Re: Why doesn't Ideographic (ID) in UAX#14 have half-width katakana?

# Sorry, I slipped to consider about the
# big picture attachment. I reduced the
# image size and resend to Unicode mailing
# list.

Kato-san,

Thank you very much for prompt response.

> This is a sample for line break of half-width katakana. (There is
> good sample by web browser implementation)
> http://mxr.mozilla.org/mozilla-central/source/layout/reftests/line-breaking/ja-3.html

I wish if the sample text is longer to show
the line breaking behaviour. I attached
jugem.txt and the screenshot by Firefox and
Chromium.

> Firefox and IE11 define half-width katakana as ID. The line break of
> half-width katakana is same as full-width katakana.
> Chrome doesn't define it as ID. Half-width katakana isn't line break
> per character.

Oh, Google Chrome could not break half-width katakana
text by per-character line breaking! It is very good
example showing that the lack of explicit definition
caused the incompatibility (and inconvenience). I'm
sorry for troubling you about the explanation. I agree
with your proposal to add halfwidth katakana to ID-class,
even if further discussion is needed for other scripts.

Regards,
mpsuzuki

Makoto Kato wrote:
> Hi, Suzuki-san. Thank you for reply.
>
>> At present, I have no objection to add halfwidth katakana
>> to ideographic-class in UAX#14, but I'm unfamiliar with the
>> (negative) impact caused by the lack of halfwidth katakana
>> in it. Could you tell me if you know anything?
>
> Since half-width katakana isn't ID, it isn't break line like
> full-wdith katakana.
>
> This is a sample for line break of half-width katakana. (There is
> good sample by web browser implementation)
> http://mxr.mozilla.org/mozilla-central/source/layout/reftests/line-breaking/ja-3.html
>
> Firefox and IE11 define half-width katakana as ID. The line break of
> half-width katakana is same as full-width katakana.
> Chrome doesn't define it as ID. Half-width katakana isn't line break
> per character.
>
> Although I read JIS X 4051, it doesn't define that half-width katakana
> and full-width katakana are differently.
>
>
>> I guess, the inclusion or exclusion in other classes, like,
>> AI, AL, CJ, JL, JV, JT, SA might be quite important to realize
>> the appropriate line breaking, but the inclusion or exclusion
>> in ID-class does not seem to be important. If the inclusion
>> in ID-class is important, more characters (e.g. Bopomofo)
>> should be considered for full coverage. How do you think of?
>
> My discussion is why half-width katanaka character isn't same class of
> full-width katakana character. In this case, half-width katakana
> originally defines as AL at current spec. So when moving to ID, break
> rule is strongly changed. (non-break -> break before or after).
>
>
> -- Makoto
>
> On Tue, Apr 28, 2015 at 12:14 PM, suzuki toshiya
> <mpsuzuki_at_hiroshima-u.ac.jp> wrote:
>> Kato-san,
>>
>> At present, I have no objection to add halfwidth katakana
>> to ideographic-class in UAX#14, but I'm unfamiliar with the
>> (negative) impact caused by the lack of halfwidth katakana
>> in it. Could you tell me if you know anything?
>>
>> I guess, the inclusion or exclusion in other classes, like,
>> AI, AL, CJ, JL, JV, JT, SA might be quite important to realize
>> the appropriate line breaking, but the inclusion or exclusion
>> in ID-class does not seem to be important. If the inclusion
>> in ID-class is important, more characters (e.g. Bopomofo)
>> should be considered for full coverage. How do you think of?
>>
>> Regards,
>> mpsuzuki
>>
>> Makoto Kato wrote:
>>> Hi.
>>>
>>> http://www.unicode.org/reports/tr14/proposed.html#ID defines Ideographic
>>> (ID). Although full-width katakana is included in ID, half-width
>>> katakana (U+FF66 and U+FF71-U+FF9D) isn't. Why?
>>>
>>> Also, Conditional Japanese Starter (CJ,
>>> http://www.unicode.org/reports/tr14/proposed.html#CJ) considers
>>> half-width variants such as half-width katakana letter small a.
>>>
>>>
>>> -- Makoto

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