Provided by: groff_1.18.1.1-20_i386 bug

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; currently, only grops
              uses it.

       paperwidth n
              The physical  horizontal  dimension  of  the  output  medium  in
              machine  units.   This isn’t used by troff.  Currently, only the
              grolbp output device uses it.

       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.

       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.

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

       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.  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
              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 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
       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 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
       difficulties with eight-bit characters.  For this reason,  there  is  a
       convention  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
       ‘£’ 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
       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  character.   The  height
       subfield  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
       positive); 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
       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  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/1.18.1/font/devname/DESC
              Device description file for device name.

       /usr/share/groff/1.18.1/font/devname/F
              Font file for font F of device name.

SEE ALSO

       groff_out(5), troff(1).