README for using Postscript Type1 fonts with xdvik
==================================================

Starting from version 22.39, xdvik supports direct display of
Postscript Type1 fonts via t1lib.  Unlike the bitmapped TeX PK fonts
that xdvik used to depend upon, Type1 fonts only need to be stored in
one size on disk. This means no more waiting for mktexpk runs when
viewing DVI files with previously unused fonts or at a different
resolution, less hassle with temporary directories filling up with
PK files, etc.

To be able to support Type1 fonts, xdvi needs a xdvi.cfg file. The
standard `make install' process will copy the file from texmf/xdvi.cfg
which is suitable for recent teTeX distributions (starting from teTeX
>= 1.0). (If the file exists already and has been modified from the
original, the modified file will not be overwritten). Apart from the
section `Debugging your font setup', this README contains mostly
instructions for versions of teTeX older than 1.0.x or non-teTeX
systems; users of teTeX >= 1.0.x should ignore these instructions,
and only consult the `Debugging' section in case of problems with
the Type1 fonts setup.

Note that xdvi can always use a TeX bitmap (PK) font as a fallback
(produced via mktexpk, which in turn invokes ps2pk or gsftopk), so
it's not vital that xdvi is configured for Type1 fonts.  However, for
the reasons mentioned above, setting up xdvi properly for Type1 fonts
is usually preferable.


==========================================================
Instructions for users of older teTeX versions (< 1.0), or
non-teTeX systems:
==========================================================

Xdvi needs to load all Type1 fonts from disk, which means that it
(just like dvips) needs to translate the TeX names for fonts to
filenames, load encoding vectors according to map files and so on.
But unlike dvips, which produces Postscript code for printers with
built-in fonts, xdvi has _no_ builtin fonts, and thus cannot share
all font maps with dvips.
The main difference is that fontmaps for xdvi always need to contain
the name of a `real' Type1 font file (a .pfa or .pfb file) at the end
of the line, e.g. `utmr8a.pfb' in the following case:

   ptmr8r NimbusRomNo9L-Regu "TeXBase1Encoding ReEncodeFont" <8r.enc <utmr8a.pfb

whereas dvips would only need the font file name for embedding the font
into the PS file; otherwise, the font will be treated as `printer
resident'.

If you don't want to use Type1 fonts, simply create a empty xdvi.cfg
file in the location pointed to by the XDVIINPUTS environment variable
(this variable can also be defined in texmf.cnf).

Otherwise, the xdvi.cfg file should list the map files (.map extension)
that can be used by xdvi.  The file `xdvi.cfg' in the texk/xdvik/texmf-alt/
subdirectory of the xdvik distribution contains a default configuration
that can be used for your own customizations.  The xdvi.cfg file
installed by the standard `make install' process is only suitable for
more recent versions of teTeX, as mentioned above, so you'll need to
copy this file manually into the directory pointed to by XDVIINPUTS.

The sections `Fontmap file format' below and the dvips documentation
contain more information on the fontmap file format.


=================
Font Search Order
=================

The order in which xdvi tries to load a font file is:
1. Virtual fonts
2. Type1 fonts
3. PK fonts
4. (If xdvi was compiled with gf support:) GF fonts

For example, consider the search for TeX's default font `cmr10'.  In
most texk/teTeX installations the file cmr10.pfb is present in the
texmf tree.  This means that it is found at step 2 in the search and
the Type1 font is used.  Currently xdvi handles fonts with no
"implied" encoding (such as cmr10) without configuration.  Most texk and
teTeX installations come with the Blue Sky Research/Y&Y Type1 versions
of Knuths fonts, and xdvi will be able to use them with no further
action.

For fonts with an "implicit" encoding such as ptmr8r (Postscript Times
Roman, 8r encoded), xdvi also needs to know about the 8r encoding,
and be able to find a Type1 font file called ptmr (ptmr.pfa or
ptmr.pfb). The file xdvi.cfg contains a list of these encodings and
the corresponding dvips encoding files, which can be used by xdvi
as well.

The 35 `standard Postscript fonts', such as Times Roman, are are
usually available under a different name for previewing the file with
ghostscript. These font files can be used by xdvi, too, but they need
to be copied to a place where xdvi can find them.  This is already
the case by default in newer TeX distributions such as teTeX-beta or
teTeX >= 1.0 or TeXLive >= 6b. Users of older systems can use the
`t1mapper' script to copy/symlink the required files to a directory
where xdvi can find them; please see the file README.t1mapper and the
manual page of t1mapper for more information.


