[XeTeX] strande behavior of Linux Libertine fonts with optio Fractions=On

[Khaled Hosny]

On Sun, Jan 16, 2011 at 11:09:40AM -0600, mskala at ansuz.sooke.bc.ca wrote:
> On Thu, 13 Jan 2011, Fr. Michael Gilmary wrote:
> > >   I couldn't find the source code for the OpenType features
> > > in Latin Modern Roman;
> 
> > Voilà!
> >
> > > > > otfinfo -f lmroman10-regular.otf
> 
> I'd been hoping for the source code as such - i.e. the *.fea files.
> Looking at the substitution tables after they're compiled into the *.otf
> files can be difficult with a complicated feature like arbitrary-length
> fractions; the table format isn't designed to be human-readable.
> 
> Nonetheless, I did take a look at the tables for Latin Modern Roman in
> FontForge, and it appears to me that it's just substituting precomposed
> glyphs - so that "one fraction two" will become "onehalf" and so on, but
> it won't work on arbitrary fractions with a large number of digits.  I
> haven't dug into Junicode myself, but Alexey Kryukov's posting suggests
> that that's how Junicode does it as well.  The problem is in the
> interaction between arbitrary-length fractions and digit sequences that
> are not fractions:  I don't think it's possible to support
> arbitrary-length fractions and also leave non-fraction digit sequences
> untouched.

It can be done to some degree, see:
http://talleming.com/2009/10/01/fraction-fever-2/

(I didn't try it myself, though).

Regards,
 Khaled

-- 
 Khaled Hosny
 Arabic localiser and member of Arabeyes.org team
 Free font developer