todo: Review HTML form controls

[kidayasuo]

Review all HTML form controls (button, input, select, textarea, etc) and other relevant elements (e.g. can replacement elements know the direction?) to see if/how they should support vertical writing direction. It is great if we can draw a general guideline that can be applicable even if new elements are added.

…via a feedback from Taku Yamaguchi responding the jlreq-d JEPA presentation on 2022-10-24. He provided sample pages as below:
https://cc-study.appspot.com/x04/vertical
https://cc-study.appspot.com/x04/horizontal

[kidayasuo]

w3c/jlreq#342 is related.

[r12a]

Also related:
w3c/jlreq#167 (gap analysis report)
and more at https://github.com/w3c/jlreq/issues?q=is%3Aissue+is%3Aopen+label%3Ai%3Avertical_text

Note that the gap analysis reports usually point to tests, which may be useful.

Of course, these issues are also relevant to Mongolian and Chinese.

[himorin]

forgot to mention during meeting,,, one another related discussion: openui/open-ui#522