Japanese full-width transforms don't work

[r12a]

Latin text and numbers embedded in Japanese text are typically proportionally-spaced, but in some cases it is best to display them as full-width characters, especially for acronyms in vertically set text. For example, if the text "国际化活动W3C万维网联盟" is displayed vertically, the 'W3C' should be full-width, upright characters rather than proportionally-spaced text running down the line.

It's useful to be able to achieve this via styling, similar to the case conversion transforms used for Latin text.

Specs:
CSS Text provides text-transform: full-width to transform text in this way.

Tests & results:
Simple test, standard syntax • proprietary syntax

More tests: a-z, A-Z, punctuation, katakana, punctuation, symbols

Gecko supports this. Blink and Webkit do not.

Browser bug reports:
Chromium • Webkit

Priority:
The priority was set to basic by the initial reporter. This is certainly a very useful thing to have to hand when working with vertical text, in particular.

[r12a]

The first comment in this issue contains text that will automatically appear in one or more gap-analysis documents as a subsection with the same title as this issue. Any edits made to that comment will be immediately available in the document. Proposals for changes or discussion of the content can be made in comments below this point.

Relevant gap analysis documents include:
Japanese • [Korean]

[xfq]

• Chromium issue: https://bugs.chromium.org/p/chromium/issues/detail?id=684968
• WebKit bug: https://bugs.webkit.org/show_bug.cgi?id=143153

[xfq]

@r12a The "More tests" links seem to be broken?

[xfq]

The "More tests" links seem to be broken?

Sorry, now I see that the URLs work in the Gap Analysis document, and just don't work in the GitHub issue.

[r12a]

Hmm. Links should work here as well as in the document, so i fixed the hrefs. However, i'm not sure why they point to tests in the gap-analysis directory, rather than to the normal set of tests. I'll look into that later.

[himorin]

Hmm. Links should work here as well as in the document, so i fixed the hrefs. However, i'm not sure why they point to tests in the gap-analysis directory, rather than to the normal set of tests. I'll look into that later.

I was actually wondered on that when JLReq was in preparation on tests for gap-analysis. At that point, these tests seemed to be added at the same commit (e2be660) as initial update of gap-analysis document from template, and also were made/added before initial creation of i18n-tests repository. So, we thought there was some historical reason that these test files were not moved into i18n-tests from jlreq gap-analysis (but not sure on why).