Re: [css-ruby] Overhanging and auto-hiding

On Tue, May 19, 2015 at 2:21 PM, Shinyu Murakami <murakami@vivliostyle.com>
wrote:

> fantasai <fantasai.lists@inkedblade.net> wrote on 2015-05-19 05:18:24
> > On 05/18/2015 07:24 AM, Xidorn Quan wrote:
> > > The current spec says:
> > >
> > >> The ruby annotations related to a ruby base must never overhang
> another ruby base.
> > >
> > > However, there are cases that a ruby base doesn't not actually have
> any annotation with it. One of the cases would be
> > > auto-hidden annotation. Also, if there is shortage of annotation, a
> ruby base could have no annotation to pair with.
> > >
> > > I propose that we should relax the restriction here, and allow ruby
> annotation to overhang ruby base if the ruby base doesn't
> > > have effective related annotation. Ruby base with no visible
> annotation should just be treated as plain text.
> >
> > I agree with this, but it would be good if Koji or Shinyu confirms
> > the expected behavior.
>
> I agree with Xidorn, too.
>
> BTW, I noticed the current spec does not define detailed overhang behavior
> and instead Example 12 says:
>
> > The user agent may use [JIS4051] recommendation of using one ruby text
> character length as the maximum overhang length. Detailed rules for how
> ruby text can overhang adjacent characters for Japanese are described by
> [JLREQ].
>
> So I checked JLREQ,
>
> JLREQ 3.3.8 Adjustments of Ruby with Length Longer than that of the Base
> Characters
>
> http://www.w3.org/TR/jlreq/#adjustments_of_ruby_with_length_longer_than_that_of_the_base_characters
>
> > a. Ruby text shall not hang over the ideographic characters (cl-19)
> adjacent to the base characters.
> > b. When the adjacent character is a hiragana (cl-15), katakana (cl-16),
> prolonged sound mark (cl-10) or small kana (cl-11), the ruby text may
> overhang the character up to the full-width size of the ruby characters.
> ...
> > (note 3) There is another variation that allows ruby text to overhang
> any ideographic characters (cl-19), hiragana (cl-15) or katakana (cl-16) up
> to the full-width size of a ruby character (see Fig. 3.83).
>
> I found a mistake in (note 3). The "full-width" here should be
> "half-width". The Japanese version says "最大でルビ文字サイズの二分までルビ文字を掛けてもよい" (up to
> the half-width size of a ruby character).
>

Yes, I also noticed this problem, and sent an email to public-i18n-cjk. [1]
They gave me the answer, but it seems that they haven't updated the
document accordingly.

I understand current WebKit and Blink's ruby overhang behavior is close to
> the note 3 (with s/full-width/half-width/). I think this is reasonable
> behavior for browsers that should avoid complex overhang rules. Is Gecko
> going to implement same way? and Example 12's description "recommendation
> of using one ruby text character length" should be changed (s/one/half/)?
>

I'm currently investigating how to implement, and what behavior should we
implement. I suppose that it wouldn't be much harder to implement the more
complicated behavior, so I'll probably implement that instead of that note
3 if that makes more sense.

[1]
https://lists.w3.org/Archives/Public/public-i18n-cjk/2015JanMar/0017.html

- Xidorn