This program converts a bitmap font file to ``something else''.  For
example, a representation as plain text; a TFM file; or a GF file.

Plain text is useful if you want to see exactly which pixels are on and
off in the bitmaps.

Having a TFM file is necessary to use the font with TeX.  No side
bearings, kerning, or ligature information is added to the TFM file, so
it is only useful for proofing, but that's better than nothing.

You can also select a range of characters, omit individual characters,
and change the character codes.  With these options, you want to output
another bitmap file; hence, the last option.

You can also filter the bitmaps through a simple averaging filter.  This
is useful as a preliminary cleanup of scanned images.  The filtering
removes a fair amount of the noise, but it also fills in and/or rounds
off sharp corners.
