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

On Sat, Jan 31, 2015 at 4:43 AM, Richard Ishida <ishida@w3.org> wrote:

> On 29/01/2015 23:30, Xidorn Quan wrote:
>
>> On Fri, Jan 30, 2015 at 4:47 AM, Koji Ishii <kojiishi@gmail.com
>> <mailto:kojiishi@gmail.com>> wrote:
>>
>>     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.
>>
>>
>> I'm still not convinced. I don't see any analysis in this article about
>> why positioning tone mark cannot be done by font with existing features.
>> From the question "Can tone positioning be done using font metrics?", if
>> I read correctly, he pointed out three difficulties:
>>
>> (1) There are too many characters in Chinese font, which makes it hard
>> to mark every character with annotation.
>> (2) There are fonts with annotation marked, but they are suffered from
>> heteronyms.
>> (3) Reordering of code points is usually done by layout engine instead
>> of fonts.
>>
>> Please tell me if I missed something important.
>>
>> The first two points don't make sense to me. We don't hope characters to
>> be marked with the whole annotation. We simply hope fonts have special
>> values for positioning tone marks to be besides bopomofo. There are only
>> less than 40 bopomofo characters, and 4 tone marks. Hence there are no
>> more than 160 combinations (even less, because the 20+ consonants won't
>> be combined with tone marks, and light tone is not combined besides
>> bopomofo, hence actually only about 50). I'm not familiar with OpenType
>> features, hence I don't know if it is feasible to handle this with
>> features like GPOS (I suspect it is), but it doesn't seem to be harder
>> than positioning requirements of scripts like Arabic. In addition, given
>> the small number of combinations, I guess it could at least be handled
>> with GSUB.
>>
>
> Thanks for this comment. I think you may be right. I had been coming at
> the problem after thinking of the fonts out there that encode the actual
> bopomofo needed for each character within the font. But I think you're
> right that that's not what we need here.
>
> The bopomofo to be associated with a character is spelled out by the ruby
> markup.  I guess all that's needed is a way to render the tone marks in
> relation to the bopomofo characters.
>
> In that case, actually, I suppose it would even be possible, as a stop
> gap, to speed up the process of adoption by creating small fonts that just
> do bopomofo and using font-family to apply those to the ruby annotations.
> Such fonts may be relatively easy to produce and distribute, and especially
> if they are free to use they could therefore allow people to start using
> bopomofo ruby sooner rather than later.


Yes, that's a great idea. And I guess it is also possible to develop a tool
which extracts bopomofo characters and tone marks from a font, and
generates the required bopomofo font automatically, so that authors can
make their pages look more consistent?

- Xidorn