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

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).

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/)?


--
Shinyu Murakami (村上 真雄)
CEO & Founder, Vivliostyle Inc.
http://vivliostyle.com
murakami@vivliostyle.com

Received on Tuesday, 19 May 2015 02:21:44 UTC