GROFF_FONT(5)             OpenBSD Programmer's Manual            GROFF_FONT(5)



NAME
       groff_font - format of groff device and font description files

DESCRIPTION
       The groff font format is roughly a superset of the ditroff font format.
       The font files for device name are stored in a directory devname.
       There are two types of file: a device description file called DESC and
       for each font F a font file called F.  These are text files; unlike the
       ditroff font format, there is no associated binary format.

   DESC file format
       The DESC file can contain the following types of line as shown below.
       Later entries in the file override previous values.

       Empty lines are ignored.

       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 causes no font
              to be mounted on the corresponding font position.

       hor n  The horizontal resolution is n machine units.

       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 which 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.  Deprecated.  Use papersize instead.  This isn't
              used by troff itself but by output devices.

       pass_filenames
              Make troff tell the driver the source file name being processed.
              This is achieved by another tcommand: F filename.

       postpro program
              Use program as the postprocessor.

       prepro program
              Call program as a preprocessor.

       print program
              Use program as the 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 a 0.  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.

       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 output
              commands.

       unicode
              Indicate that the output device supports the complete Unicode
              repertoire.  Useful only for devices which 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 glyph
              widths.  Needed for the grohtml device.

       use_charnames_in_special
              This command indicates that troff should encode named glyphs
              inside special commands.

       vert n The vertical resolution is n machine units.

       The res, unitwidth, fonts, and sizes lines are compulsory.  Not all
       commands in the DESC file are used by troff itself; some of the
       keywords (or even additional ones) are used by postprocessors to store
       arbitrary information about the device.

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

   Font file format
       A font file has two sections; empty lines are ignored in both of them.

       The first section is a sequence of lines each containing a sequence of
       blank delimited words; the first word in the line is a key, and
       subsequent words give a value for that key.

       ligatures lig1 lig2 ... lign [0]
              Glyphs lig1, lig2, ..., lign are ligatures; possible ligatures
              are ff, fi, fl, ffi, and ffl.  For backwards compatibility, the
              list of ligatures may be terminated with a 0.  The list of
              ligatures may not extend over more than one line.

       name F The name of the font is F.

       slant n
              The glyphs of the font have a slant of n degrees.  (Positive
              means forward.)

       spacewidth n
              The normal width of a space is n.

       special
              The font is special; this means that when a glyph is requested
              that is not present in the current font, it is searched for in
              any special fonts that are mounted.

       Other commands are ignored by troff but may be used by postprocessors
       to store arbitrary information about the font in the font file.

       The first section can contain comments which start with the # character
       and extend to the end of a line.

       The second section contains one or two subsections.  It must contain a
       charset subsection and it may also contain a kernpairs subsection.
       These subsections can appear in any order.  Each subsection starts with
       a word on a line by itself.

       The word charset starts the charset subsection.  The charset line is
       followed by a sequence of lines.  Each line gives information for one
       glyph.  A line comprises a number of fields separated by blanks or
       tabs.  The format is

              name metrics type code [entity_name] [-- comment]

       name identifies the glyph: if name is a single glyph c then it
       corresponds to the groff input character c; if it is of the form \c
       where c is a single character, then it corresponds to the special
       character \[c]; otherwise it corresponds to the groff input character
       \[name].  If it is exactly two characters xx it can be entered as \(xx.
       Note that single-letter special characters can't be accessed as \c; the
       only exception is `\-' which is identical to `\[-]'.  The name --- is
       special and indicates that the glyph is unnamed; such glyphs can only
       be used by means of the \N escape sequence in troff.

       The type field gives the glyph type:

       1      means the glyph has a descender, for example, `p';

       2      means the glyph has an ascender, for example, `b';

       3      means the glyph has both an ascender and a descender, for
              example, `('.

       The code field gives the code which the postprocessor uses to print the
       glyph.  The glyph can also be input to groff using this code by means
       of the \N escape sequence.  The code can be any integer.  If it starts
       with a 0 it is interpreted as octal; if it starts with 0x or 0X it is
       intepreted as hexadecimal.  Note, however, that the \N escape sequence
       only accepts a decimal integer.

       The entity_name field gives an ASCII string identifying the glyph which
       the postprocessor uses to print that glyph.  This field is optional and
       is currently used by grops to build sub-encoding arrays for PS fonts
       containing more than 256 glyphs.  (It has also been used for grohtml's
       entity names but for efficiency reasons this data is now compiled
       directly into grohtml.)

       Anything on the line after the encoding field or `--' are ignored.

       The metrics field has the form (in one line; it is broken here for the
       sake of readability):

              width[,height[,depth[,italic-correction
              [,left-italic-correction[,subscript-correction]]]]]

       There must not be any spaces between these subfields.  Missing
       subfields are assumed to be 0.  The subfields are all decimal integers.
       Since there is no associated binary format, these values are not
       required to fit into a variable of type char as they are in ditroff.
       The width subfields gives the width of the glyph.  The height subfield
       gives the height of the glyph (upwards is positive); if a glyph does
       not extend above the baseline, it should be given a zero height, rather
       than a negative height.  The depth subfield gives the depth of the
       glyph, that is, the distance below the lowest point below the baseline
       to which the glyph extends (downwards is positive); if a glyph does not
       extend below above the baseline, it should be given a zero depth,
       rather than a negative depth.  The italic-correction subfield gives the
       amount of space that should be added after the glyph when it is
       immediately to be followed by a glyph from a roman font.  The left-
       italic-correction subfield gives the amount of space that should be
       added before the glyph when it is immediately to be preceded by a glyph
       from a roman font.  The subscript-correction gives the amount of space
       that should be added after a glyph before adding a subscript.  This
       should be less than the italic correction.

       A line in the charset section can also have the format

              name "

       This indicates that name is just another name for the glyph mentioned
       in the preceding line.

       The word kernpairs starts the kernpairs section.  This contains a
       sequence of lines of the form:

              c1 c2 n

       This means that when glyph c1 appears next to glyph c2 the space
       between them should be increased by n.  Most entries in kernpairs
       section have a negative value for n.

FILES
       /usr/local/share/groff/1.21/font/devname/DESC
              Device description file for device name.

       /usr/local/share/groff/1.21/font/devname/F
              Font file for font F of device name.

SEE ALSO
       groff_out(5), troff(1).



Groff Version 1.21             31 December 2010                  GROFF_FONT(5)
