Re: Taiwanese: unicode of o with dot right above

Date: Tue Aug 15 2000 - 13:07:35 EDT

On 08/15/2000 10:48:02 AM "Kiatgak" wrote:

>1. Can anyone kindly explain why COMBINING DOT ABOVE RIGHT was turned


>The proposal on 1997/6/22 also said: " no publication has COMBINING
>ABOVE appeared in the place of COMBINING RIGHT DOT ABOVE. Therefore it is
>inappropriate to view the proposed character COMBINING RIGHT DOT ABOVE as
>presentation form of COMBINING DOT ABOVE."

Ken can respond more fully, but it sounds like it was considered a glyph
variant of COMBINING DOT ABOVE, in spite of the above statement. The point
seems to be that the dot was simply shifted to the right to accommodate
other ABOVE diacritics. This creates a situation similar to Vietnamese, and
that relationship may be advantageous (further below).

>2. If using O/o + U+0307(COMBINING DOT ABOVE) to represent "O/o with dot
>above right", how to make them have the desired appearance?


>Peter said:
>> though it does depend upon font developers supporting a
>> language-specific behaviour

Yup. It's going to take special font/rendering support, just as is the case
with Vietnamese and some other languages (language-specific rendering
issues arise e.g. for Turkish, Serbian). Language-specific fonts are one
way to do this, but not the only way. Language-specific features and rules
within a font can also be used (where such mechanisms are supported - not
in very many places today, but hopefully increasing over time).

>So, the best way seems to request font developers to support a
>language-specific behavior. But
> a) to get the help from font developers seems very unlikely (because
>is not a general solution as adding a COMBINING DOT ABOVE RIGHT, just like
>Peter said).

Actually, the similarity of the positioning issue (horizontal movement to
avoid collision with other diacritics) with Vietnamese suggests a
possibility: if a font vendor is already dealing with this kind of
positioning issue for Vietnamese, they can just generalise their behaviours
a bit to include the combiniations needed for Taiwanese (unless there are
some conflicts, but I suspect that's not a problem). Now, this might make
as assumption: the feature that enables this kind of positioning for
Vietnamese is the same feature used for Taiwanese. In OpenType, there is a
set of features for "languages", but in practice I think they're really
denoting groups of writing systems. If the collection of rendering
behaviours for Vietnamese and Taiwanese are a common set (but, of course,
each language would use character combinations that the other doesn't),
then there's not a lot of additional work for a font developer to add the
support for Taiwanese. I'm not familiar with the details of either
Taiwanese or Vietnamese writing, so there may be reasons I'm not
considering why this couldn't work. It's just an idea.

> b) for the lesser-used languages including Taiwanese etc., there are
>no language codes for them.

Well, that's a bigger problem, and I'll be touching on that in a
presentation at IUC17.

>Maybe the final result is either we have to tolerant the dot on the above
>position or we have to create our own fonts?

Or get others to develop fonts that support Taiwanese (someone will do it
if there's a market).

>If we have to create our own fonts, what are the criteria in order to
>conform to Unicode standard? (Available fonts currently are all defined by
>their own special codes.)

(I was going to add some additional comments, but don't have time right
now. I may get back on this.)

- Peter

Peter Constable

Non-Roman Script Initiative, SIL International
7500 W. Camp Wisdom Rd., Dallas, TX 75236, USA
Tel: +1 972 708 7485
E-mail: <>

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