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How to prepare DefaultTexFont.xml from the font file

This document describes the correspondence between the font files we use and data in DefaultTexFont.xml. The concrete approach (i.e. script files to regenerate XML data) hasn't been reproduced yet, although we were able to get nearly all the required information.

Data in our XML files is often inaccurate and/or seemingly generated from other TTF files than the files in the repository. Be prepared for that. When in doubt, refer to the original TFM files (they seem to correspond to our data better than the TFM files generated from our TTF files).

There are two helpful toolsets to work with our TTF files:

  1. To gather font metrics:

    $ ttf2tfm filename.ttf -v filename.vpl
$ tftopl filename.tfm > filename.tpl

    That will generate filename.tfm (binary) and filename.vpl, filename.tpl (text).

    ttf2tfm and tftopl are parts of the standard TeX distribution (at least TeX Live).

  2. It may be helpful to use the ttx utility to get some additional information about the font (e.g. mapping from characters to codes in the font file):

    $ ttx filename.ttf

    That will generate filename.ttx (XML).

For example, there's the following in DefaultTexFont.xml:

<Font name="cmmi10.ttf" id="0" space="0.0" xHeight="0.430555" skewChar="196" quad="1.000003">
    <Char code="65" width="0.750002" height="0.683332" >
        <Kern code="196" val="0.138893"/>
    </Char>
</Font>

To get these values from the cmmi10.tpl file, search for the following:

(FONTDIMEN
   (SLANT R 0.25)
   (SPACE R 0.0)
   (STRETCH R 0.0)
   (SHRINK R 0.0)
   (XHEIGHT R 0.430555)
   (QUAD R 1.000003)
   )

…

(CHARACTER C A
   (CHARWD R 0.750002)
   (CHARHT R 0.683332)
   (COMMENT
      (KRN O 177 R 0.138893)
      )
   )

Here, CHARWD corresponds to width, CHARHT corresponds to height, CHARDP corresponds to depth, and CHARIC corresponds to italic. Any of them could be omitted.

The kerning section can also be reconstructed from the *.tpl file.

How can we know that O 177 is the same as code="196"? To do that, first look into cmmi10.vpl file: there's the following entry:

(CHARACTER O 177 (comment dieresis)
   (CHARWD R 583)
   (CHARHT R 705)
   (CHARIC R 118)
   (MAP
      (SETCHAR O 151)
      )
   )

That means that O 177 is named dieresis. Then, open Adobe Glyph List and search for the dieresis name:

dieresis;00A8

It means that O 177 should be character 0xa8 or 168, not 196. The reason for that inconsistency is currently unknown.