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Re: [css-ruby] Tone mark of bopomofo in ruby

From: Koji Ishii <kojiishi@gmail.com>
Date: Fri, 30 Jan 2015 02:47:41 +0900
Message-ID: <CAN9ydbV85z1YokeonmSi6Vopx-WYEo0icoTCmphmjhaw=GZa_Q@mail.gmail.com>
To: Xidorn Quan <quanxunzhen@gmail.com>
Cc: Bobby Tung <bobbytung@wanderer.tw>, www-style list <www-style@w3.org>, CJK discussion <public-i18n-cjk@w3.org>
After reading Richard's new blog post[1], especially its Questions
section[2], and with some conversation with him, I'm started to be
convinced that doing this in inter-character might make more sense.
Doing it in fonts still look good if it works, but if Richard's
analysis is right about it can't be done with existing features,
adding an OpenType feature for Bopomofo might be harder.

The first point Xidorn made is right, but if I understand right, the
vast majority of Bopomofo is for ruby, right? Start from ruby might
make more sense if so.

The second point is a spec issue. The forthcoming CLREQ could help,
editor resource maybe an issue but there could be contributors. I
think more important question is whether impl are interested in or
not.

I heard that CLREQ is going to be published sometime this spring. If
specs can be done somehow, will you be interested in?

[1] http://rishida.net/scripts/bopomofo/ontheweb.html
[2] http://rishida.net/scripts/bopomofo/ontheweb.html#questions

/koji

On Sat, Jan 24, 2015 at 9:50 PM, Xidorn Quan <quanxunzhen@gmail.com> wrote:
> I made a better version of the polyfill. You can check it in the attachment.
> It looks perfect on Trident, WebKit, and Blink. (Some problems with Gecko
> again, because of, I guess, incomplete impl of vertical text and ruby...)
>
> - Xidorn
>
> On Sat, Jan 24, 2015 at 7:03 PM, Koji Ishii <kojiishi@gmail.com> wrote:
>>
>> I had an impression that someone has solved somehow and Bobby knows
>> that, because WebKit has implemented inter-character already. It's a
>> bit unfortunate to know that this wasn't solved yet.
>>
>> I agree with Xidorn that this should be solved outside of the ruby spec.
>>
>> So, both of you know the spec/algorithm to layout Bopomofo tonemarks?
>> I suspect still-in-work CLREQ might cover that, but if there was a
>> polyfill on github, that'd be a great first step. It helps authors,
>> and it may help possible contributors with font knowledge to
>> understand the necessary spec/algorithm.
>>
>> /koji
>>
>> On Fri, Jan 16, 2015 at 10:11 AM, Bobby Tung <bobbytung@wanderer.tw>
>> wrote:
>> > Hi Xidorn,
>> >
>> > I remember this issue is discussed in TPAC 2014 ruby session. Layout
>> > Engine
>> > and fonts' GPOS are ok for the tone marks.
>> >
>> > But fonts vary and may take longer for penetration. I'd like to hear
>> > more
>> > comments from implement side for the issue.
>> >
>> > WANDERER Bobby Tung
>> > Sent from my iPhone.
>> >
>> > Xidorn Quan <quanxunzhen@gmail.com> 於 2015年1月16日 上午8:38 寫道:
>> >
>> > Hi,
>> >
>> > The current CSS Ruby spec requires UAs to position the tone marks in
>> > ruby
>> > annotation properly in the note below "ruby-position: inter-character;"
>> > [1]
>> > and I was trying to implement this during the last few days. But it then
>> > makes me wonder whether it is worth to implement this in layout engine.
>> >
>> > The first reason made me think about this was the fact told by Bobby
>> > that
>> > the tone marks are always positioned in a separate column for vertical
>> > bopomofo in all contexts, not only when they are inside ruby annotation.
>> > Which means, the tone mark positioning is not limited to inter-character
>> > ruby; it also covers ruby and non-ruby text in vertical text. It is
>> > definitely what fonts should handle.
>> >
>> > The other potential problem for this is that, it will never be
>> > interoperable
>> > until all UAs implement this in the same way. There are a lot of details
>> > need to be considered, for example, what tone marks should be
>> > repositioned?
>> > Only trailing ones, or every one? What exactly position the tone mark
>> > should
>> > be placed when font or font size vary? It would be hard for author to
>> > detect
>> > whether a UA support the tone mark positioning, and how it is
>> > implemented.
>> >
>> > In conclusion, I don't think it is a good idea to implement tone mark
>> > positioning in layout engine. It would affect interoperability and
>> > complicate the impls. The positioning should be handled by fonts.
>> >
>> > However, we know that no fonts seem to support this currently. They even
>> > display a rotated tone mark in vertical text. For this, I suggest we use
>> > polyfiller to do the positioning. It would be easier to implement this
>> > in
>> > JavaScript and DOM, a polyfiller also provides more flexiblilty for
>> > authors
>> > to control over the behavior. Once the fonts start supporting this,
>> > authors
>> > can simply remove the polyfiller.
>> >
>> > The attachment is a simple polyfill demo for tone mark positioning. It
>> > seems
>> > to work almost fine with Trident and WebKit (with a little problem with
>> > Gecko, though, because of the incomplete ruby impl)
>> >
>> > - Xidorn
>> >
>> > [1]:
>> > http://dev.w3.org/csswg/css-ruby/#valdef-ruby-position-inter-character
>> >
>> > <tone-mark-positioning.html>
>
>
Received on Thursday, 29 January 2015 17:48:08 UTC

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