9.1 Charspace usage

Charspace makes no attempt to be intelligent about the side bearings it computes; it just follows the instructions in the CMI files.

The CMI files must be created by human hands, since the information they contain usually cannot be determined automatically. See the next section for the details on what CMI files contain.

We supply one CMI file, `common.cmi' (distributed in the `data' directory), which defines more-or-less typeface-independent definitions for most common characters. Charspace reads `common.cmi' before any of the CMI files you supply, so your definitions override its.

`common.cmi' can be used for all typefaces because its definitions are entirely symbolic; therefore, your CMI file must define actual values for the identifiers it uses. For example, `common.cmi' defines the right side bearing of `K' to be uc-min-sb; you yourself must define uc-min-sb.

You must also define side bearings for characters not in `common.cmi'. And you can redefine side bearings that are in `common.cmi', if you find its definitions unsuitable.

Once you have prepared a CMI file, you can run Charspace, e.g.:

charspace -verbose -encoding=enc-file fontname.dpi \ -output-file=out-fontname

where enc-file specifies the encoding, fontname the input font, dpi the resolution, and out-fontname the name of the output font.

With these options, Charspace will write files `out-fontname.tfm' and `out-fontname.dpigf'. You can then run TeX on `testfont.tex', telling TeX to use the font out-fontname. This produces a DVI file which you can print or preview as you usually do with TeX documents.

This will probably reveal problems in your CMI file, e.g., the spacing for some characters or character combinations will be poor. So you need to iterate.

However, if you are planning to eventually run your bitmap font through Limn (see section 10. Limn) and BZRto (see section 11. BZRto) to make an outline font, there's little point in excessively fine-tuning the spacing of the original bitmap font. The reason is that the generated outline font will inevitably rasterize differently than the original bitmaps, and the change in character shapes will almost certainly affect the spacing.