Internationalization Comments on CSS3 Ruby Module

Version reviewed

Lead reviewer

Richard Ishida


These are comments on behalf of the Internationalization Core WG, unless otherwise stated. The "Followup" column indicates who has been assigned the responsibility of tracking discussions on a given comment.

We recommend that responses to the comments in this table use a separate email for each point. This makes it far easier to track threads.


ID Location Subject Comment Followup Ed. /
Discussion threads
1 3.1 Box model link

There should be a link to the CSS3 Box Model module.

2 3.2 display: rp value

"Because the purpose of the XHTML rp element [RUBY] is to allow pre-existing user agents to parenthesize ruby text content, an XHTML user agent should use a styling rule for these elements that avoids rendering them such as rp {display: none}."

The rp element has to be correctly handled by XML markup also, not just XHTML, so there should be an rp value for display in section 3.1.

Whether the rp text is displayed or not is down to whether or not the user agent supports ruby - if it does, it should automatically hide rp elements by default.

3 3.3 List module link

There should be a reference to the CSS3 Line Module.

4 4.1 Vertical layout not enough for bopomofo

"In order to achieve that effect, vertical-ideographic layout should be set on each individual ruby. That can be accomplished with the following simple CSS rule: ruby.bopomofo { writing-mode: tb-rl }"

This is not sufficient. The accents in bopomofo ruby are not displayed as a unidirectional run of text. Bopomofo accents are non-combining characters that in memory follow the sequence of bopomofo alphabetic characters spelling out a syllable. However, the second to fourth tones are displayed in a separate vertical column to the right of the alphabetic characters, and the neutral tone marker is displayed as a dot above the column of alphabetic characters.

5 4.1 right Expected behaviour for value right

Please provide a more detailed explanation and examples of expected behaviour for the value right. This is currently not clear at all.

My understanding, from talking with Michel Suignard, is that this was intended to support the bopomofo case, which requires special placement of ruby text characters on the right side of horizontal and vertical text.

(If this is the case, it may be better to call this value 'bopomofo', since the rules for bopomofo tone placement are very idiosyncratic.)

6 4.1 Location of bopomofo ruby description

The description of bopomofo ruby currently in the spec belongs in the section describing the value right.

Note that bopomofo is usually rendered to the right of individual Han character glyphs, but can also occasionally be rendered before as per normal furigana in Japanese.

7 4.1 inline value description missing The description of the inline value is completely missing. (See section 5.) RI S
8 4.2 left/start and right/end

Left/start, and right/end are not equivalent in right to left scripts and should not be synonymous. For example, start is towards the beginning of the line, therefore right in RTL text. Left and right should be broken out as separate values with their own descriptions.

RI (raised by FY) S
9 4.4 example s/ruby-base/ruby/

On the first line: s/ruby-base/ruby/

10 Other Default stylesheet

The Ruby Annotation Rec says in section 3.4:

[A sample user agent default style sheet which describes this formatting will be provided by [CSS3-RUBY] or its successor document.]

Will this be provided?

This comment has not yet been approved by the i18n WG.

11 References New version of JIS 4051

"Line composition rules for Japanese documents (日本語文書の行組版方法) JIS X 4051-1995, Japanese Standards Association, 1995 (in Japanese)"

Please update the reference to the 2004 version of the JIS spec, which we believe to be the latest.


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