Norbert:
here at Debian recently a problem surfaced with respect to the
OpenType TeX Gyre fonts.
The problem is that the ligatures are named
f_i
etc while display engines like poppler, as well as the orginal
PostScript fonts, use
fi
etc.
In Debian and Ubuntu, currently the TeX Gyre fonts provide the
*standard* postscript fonts, due to be considered generally
better.
But that means, that at the current moment of one uses the TeX Gyre
fonts as a replacement for the PS fonts, the ligatures will not be
rendered at all.
[...]
Related bug reports are:
* Debian BTS: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=742767
* FreeDesktop: https://bugs.freedesktop.org/show_bug.cgi?id=73291
Dear Colleagues,
we are more than happy that the TeX Gyre collection
of fonts has been have been chosen as a default
font set in Debian distribution. And we are
sorry that we haven't predicted the problem
of the discrepancy between the "new" and "old"
ligatures name.
Our idea was to provide "partially new" fonts.
More precisely, we have assumed that the fonts in the
Type 1 format should be "as compatible as possible"
with the Adobe original fonts. In particular, we tried
to preserve (with some exceptions, due to obvious Adobe's
bugs) the original font metric and, moreover, we used the
"old-style" names for ligatures.
The fonts in the OTF format, however, we considered "new" ones
(note, e.g., that they have Unicode tables and that they are equipped
with the OTF typografic features, both absent from the original
Adobe fonts) and, therefore, following Adobe's recommendations
for the glyph naming in new fonts (see the mentioned by Karl
documentation http://sourceforge.net/adobe/aglfn/wiki/AGL%20Specification
and also Adam Twardoch's John Hudson's comments --
http://typophile.com/node/18452 and
http://typophile.com/node/33330 , respectively),
we assigned the new-style ligature names.
In the TeX Gyre Math fonts we also have used the new-style
ligature names.
Two questions:
1. What about using Type 1 fonts for "compatibility purposes"?
It seems to us taht it could be the simplest "patch", provided
the font rendering engines are able to handle conveniently
"obsolete" Type 1 fonts.
2. Does it make really sense to make a step
backward and revert to the old-style names in the OTF
TeX Gyre fonts (including TeX Gyre Math)? It is feasible,
but we are rather reluctant to introduce such a change,
as it is likely to cause fuss among TeX Gyre users.