CSS Values 4: mix()

[CanadaHonk]

Request for Mozilla Position on an Emerging Web Specification

• Specification Title: CSS Values and Units Module Level 4
• Specification or proposal URL (if available): https://drafts.csswg.org/css-values-4/#interpolate
• Bugzilla URL (optional): https://bugzilla.mozilla.org/show_bug.cgi?id=1836589
• Mozillians who can provide input (optional): @emilio

Other information

No engines implement or ship this yet.

[CanadaHonk]

CC also @dholbert

[emilio]

I think generally looks good. The main concern is implementation (this needs to be supported at the declaration-value level, for all properties, which can be tricky).

[zcorpan]

Are there use cases that aren't covered by calc() and color-mix()?

How does this work for shorthands?

[emilio]

To clarify the shorthand question:

background: url(foo.png) transparent;
background-color: mix(10%; red; blue);

How should .cssText or style.background serialize, since mix() is invalid at other than a declaration level? Similarly, background: mix(...);, how does .style.backgroundColor serialize? That all needs spec text.

[polyzen]

Seems this can be closed: mozilla/wg-decisions#1316

mix() itself was abandoned, but may be implemented another way: w3c/csswg-drafts#9658