Re: [Groff] using Linux Libertine with groff

[Dave Kemper]

Thanks, Tadziu, for all the info and the demo file!  A few followups
below.

> I think this is because afmtodit assumes these ligatures will be
> called "fi", "fl", "ff", "ffi", and "ffl", but in the new fonts
> they are called "f_i", "f_l", "f_f", "f_f_i", and "f_f_l".

I see.  It looks like afmtodit looks for variants with spaces in the
names, but not underscores:

$ fgrep -A6 'default_ligatures =' `type -p afmtodit`
my %default_ligatures = (
  "fi", "f i",
  "fl", "f l",
  "ff", "f f",
  "ffi", "ff i",
  "ffl", "ff l",
);

> (I believe other ligatures can't currently be used with groff.
> As far as I know, this is hardwired.)

Yes, according to "info groff gtroff fonts ligatures", those five are
the only ones supported.  A quick grep through the code shows that
src/include/font.h defines five enum values in class font, for LIG_ff,
LIG_fi, etc.  And as the above code snippet shows, those are the only
ones afmtodit looks for.

It should be fairly straightforward to add new hard-coded ligatures to
the groff source, and to afmtodit.  (A better design, though harder to
implement, would be to not hard-code ligatures at all, but have groff
query the font for available ligatures.  But it's not clear there's a
reliable way to find them: a comment in afmtodit says many AFM files
lack the correct demarcation for ligatures.)

> You have to call afmtodit with the "-i" option when generating
> the description file for the italic fonts (the manual page
> says that "-i50" was used for the standard fonts).

Thanks for the tip.  Peter and I have been discussing how best to get
install-font.sh to support this.

> I've attached a demo PDF showing the results.

Great!  What version of Libertine did you use to
generate this file?  I have 5.3.0, the most recent one on
http://sourceforge.net/projects/linuxlibertine/, but some of my ligatures
look different from (and not nearly as good as) the ones in your demo.