567556 - Firefox occasionally displays the bopomofo ‘horizontal dash’ character vertically (used in ruby)

Status: RESOLVED WONTFIX

(Core :: Internationalization, defect)

Description

[Oli Studholme]

User-Agent:       Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10_6_3; en-US) AppleWebKit/533.4 (KHTML, like Gecko) Chrome/5.0.375.38 Safari/533.4
Build Identifier: 3.6.3

I tried to add the character ㄧ (used in Chinese bopomofo or zhùyīn fúhào), but on some pages it’s rendered vertically. The character should look like an em-dash —, but sometimes looks like vertical bar | . I haven’t noticed any reason for the inconsistency

Note that your rendering has recently improved. The third image of these bopomofo examples was from Firefox a month ago:
http://html5doctor.com/ruby-rt-rp-element/#bopomofo
and the current rendering works successfully:
http://oli.jp/example/ruby/#bopomofo1

but some characters in that page and in this wikipedia sample:
http://en.wikipedia.org/wiki/Bopomofo#Origin_of_the_letters
are still vertical

Chrome has the same bug:
http://code.google.com/p/chromium/issues/detail?id=44817

Reproducible: Always

Steps to Reproduce:
1. add the character ㄧ
2. On some pages it’s rendered the same as |. I haven’t noticed any reason for the inconsistency

Actual Results:  
2. On some pages it’s rendered the same as |

Expected Results:  
The character should look like an em-dash —

http://code.google.com/p/chromium/issues/detail?id=44817

Comment 1

[Boris Zbarsky [:bzbarsky]]

I see this too, on Mac, but are you sure this isn't just the result of a broken font that comes installed on Macs?  Different pages could well have different fonts specified.

Can you point to a page that has the "right" rendering?

Comment 2

[Oli Studholme]

@Boris thanks for the check. in that Wikipedia quote it’s only the first character I’m referring to, which is apparently U3127. Please note that I don’t know Chinese, but I’m under the impression that this character should be horizontal when used in bopomofo. Feedback from a native Chinese reader would be appreciated!

http://commons.wikimedia.org/wiki/Category:Unicode_Bopomofo
http://commons.wikimedia.org/wiki/Category:%E3%84%A7
Worryingly, this page states “ This Bopomofo character looks different in different fonts. It may look like |, or like —.”
http://www.alanwood.net/unicode/bopomofo.html
http://www.unicode.org/charts/PDF/U3100.pdf
The PDF notes “3127 ㄧ BOPOMOFO LETTER I (the horizontal stroke form is considered a rendering variant)”

Notes from Unicode Standard Annex #27, on Unicode 3.1 (underline and strikeout in source that presumably represent insertions and deletions (!) indicated via <ins> and <del> here):
http://unicode.org/reports/tr27/tr27-4.html

10.5 Bopomofo (revision)
On page 278, modify the "Standard Mandarin Bopomofo" paragraph as follows:

The order of the Mandarin Bopomofo letters U+3105.. U+3129 is standard worldwide. The code offset of the first letter U+3105 BOPOMOFO LETTER B from a multiple of 16 is included to match the offset in the ISO-registered standard GB 2312. The character U+3127 BOPOMOFO LETTER I <ins>may be rendered as either a horizontal stroke or a vertical stroke</ins> <del>is usually written as a vertical stroke when Bopomofo text is set vertically</del>. <ins>Often the glyph is chosen to stand perpendicular to the text baseline (e.g. a horizontal stroke in vertically-set text), but other usage is also common</ins>. In the Unicode Standard, <del>this representation is considered to be a rendering variation; the variant is not assigned a separate character code</del>. <ins>the form shown in the charts is a horizontal stroke; the vertical stroke form is considered to be a rendering variant. The variant glyph is not assigned a separate character code.</ins>

Conclusion: different browsers and pages may be using different fonts, vertical rendering may be correct for ruby text when the base text is in {writing-mode:tb-rl}, I was told by a Taiwanese person that the vertical rendering is incorrect in this style bopomofo (horizontal base text), and I have no idea what I’m talking about :) Chinese/Taiwanese feedback plz?

Comment 3

[Xidorn Quan [:xidorn] UTC+10]

It seems to me this is the issue of STHeiti. Now with OS X 10.11+ we use PingFang by default, which doesn't have this issue. And with all OS X before, Heiti TC is used for zh-TW content, which does not have this issue, either. Mark WONTFIX for this as it is no longer an issue for later systems, and never an issue for majority users of bopomofo who use zh-TW in general.