GROFF_FONT(5)		      File Formats 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 usu-
	      ally 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	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
	      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  sec-
	      tion,  they  either override the default mappings for those par-
	      ticular 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 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; 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 subse-
       quent 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 liga-
	      tures 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	corre-
       sponds  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  spe-
       cial  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	 exam-
	      ple, `('.

       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
       interpreted 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  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 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 immedi-
       ately  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 sec-
       tion have a negative value for n.

FILES
       /usr/share/groff/1.22.2/font/devname/DESC
	      Device description file for device name.

       /usr/share/groff/1.22.2/font/devname/F
	      Font file for font F of device name.

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



Groff Version 1.22.2		7 February 2013			 GROFF_FONT(5)