8.2.1 DESC File Format

The DESC file can contain the following types of line. Except for the charset keyword, which must comes last (if at all), the order of the lines is not important. Later entries in the file, however, override previous values.

charset

This line and everything following in the file are ignored. It is allowed for the sake of backwards compatibility.

family fam

The default font family is fam.

fonts n F1 F2 F3 … Fn

Fonts F1 … Fn are mounted in the font positions m+1, …, m+n where m is the number of styles. This command may extend over more than one line. A font name of 0 means no font is mounted on the corresponding font position.

hor n

The horizontal resolution is n machine units. All horizontal quantities are rounded to be multiples of this value.

image_generator string

Needed for grohtml only. It specifies the program to generate PNG images from POSTSCRIPT input. Under GNU/Linux this is usually gs but under other systems (notably cygwin) it might be set to another name.

paperlength n

The physical vertical dimension of the output medium in machine units. This isn’t used by troff itself but by output devices. Deprecated. Use papersize instead.

papersize string …

Select a paper size. Valid values for string are the ISO paper types A0-A7, B0-B7, C0-C7, D0-D7, DL, and the US paper types letter, legal, tabloid, ledger, statement, executive, com10, and monarch. Case is not significant for string if it holds predefined paper types. Alternatively, string can be a file name (e.g. /etc/papersize); if the file can be opened, groff reads the first line and tests for the above paper sizes. Finally, string can be a custom paper size in the format length,width (no spaces before and after the comma). Both length and width must have a unit appended; valid values are ‘i’ for inches, ‘C’ for centimeters, ‘p’ for points, and ‘P’ for picas. Example: 12c,235p. An argument that starts with a digit is always treated as a custom paper format. papersize sets both the vertical and horizontal dimension of the output medium.

More than one argument can be specified; groff scans from left to right and uses the first valid paper specification.

paperwidth n

The physical horizontal dimension of the output medium in machine units. This isn’t used by troff itself but by output devices. Deprecated. Use papersize instead.

pass_filenames

Tell gtroff to emit the name of the source file currently being processed. This is achieved by the intermediate output command ‘F’. Currently, this is only used by the grohtml output device.

postpro program

Call program as a postprocessor. For example, the line

postpro grodvi

in the file devdvi/DESC makes groff call grodvi if option -Tdvi is given (and -Z isn’t used).

prepro program

Call program as a preprocessor. Currently, this keyword is used by groff with option -Thtml or -Txhtml only.

print program

Use program as a spooler program for printing. If omitted, the -l and -L options of groff are ignored.

res n

There are n machine units per inch.

sizes s1 s2 … sn 0

This means that the device has fonts at s1, s2, … sn scaled points. The list of sizes must be terminated by 0 (this is digit zero). Each si can also be a range of sizes m-n. The list can extend over more than one line.

sizescale n

The scale factor for point sizes. By default this has a value of 1. One scaled point is equal to one point/n. The arguments to the unitwidth and sizes commands are given in scaled points. See Fractional Type Sizes, for more information.

styles S1 S2 … Sm

The first m font positions are associated with styles S1 … Sm.

tcommand

This means that the postprocessor can handle the ‘t’ and ‘u’ intermediate output commands.

unicode

Indicate that the output device supports the complete Unicode repertoire. Useful only for devices that produce character entities instead of glyphs.

If unicode is present, no charset section is required in the font description files since the Unicode handling built into groff is used. However, if there are entries in a charset section, they either override the default mappings for those particular characters or add new mappings (normally for composite characters).

This is used for -Tutf8, -Thtml, and -Txhtml.

unitwidth n

Quantities in the font files are given in machine units for fonts whose point size is n scaled points.

unscaled_charwidths

Make the font handling module always return unscaled character widths. Needed for the grohtml device.

use_charnames_in_special

This command indicates that gtroff should encode special characters inside special commands. Currently, this is only used by the grohtml output device. See Postprocessor Access.

vert n

The vertical resolution is n machine units. All vertical quantities are rounded to be multiples of this value.

The res, unitwidth, fonts, and sizes lines are mandatory. Other commands are ignored by gtroff but may be used by postprocessors to store arbitrary information about the device in the DESC file.

Here a list of obsolete keywords that are recognized by groff but completely ignored: spare1, spare2, biggestfont.