path: root/Build/source/texk/afm2pl/afm2pl.txt

afm2pl

Siep Kroonenberg

   <[1]ntg-afm2pl@ntg.nl>

   Copyright © 2004 Siep Kroonenberg
     _________________________________________________________________

   Table of Contents

   [2]afm2pl - convert AFM font metrics to TeX pl font metrics

Name

   afm2pl -- convert AFM font metrics to TeX pl font metrics

Synopsis

   afm2pl [-p encoding_file ] [-o] [-e extension_factor ] [-s
   slant_factor ] [-f font_dimensions ] [-k] [-m letter_spacing ] [-l
   ligkern_spec ] [-L ligkern_spec ] {input_file[.afm]}
   [output_file[.pl]]

   afm2pl {[--help] | [--version]}

Description

   afm2pl converts an afm (Adobe Font Metric) file into a pl (Property
   List) file, which in its turn can be converted to a tfm (TeX Font
   Metric) file. It preserves kerns and ligatures.

   afm2pl is meant to be a replacement for afm2tfm, on which it is based.
   With afm2tfm, preserving kerns and ligatures is possible only in a
   roundabout way.

   For text fonts, Y&Y's texnansi is the recommended encoding to be used
   with afm2pl. This gives you a good character set with all the more
   important accented characters and many typographic symbols available
   as single characters, without a need for either virtual fonts or a
   separate text companion font.

   Full LaTeX support for this encoding is available in the form of the
   texnansi package, which is already part of TeX Live and teTeX. These
   distributions also contain the encoding file texnansi.enc.

   The distribution contains uppercased and lowercased versions of
   texnansi, viz. texnanuc.enc and texnanlc.enc, to allow font-based
   rather than macro-based uppercasing and lowercasing, and the familiar
   old ot1 encoding plus some variations in PostScript .enc format (I
   included these because they seem to be absent from teTeX/TeX Live).

   Return value: 0 if no error; a negative number indicating the number
   of missing glyphs if conversion was successfull but glyphs are
   missing, and 1 in case of error.

Options

   -p encoding_file
          The default is the encoding specified in the afm file, which
          had better match the encoding in the fontfile (pfa or pfb). The
          generated mapfile entry (see below) instructs pdftex or the dvi
          driver to reencode the font on the fly. On-the-fly reencoding
          does not require virtual fonts.

   -o
          Use octal for all character codes in the pl file.

   -e extend_factor
          Widen or narrow characters by extend_factor. Default is 1.0
          (natural width). Not recommended, except that arguably a
          narrowed Courier is less jarring than a full-width Courier,
          when used in combination with a normal proportional font. For
          Courier, choose .833 to match the width of cmtt.

   -s slant_factor
          Oblique (slant) characters by slant_factor. Not recommended.

   -f font_dimensions
          font_dimensions is a comma-separated list of up to three
          integers, for successively stretch and shrink of the interword
          space, and extra space for between sentences (cf. spacefactor).
          Default values: one-half, one-third and one-third of the width
          of a space. Specify just a non-default stretch and shrink with
          e.g. 150,70 and just a non-default extra space with ,,10. For a
          fixed-pitch font this parameter is ignored.

   -k
          Keep original ligatures. This option only has effect in
          combination with positive letterspacing; see the section on
          [3]letterspacing and extra ligkern info.

   -m letter_spacing
          Letterspace by letter_spacing/1000 em (integer). This is useful
          for making all-caps typesetting look better. Try a value of
          e.g. 50 or 100. But see the section on [4]letterspacing and
          extra ligkern info for details.

   -l ligkern_spec, -L ligkern_spec
          See the section on [5]extra ligkern info for details.

   -V
          Verbose. If turned on, it reports the number of missing glyphs
          to stderr and their names to stdout. This is not particularly
          logical, but this way the glyph names can be captured even
          under Windows.

   --help
          Display a short usage message.

   --version
          Display the version number of afm2pl.

Mapfile entries

   afm2pl writes a mapfile entry to a file with the same basename as the
   pl output file, but with extension .map. It can be used for the dvips
   mapfile and for the pdftex mapfile, although, in case of a
   geometrically transformed font, it may be better to remove the
   PostScript name for a pdftex mapfile entry. It is assumed that the pfb
   file has the same basename as the afm file and must be downloaded. You
   may have to hand-edit this entry.

   You can configure dvips and pdftex to read this additional mapfile or
   otherwise add the entry to an existing mapfile. It appears that pdftex
   automatically will consult a mapfile xxx.map for a font xxx.

Extra ligkern info

   Most users are well-advised to leave this mess alone and to accept the
   default behavior.

   The ligatures and kerns present in the afm file can be modified in
   various ways. Default, the encoding file is scanned for extra ligkern
   specifications, whose format will be described below. If there are no
   ligkern specifications in the encoding file, then extra ligkern
   specifications will be read from a file default.lig. A value of 0 for
   ligkern_spec means that the ligatures and kerns from the afm file
   won't be tampered with and a value of 1 specifies default behavior.
   One can also specify a comma-separated list of files with extra
   ligkerns specs.

   If afm2pl is compiled with the kpathsea library, then these files will
   be searched for under $TEXMF/fonts/lig.

   Note that ligatures and kerns are hints for the typesetting
   application; there is no need to download this information to the
   printer or to make it available to a dvi driver.

