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

On Sat, Jan 31, 2015 at 10:01 PM, Bobby Tung <bobbytung@wanderer.tw> wrote:

>
>
> Xidorn Quan <quanxunzhen@gmail.com> 於 2015年1月31日 上午6:30 寫道：
>
> 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:
>>>
>>>
>>> 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?
>
>
> I think we can provide a subset only contains Bopomobo and tone marks with
> GPOS feature as a webfont. Authors add CSS font-family value and it's done.
> For EPUB, we can embedded the subset into the package. But we should find
> out what GPOS feature fit the usage, or need a new feature registered?[1]
>

It seems there is an existing feature named 'mark' [1], whose description
seems to match what we need here. Maybe we can use this one?

[1] https://www.microsoft.com/typography/otspec/features_ko.htm#mark

- Xidorn