Breaking Ligatures in LaTeX
Clark Dixon
certain combinations of characters as a single special character rather
than individuals (reducing the amount of space between them). Some
examples are ff, fi, fl, ffi and ffl.
This poses a problem within my firm, because of old printers that cannot
support the special characters. I discovered that on a case by case
basis, this behavior can be suppressed by insering "\/" between the
characters of the combination (e.g., f\/f instead of ff). What I am
looking for, however, is a way to turn this behavior off globally, so
that we do not have to rely on individual authors to recognize and
"correct" every occurence of these combinations in their text.
My first thought was to write a simple sed script (I'm in a Unix
environment) to do global replacements of each combination. This
script then could be used as a front-end filter to latex. However, the
problem that arises immediately is how to guarantee replacement of the
combinations in the actual text without making changes to anything else
in the files (e.g., LaTeX commands).
Does anyone have any suggestions?
David Carlisle
> LaTeX (I guess actually it's TeX) makes use of ligatures, printing
> certain combinations of characters as a single special character rather
> than individuals (reducing the amount of space between them). Some
> examples are ff, fi, fl, ffi and ffl.
>
> This poses a problem within my firm, because of old printers that cannot
> support the special characters. I discovered that on a case by case
> basis, this behavior can be suppressed by insering "\/" between the
> characters of the combination (e.g., f\/f instead of ff). What I am
> looking for, however, is a way to turn this behavior off globally, so
> that we do not have to rely on individual authors to recognize and
> "correct" every occurence of these combinations in their text.
>
It is not TeX that does the ligatures but the fonts themselves.
(well TeX does it but only if the fonts specify that) So I don't
understand your comment. If the fonts you are using on your `old
printers' haven't got ligatures, then assuming that the correct
metrics have been set up then TeX won't insert any ligatures when
using those fonts.
David
Louis Vosloo
> LaTeX (I guess actually it's TeX) makes use of ligatures, printing
> certain combinations of characters as a single special character rather
> than individuals (reducing the amount of space between them). Some
> examples are ff, fi, fl, ffi and ffl.
> This poses a problem within my firm, because of old printers that cannot
> support the special characters.
Can you explain this? If you are using CM fonts e.g. there is
no reason why those characters should be any more difficult than
others. And if you are using fonts that don't have those characters
then the TFM file won't have ligatures for them.
> I discovered that on a case by case
> basis, this behavior can be suppressed by insering "\/" between the
> characters of the combination (e.g., f\/f instead of ff). What I am
> looking for, however, is a way to turn this behavior off globally, so
> that we do not have to rely on individual authors to recognize and
> "correct" every occurence of these combinations in their text.
> My first thought was to write a simple sed script (I'm in a Unix
> environment) to do global replacements of each combination. This
> script then could be used as a front-end filter to latex. However, the
> problem that arises immediately is how to guarantee replacement of the
> combinations in the actual text without making changes to anything else
> in the files (e.g., LaTeX commands).
> Does anyone have any suggestions?
If you have to do this (and as I indicated I am not sure I
can understand why) then the best answer is to remove those
ligatures from the TFM files. I guess this means
recreating them from AFM, or taking the old ones, passing
them through TFtoPL, editing the PL file to remove the
ligatures and back through PLtoTF.
Rebecca and Rowland
[snip]
> If you have to do this (and as I indicated I am not sure I
> can understand why) then the best answer is to remove those
> ligatures from the TFM files. I guess this means
> recreating them from AFM, or taking the old ones, passing
> them through TFtoPL, editing the PL file to remove the
> ligatures and back through PLtoTF.
This is one job that's perfect for fontinst; you need to produce etx
files that lack the ligatures, and then run the cm pl files through
fontinst. (there's a certain amount of mucking around and you'll
probably want to get vfs out of fontinst).
Rowland
--
Remove the animal for my email address: reb...@astrid.dog.u-net.com
Sorry - the spam got to me. PGP pub key A680B89D
UK biker? Join MAG and help keep bureaucracy at bay
http://dredd.meng.ucl.ac.uk/www/mag/mag.html
David Carlisle
> Louis Vosloo <sup...@YandY.com> wrote:
>
> [snip]
> > If you have to do this (and as I indicated I am not sure I
> > can understand why) then the best answer is to remove those
> > ligatures from the TFM files. I guess this means
> > recreating them from AFM, or taking the old ones, passing
> > them through TFtoPL, editing the PL file to remove the
> > ligatures and back through PLtoTF.
>
> This is one job that's perfect for fontinst; you need to produce etx
> files that lack the ligatures, and then run the cm pl files through
> fontinst. (there's a certain amount of mucking around and you'll
> probably want to get vfs out of fontinst).
>
> Rowland
>
But you don't need any vfs. Just tfms without the ligtable.