   The parser for ligkern info has been inherited from afm2tfm virtually
   without change. A ligkern specification can have one of the following
   forms:
glyph_name1 glyph_name2 lig_op glyph_name3 ;

   This specifies a ligature. Possible values for lig_op are =:, |=:,
   |=:>, =:|, =:|>, |=:|, |=:|> and |=:|>>. These correspond to LIG,
   /LIG, /LIG>, LIG/, LIG/>, /LIG/, /LIG/>, /LIG/>> in .pl syntax; see
   the pltotf documentation and the .lig files in the distribution.
glyph_name1 <> glyph_name2 ;

   Kern glyph_name1 as glyph_name2.
glyph_name1 {} glyph_name2 ;

   Remove the kern between glyph_name1 and glyph_name2. A value of * for
   either glyph name is interpreted as a wildcard.
|| = glyph ;

   Set the (right) boundary character to glyph. glyph may be either a
   glyphname or a slot in the encoding vector. Choosing a glyph which
   doesn't occur in the output encoding is equivalent to not specifying a
   boundarychar at all. It is ok to pick an encoded glyphname which does
   not occur in the afm. In fact, this is what default.lig does: || = cwm
   ;.

   You can copy the kerns of an unencoded character to the boundarychar:
|| <> space ;

   This ligkern specification should occur before the one that deletes
   space kerns.

   A ligkern specification should be contained within one line. One line
   may contain several ligkern specifications, separated by spaces. Note
   that ; (space followed by semicolon) is considered part of the ligkern
   specification. See the lig files included in this distribution.
   Example:
one {} * ; * {} one ; two {} * ; * {} two ;

   Lines with ligkern specifications inside an encoding file should start
   with % LIGKERN . Ligkern specifications in a lig file may optionally
   start this way.

Letterspacing and extra ligkern info

   Letterspacing has various side-effects for ligkern info. Instead of
   simply applying the extra ligkern info (see previous section), the
   following is done:
    1. In case of positive letterspacing, native ligatures are removed,
       unless the -k option is specified.
    2. Extra ligkern info is applied as usual, except that in case of
       positive letterspacing different defaults apply: -l 0 is quietly
       ignored, ligkern comments in the encoding file are ignored, and
       defpre.lig is read instead of default.lig.
    3. Letterspacing is applied. This adds a lot of kerns, and modifies
       existing kerns.
    4. The extra ligkern info specified with -L is applied. The only
       ligkern specs which are allowed here, are removals of kerning
       pairs (with the {} operator). Values 0 and 1 have a similar
       meaning as for the -l parameter. The tfm format has room for only
       about 180x180 ligatures and kerning pairs. This is enough for OT1
       encoding, but for texnansi encoding quite a few ligkern
       specifications have to be removed. The pltotf program will remove
       all ligkern info if too many ligatures and kerns remain. The
       default lig file is defpost.lig. This file throws out kerning
       pairs which are unlikely to be involved in letterspacing, such as
       kerns involving accents or kerns with a punctuation character or
       right bracket at the left. It does not add letterspacing kerns
       involving boundarychars. Instead, fontspace is increased by twice
       the letterspacing. defpost.lig throws out enough kerns in case of
       texnansi encoding. With other encodings, you may have to throw out
       additional kerning pairs.

Font-based upper- and lowercasing

   The distribution includes encoding vectors texnanuc.enc and
   texnanlc.enc which produce all-uppercase and all-lowercase fonts. The
   distribution contains an example ucshape.tex on how to use such fonts
   with LaTeX font selection.

   The principal uses for an all-uppercase font are page headers and
   section heads. If these contain math, then macro-based uppercasing
   would create unpleasant complications.

The sz ligature ß

   Note that the texnanuc encoding provides no glyph for the sz ligature
   ß; you'll either have to substitute ss or provide a macro-based
   solution. The following code uses either the usual glyph or
   substitutes the letters ss, depending on whether the glyph exists in
   the current font:

\def\ss{%
  \setbox0\hbox{\char25}%
  \ifnum\wd0=0 ss\else\box0\fi
}

   In LaTeX, this code appears to work well enough, although on occasion
   you may need to insert \protect. A better solution might involve the
   sixth parameter of the \DeclareFontShape macro, but I failed to get
   that to work.

Afm2pl, fontinst and artificial smallcaps

   Afm2pl currently doesn't do virtual fonts. That means that for things
   such as artificial smallcaps you have to turn elsewhere, e.g. to the
   fontinst package, which is part of any mainstream TeX distribution.

   Look under texmf/tex/fontinst for fontinst support files, which allow
   you to generate a smallcaps font (tfm and vf files) from an
   afm2pl-generated tfm file. This package only supports texnansi
   encoding.

   There should be no real problem in doing the same for OT1 encoding.
   However, there are several variations of the OT1 encoding to take care
   of. Also, there are as far as I know no officially sanctioned
   PostScript names for all the variations of the OT1 encoding; the
   fontinst names contain spaces and are therefore not useable as
   PostScript names.

Future plans

   I am considering a revision which makes afm2pl a more complete
   replacement for afm2tfm. In that version, afm2pl can optionally create
   a second, virtual font, possibly with a different encoding and
   possibly letterspaced. The current option of non-virtual letterspacing
   via kerns will be dropped. If the encodings differ then it is assumed
   that the virtual font is intended as a small-caps version of the main
   font, and a scaling parameter can be specified for non-matching
   glyphs.

Copyright

   The afm2pl distribution is subject to the GNU General Public Licence
   (GPL). Please refer to the file COPYING for details.

   The afm2pl homepage is [6]http://www.ntg.nl/afm2pl.html.

References

   1. mailto:ntg-afm2pl@ntg.nl
   2. file://localhost/home/siepo/afm2pl/afm2pl-0.7/afm2pl.html#id2447180
   3. file://localhost/home/siepo/afm2pl/afm2pl-0.7/afm2pl.html#lspace
   4. file://localhost/home/siepo/afm2pl/afm2pl-0.7/afm2pl.html#lspace
   5. file://localhost/home/siepo/afm2pl/afm2pl-0.7/afm2pl.html#lspecs
   6. http://www.ntg.nl/afm2pl.html