Re: Vallian (was: How to minimize "words")

On 26/02/07, Philip Newton <philip.newton@...> wrote:
...
> *nods* and Unicode also caters for that -- as best I remember, it has
> different "weights" for various kinds of diacritics specifying which
> ones should be closer to the base character, so diacritics should
> stack in the correct order regardless of which order you encode them
> in (e.g. a + combining diaeresis + combining tilde should "do the
> right thing", at least according to Unicode, though I don't remember
> which order they think is the correct one in this case -- combinations
> of letter + diacritic above + diacritic below or vice versa should
> definitely work fine, though, if your rendering engine's up to it).
No:
a + combining diaeresis + combining tilde has the tilde atop the diaresis
a + tilde + diaeresis has the diaresis atop the tilde.
Who is Unicode to say you can't have a fronted nasalised vowel as
easily as you can have a nasalised fronted one?

But there's some combining characters that combine over two letters.
They always come at the very top; that's probably what you're thinking
of. Also, Unicode does specify a way for diacritics to stack, but
that's only in terms of where they go: an acute accent always goes
directly above a circumflex according to Unicode, which leads to
precisely the problem you mention below:

> (Though the Vietnamese preference for tone markes such as acute and
> grave to be next to vowel quality modifiers such as a circumflex are,
> I believe, not specifically catered for; but in any event, such
> language-specific behaviour is typically relegated to rendering
> engines which are more aware of such things, rather than something
> Unicode -- which is intended for all languages -- specifies.
Indeed. Tho there are two characters COMBINING ACUTE/GRAVE TONE MARK,
which combine the way Vietnamese wants, but they're still declared to
be equilavent to the non-TONE form.

The SIL fonts Charis and Doulos treat the TONE/non-tone characters
equivalently, but provide a mechanism for enabling Vietnamese mode,
which makes them both kern to the right/left. Gentium treats them
differently, with the TONE characters doing what Vietnamese expects,
and the other ones stacking vertically. I'm pretty sure Charis and
Doulos are right in this regard...


--
Tristan.

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