[tex-live] Missing Ligatures after 'dvips -Ppdf'

[Zdenek Wagner]

2009/5/4 Robin Fairbairns <Robin.Fairbairns at cl.cam.ac.uk>:
> Uwe Siart <uwe.siart at tum.de> wrote:
>
>> in recent texlive with kpfonts v3.02 all ff-Ligatures are missing in the
>> .ps output when the 'Ppdf' option is used with dvips. A minimal example
>> to reproduce the defect is
>>
>> % ---------------------------
>> \documentclass{scrartcl}
>> \usepackage[latin1]{inputenc}
>> \usepackage[T1]{fontenc}
>> \usepackage{kpfonts}
>> \begin{document}
>>   Koffer
>> \end{document}
>> % ---------------------------
>>
>> It appears that this is due to character shifting enabled in config.pdf
>> (option "G"). Comparison to MiKTeX shows that this option has been
>> disabled there hence the problem does not appear in MiKTeX.
>>
>> I'm unable to assess whether this is an issue with kpfonts 3.02 or
>> whether character shifting is (in general) a risky action which should
>> be avoided at all. Therefore I'd like to encourage you to check whether
>> texlive should follow MiKTeX's modality and disable character shifting
>> in config.pdf.
>
> character-shifting deals with a problem in acrobat 3 (i think it was).
> it has never been safe when used with an adobe-standard-encoded type 1,
> and one might expect it to be far worse than "just" broken "f" ligatures
> with a font family as complicated as kpfonts.
>
Character shifting CANNOT break ligatures. Dvips does not know that it
places a ligature. TeX looks into the tfm files and finds that f+f
form a ligature and finds the glyph code of the ff ligature. DVI then
contains the ligature, not two f characters. If you do not have the
ligature in your output, it has nothong to do with dvips. The source
of the problem is tfm. there may just be some kerning that makes two f
characters look as a ligature. You can disassemble the tfm file by
tftopl and look whether the ligatures are defined.

> one might even think one could do away with it in all standard configs,
> but there could be screams from the "we must continue to support people
> running dos 2 on an 80186" people.
>
> however, there's still the "D 8000" in the config, which aims to achieve
> dvipsone's sort of glyph placement accuracy.  perhaps we could have a
> config.hires that contains nothing but that?
>
> r
>



-- 
Zdeněk Wagner
http://hroch486.icpf.cas.cz/wagner/
http://icebearsoft.euweb.cz