://github.com/w3c/csswg-drafts/issues/9199 using your GitHub account


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Received on Wednesday, 16 August 2023 10:34:28 UTC