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.
       Unlike the ditroff font format, there is no associated binary 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; there is no
       associated binary format.

   DESC file format
       The DESC file can contain the following types of line:

       res n  There are n machine units per inch.

       hor n  The horizontal resolution is n machine units.

       vert n The vertical resolution is n machine units.

       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.

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

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

       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.

       styles S1 S2...Sm
              The first m font positions will be associated with styles
              S1...Sm.

       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.

       family fam
              The default font family is fam.

       charset
              This line and everything following in the file are ignored.  It
              is allowed for the sake of backwards compatibility.

       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.

   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.

       name F The name of the font is F.

       spacewidth n
              The normal width of a space is n.

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

       ligatures lig1 lig2...lign [0]
              Characters lig1, lig2,...,lign are ligatures; possible ligatures
              are ff, fi, fl 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.

       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 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 groff input
       character \c; otherwise it corresponds to the groff input character
       \[name] (if it is exactly two characters xx it can be entered as \(xx.)
       Groff supports eight bit characters; however some utilities has
       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 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.

       The type field gives the character type:

       1      means the character has an 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.

       Anything on the line after the code field will be ignored.

       The metrics field has the form:


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

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

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



Groff Version 1.15                                                9 April 2000
