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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.

       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 will be 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 will cause no font to be
	      mounted on the corresponding font position.

       hor n  The horizontal resolution is n machine units.

       paperheight 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 prede-
	      fined 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  ver-
	      tical 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
	      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 pointsizes.	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  will  be	associated with styles
	      S1...Sm.

       tcommand
	      This means that the postprocessor can handle the t and u	output
	      commands.

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

       use_charnames_in_special
	      This command indicates that troff should encode named characters
	      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  key-
       words  (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 com-
       pletely ignored: spare1, spare2, biggestfont.

   Font file format
       A font file has two sections.  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]
	      Characters  lig1,  lig2, ..., lign are ligatures; possible liga-
	      tures 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.
	      The normal width of a space is n.

       special
	      The  font  is  special;  this  means  that  when	a character is
	      requested that is not present in the current font,  it  will  be
	      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
       character.  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 character: if name is a single character 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 char-
       acter \[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 character is  unnamed;  such  characters
       can only be used by means of the \N escape sequence in troff.

       Groff supports eight-bit characters; however some utilities have diffi-
       culties with eight-bit characters.  For this reason, there is a conven-
       tion  that  the	name charn is equivalent to the single character whose
       code is n.  For example, char163 would be equivalent to	the  character
       with code 163 which is the pounds sterling sign in ISO Latin-1.

       The type field gives the character type:

       1      means the character has a descender, for example, p;

       2      means the character has an ascender, for example, b;

       3      means  the  character  has both an ascender and a descender, for
	      example, (.

       The code field gives the code which the postprocessor uses to print the
       character.  The character 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 will be interpreted as octal; if it starts with 0x
       or 0X it will be 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 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 sub-
       fields 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 character.  The height sub-
       field gives the height of the character (upwards  is  positive);  if  a
       character 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  character, that is, the distance below the lowest point
       below the baseline to which the character extends (downwards  is  posi-
       tive);  if  a  character  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 character when it is immediately to be  followed  by  a
       character from a roman font.  The left-italic-correction subfield gives
       the amount of space that should be added before the character  when  it
       is  immediately	to  be preceded by a character from a roman font.  The
       subscript-correction gives the amount of space  that  should  be  added
       after  a character 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  character  men-
       tioned 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 character c1 appears  next	to  character  c2  the
       space between them should be increased by n.  Most entries in kernpairs
       section will have a negative value for n.

FILES

       /usr/share/groff_font/devname/DESC
	      Device description file for device name.

       /usr/share/groff_font/devname/F
	      Font file for font F of device name.

SEE ALSO

       groff_out(5), troff(1).

Groff Version 1.19		  1 May 2003			 GROFF_FONT(5)

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