plan9 man page for font

FONT(6) 							   Games Manual 							   FONT(6)

NAME
       font, subfont - external format for fonts and subfonts

SYNOPSIS
       #include <libg.h>

DESCRIPTION
       Fonts and subfonts are described in cachechars(2).

       External  fonts	are  described by a plain text file that can be read using rdfontfile.	The format of the file is a header followed by any
       number of subfont range specifications.	The header contains two numbers: the height and the ascent, both in pixels.   The  height  is  the
       inter-line  spacing  and  the ascent is the distance from the top of the line to the baseline.  These numbers are chosen to display consis-
       tently all the subfonts of the font.  A subfont range specification contains two or three numbers and a file name.   The  numbers  are  the
       inclusive  range  of  characters  covered by the subfont, with an optional starting position within the subfont, and the file name names an
       external file suitable for rdsubfontfile.  The minimum number of a covered range is mapped to  the  specified  starting	position  (default
       zero) of the corresponding subfont.  If the subfont file name does not begin with a slash, it is taken relative to the directory containing
       the font file.  Each field must be followed by some white space.  Each numeric field may be C-format decimal, octal, or hexadecimal.

       External subfonts are represented in a more rigid format that can be read and written using rdsubfontfile and  wrsubfontfile  (see  subfal-
       loc(2)).  The format for subfont files is: a bitmap containing character images, followed by a subfont header, followed by character infor-
       mation.	The bitmap has the format for external bitmap files described in bitmap(6).  The subfont header has 3 decimal strings: n,  height,
       and  ascent.   Each  number  is right-justified and blank padded in 11 characters, followed by a blank.	The character info consists of n+1
       6-byte entries, each giving the Fontchar x (2 bytes, low order byte first), top, bottom, left, and width.  The x field of the last Fontchar
       is used to calculate the bitmap width of the previous character; the other fields in the last Fontchar are irrelevant.

       Note  that  the	convention  of	using the character with value zero (NUL) to represent characters of zero width (see bitblt(2)) means that
       fonts should have, as their zeroth character, one with non-zero width.

FILES
       /lib/font/bit/*
	      font directories

SEE ALSO
       graphics(2), bitblt(2), cachechars(2), subfalloc(2)

																	   FONT(6)