Remove css.types.color.color-contrast

[jamesnw]

Summary

The color-contrast() CSS function is no longer part of CSS Color Module Level 6. It was renamed to contrast-color(), and the spec has changed since Safari and Chrome did their experimental implementations.

There's a few layers to this decision (renaming an experimental feature and changing the functionality), but my thought is that the cleanest would be to view color-contrast() and contrast-color() as separate types, meaning:

• Set color-contrast to standard_track: false
• Remove the color-contrast spec link (it links to the spec for constrast-color)
• Create contrast-color once there is implementation.

I'm open to other ideas as well.

[caugner]

and the spec has changed since Safari and Chrome did their experimental implementations

Can you elaborate on the spec changes? Is there a particular spec PR? If the changes are small, then I could imagine that it makes sense to track it as a partial implementation with an alternative name.

[jamesnw]

and the spec has changed since Safari and Chrome did their experimental implementations

Can you elaborate on the spec changes? Is there a particular spec PR? If the changes are small, then I could imagine that it makes sense to track it as a partial implementation with an alternative name.

Digging a bit deeper has made it less clear- apologies. Essentially, the current implementation with color-contrast is not to any current spec, and there are 2 future levels of contrast-color.

Spec changes

In Level 5, the function takes a single color and an optional keyword max.

In Level 6, the function takes a color, an optional list of candidate colors, an optional yet-to-be-determined keyword for foreground or background, and an optional contrast algorithm.

There is a resolution on this issue to include an MVP in Level 5, and then full functionality in Level 6. There is an issue to add Level 5 syntax to Level 6 syntax.

Current implementation

I incorrectly thought there was Chrome implementation. The Safari implementation uses a color-contrast([base] vs [list]) syntax that is not in either level.

Given this, what makes the most sense for this key?

[caugner]

I incorrectly thought there was Chrome implementation. The Safari implementation uses a color-contrast([base] vs [list]) syntax that is not in either level.

Given this, what makes the most sense for this key?

Based on this, it would make sense to me to remove the color-contrast BCD feature altogether, as the old standard for it was effectively not implemented by any browser.

Requesting a second opinion from @Elchi3.

[Elchi3]

I agree with @caugner let's remove it altogether since it is essentially "spec-fiction" and not real.

[jamesnw]

Sounds good to me. @caugner I've removed color-contrast on this branch.