[XeTeX] XeTeX 0.8 available -- now with OpenType support :-)

[Jonathan Kew]

On 1 Jun 2004, at 11:48 pm, Somadevah at aol.com wrote:

> Many thanks for providing this excellent version of TeX.

You're welcome!

>  Is there a way to use TeX's diacritics in unicode files? If I try to 
> add say, \={a} of \d{n} or something like that in the midst of unicode 
> text I get gibberish output or it seems cmr is substituted for the 
> diacritic. This applies both to ATSUI fonts like Hoefler or OT fonts 
> like Adobe Garamond Pro.

The plain TeX control sequences for accents, such as \= or \d, are 
specific to the (idiosyncratic) font encoding of the CM fonts. 
(Presumably LaTeX packages for different font families with different 
encodings redefine these commands in some way.)

When you're using a font like Hoefler or Adobe Garamond in XeTeX, 
however, all font access is through Unicode character codes. The 
"normal" way to get an 'a' with macron would be to directly use the 
Unicode character U+0101, 'ā', in the document. (Or the sequence <0061, 
0304>.) This should work with any Unicode-compliant font that supports 
this character.

If you want to be able (for portability, perhaps) to continue using 
plain TeX control sequences to generate accents, you could provide 
definitions that use the appropriate Unicode values. Something like:
	\font\x="Lucida Grande" at 12pt \x
	\def\=#1{#1^^^^0304}
	\def\d#1{#1^^^^0323}
	This is \={a} te\={s}t for acce\d{n}ts \={i}n Unicode fonts.
	\bye
Note that this is still dependent on the particular repertoire of 
Unicode characters the font actually supports. So this example works 
better with Lucida Grande than with Hoefler Text, which doesn't seem to 
support the dot-below, and produces a spacing macron rather than an 
overstrike where no precomposed character is available (e.g., when 
trying to use the macron on 's').

>  I also just notice that in Apple's qwerty Devanagari keyboard layout 
> it is impossible to type the ligature "dbhy" (d-f-B-f-y) as a single 
> glyph. Does anybody know how to get this (in Sanskrit very common) 
> ligature as a glyph? The glyph is clearly there in Devanagari MT, I 
> checked with fontlab, but since it has no individual unicode slot I 
> have no idea how to call it if the combining mechanism does not 
> produce it?

It seems that the AAT tables in the font don't actually access this 
glyph. There's a font feature "Conjuncts=Additional Conjuncts" that you 
can turn on in Devanagari MT, but when I try this I *still* don't get 
that ligature. This would be a question for the font people at Apple, I 
guess.

(In XeTeX, if you *really* want to see the glyph, you could produce it 
with "\XeTeXglyph 279", or 281 if you prefer the alternate glyph shape, 
but that's absolutely not how you want to be encoding documents, and 
it's dependent on the exact version of the font that you have; the 
glyph ID may not stay constant across different versions.)

Jonathan