GROFF_FONT(5)                                                    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.

       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 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.

       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 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.

       name F The name of the font is F.

       slant n
              The characters 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 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 postprocessor uses to print the character.  This field is  optional
       and  has  been introduced so that the html device driver can encode its
       character set.  For example, the character `\[Po]'  is  represented  as
       `&pound;' in html 4.0.

       Anything  on the line after the encoding field resp. after `--' will be
       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 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 1.19.2            6 February 2006                  GROFF_FONT(5)