===================
Fontmap file format
===================

In principle Xdvi only accepts a subset of the fontmaps used by dvips
and pdftex.  In practice the restrictions are not very restraining.
For a description of the font map file syntax, see the `psfonts.map'
section of the dvips manual (dvips.{texi,dvi,pdf}).

Xdvi accepts fontmaps that obey these rules:

1. The vector files must have a .enc extention or be included by the
   <[ ... syntax in the fontmap.  Encoding is optional.  The ReEncodeFont
   keyword and its argument is tolerated, but it is _ignored_.  xdvi
   looks for a <foo.enc or <[foo to determine the encoding vector, and
   re-encode the font.

2. The other file in the map line must be a font file in pfa or pfb
   format. The extention need not be included for the sake of xdvi,
   but dvips and pdftex might need it, so better include it when using
   shared fontmap files.  An explicit font file name is required by
   xdvi since xdvi does not have any builtin fonts.

3. There may not be any other input files on a fontmap line.

   Xdvi is not a printer and cannot accept arbitrary postscript
   prologues or setup things in fontmaps.

4. Xdvi decodes the ExtendFont and SlantFont commands in the quoted
   postscript code and the extention factor and slanting is applied
   to the font when displayed.  Any other magic done by the quoted
   postscript code won't be understood by xdvi.


=========================
Debugging your font setup
=========================

If your Type1 font setup doesn't work, please check the following:

1. Make sure that xdvi finds your xdvi.cfg file (it will print a warning
   to stderr if it doesn't). The file should be located in a directory
   referenced by the XDVIINPUTS variable, which can be either set in your
   shell environment, or in your texmf.cnf file.

2. Make sure that xdvi can find the map files listed in your xdvi.cfg
   file (in the `dvipsmap' entries). Use the `-debug 3968' option for
   xdvi to see where it searches for the files. E.g., with the (ba)sh
   shell:

   $ xdvi -debug 3968 ~/test.dvi 2>&1 | grep xyz.map

   For a successful search, the end of the grep'ed output should
   look like this:
   kdebug:fopen(/some/paht/xyz.map, r) => 0x81cccd8

   If the search is not successful, look at the debugging output in
   more detail, checking which variable settings contribute to the
   path where a file is searched.

3. Make sure that xdvi finds the Type1 versions of your fonts. E.g.
   if your texmf tree is located in /usr/local/share/texmf,
   for a minimal LaTeX file like

   \documentclass{minimal}
   \begin{document}test\end{document}

   the command
   $ xdvi -debug 3968 ~/test.dvi 2>&1 | grep cmr10.pfb
 
   should contain a line at the bottom that looks similar to this:
   kdebug:search(cmr10.pfb) => /usr/local/share/texmf/fonts/type1/bluesky/cm/cmr10.pfb

   Check the settings of TEXMFMAIN, TEXMF and T1FONTS in your
   texmf.cnf file if this doesn't work.


See also kpathsea.dvi and TETEXDOC.dvi for more information on the
how kpathsea works.


Some common sources of problems:

- You have several texmf.cnf files on your system, and xdvi isn't
  using the one you expect. Use the following command to find out
  which:
  $ xdvi -debug 3968 ~/test.dvi 2>&1 | grep texmf.cnf | grep fopen

- The SELFAUTO... variables are used to define one of the TEXMF or
  XDVIINPUTS variables in texmf.cnf, but xdvi.bin hasn't been
  installed in a path that is compatible with SELFAUTO....
  For example, if your texmf tree is
     /usr/share/texmf/web2c/
  and the search path contains
     {$SELFAUTOLOC,$SELFAUTODIR,$SELFAUTOPARENT}{,{/share,}/texmf{-local,}/web2c}:
  then xdvi.bin should be contained 2 directories below
  /usr, e.g. in /usr/local/bin/xdvi.bin. ($SELFAUTOPARENT is
  a misnomer in that it actually denotes the grand-parent
  of the current directory, i.e. 2 levels up in the directory
  hierarchy).

  As a fix, either set XDVIINPUTS in your shell environment, or install
  xdvi.bin in its proper place.