[css-values-4] Small/large/dynamic/logical viewport units

[andruud]

Request for Mozilla Position on an Emerging Web Specification

• Specification Title: CSS Values and Units Module Level 4
• Specification or proposal URL: https://drafts.csswg.org/css-values-4/#viewport-relative-lengths
• Caniuse.com URL (optional): https://caniuse.com/viewport-unit-variants
• Bugzilla URL (optional): https://bugzilla.mozilla.org/show_bug.cgi?id=1610815
• Mozillians who can provide input (optional): @emilio

Other information

• https://bugzilla.mozilla.org/show_bug.cgi?id=1287034 (some concerns about impl. details regarding logical variants).
• https://github.com/w3c/csswg-drafts/issues/6873 (related to some of the above concerns)
• WebKit has implemented this. https://bugs.webkit.org/show_bug.cgi?id=219287 https://bugs.webkit.org/show_bug.cgi?id=232895

[emilio]

The logical viewport units seem totally fair, with the concerns in https://github.com/w3c/csswg-drafts/issues/6873 addressed (I agree using element's computed writing-mode and not caring about propagation seems the most reasonable).

The small / large / dynamic units seem also relatively straight-forward and good for finally getting interop in mobile devices. @hiikezoe may have thoughts on that? But barring any objections from Hiro, I'd say either "worth prototyping", or event "important" for the mobile viewport ones seem reasonable positions.

[hiikezoe]

I will be totally supportive of the {small, large,dynamive} viewport units, and we actually are planning to implement them in 2022.