.TH UNIFONT 5 "2013 Sep 27"
.SH NAME
Unifont \- A bitmapped font with full Unicode Plane 0 (BMP) coverage
.SH SYNOPSIS
.br
.B unifont.hex
.SH DESCRIPTION
.B Unifont
is a bitmapped font with glyphs described in a plain text file, generically
referred to as
.B unifont.hex
herein.
This man page describes the format of three related files:
.B unifont.hex, masks.hex,
and
.B combining.txt.
All three of these files start with a Unicode code point as a hexadecimal
string, with code points appearing in ascending order.
.PP
A
.B unifont.hex
file consists of single-line entries for each Unicode code point.
Each line contains the code point, a colon (':') field separator,
and the glyph bitmap.
.B The glyphs in a unifont.hex format file must appear in ascending
.B Unicode code point order.
.PP
This file can be converted into a BDF font using the
.B hex2bdf (1)
program, and into a TrueType font using
.B fontforge (1)
(which is not part of this package).
The BDF font can also be converted into a PCF font using
.B bdftopcf (1)
(which is also not part of this package).
.PP
.B The first field
.RS
The first field is the Unicode code point in hexadecimal, ranging from
"0000" through "FFFF", inclusive.  This corresponds to the Unicode
code points U+0000 through U+FFFF, respectively.
.RE
.PP
.B The second field
.RS
The second field is the glyph's bitmap string.  This is a series of
hexadecimal digits.  Currently Unifont encodes two glyph sizes:
8 pixels wide by 16 pixels tall (single-width), and
16 pixels wide by 16 pixels tall (double-width).
.LP
As each hexadecimal digit can encode four bits, one pixel row of a glyph
is either two hexadecimal digits long (single-width) or four hexadecimal
digits long (double-width).  The glyphs are 16 pixels tall, so
a single-width glyph is (2)(16) = 32 hexadecimal digits long and
a double-width glyph is (4)(16) = 64 hexadecimal digits long.
.RE
.PP
Previous versions of this package supplied a file named
.B masks.hex.
This file followed the same format as
.B unifont.hex
with a first field that was a Unicode code point in hexadecimal,
followed by a colon (':') field separator,
followed by a second field that was a hexadecimal string representing
a glyph bitmap.  Code points were in ascending order.  The glyph bitmaps
were bitmaps that would be exclusive-ored with the glyph in
.B unifont.hex
that had the same code point.
The original
.B unifont.hex
contained combining circles as depicted in
.I The Unicode Standard.
When Paul Hardy got combining characters to display properly in the
TrueType version, it became desirable to remove these combining circles
for proper display with
.B unifont.ttf.
The program
.B uniunmask (1)
will read such a
.B masks.hex
file, read a
.B unifont.hex
format file, and apply the exclusive-or masks in
.B masks.hex
to
.B unifont.hex.
The output is another file in
.B unifont.hex
format with the masked-off bits (i.e., combining circles) removed.
.PP
Because the operation is an exclusive-or,
.B masks.hex
could also be used to turn on pixels in selective glyphs, for exmaple
to add combining circles to selective glyphs that do not show them.
However, the program
.B unigencircles (1)
can do this without a separate
.B masks.hex
file.  Thus
.B masks.hex
is no longer supplied with this package.
.B uniunmask (1)
remains part of this distribution in case someone might find creating a custom
.B masks.hex
file useful for another purpose.
.PP
The TrueType version of the font,
.B unifont.ttf,
and the
.B unigencircles (1)
utility both read a file
.B combining.txt.
This file appears in the directory
.B font/ttfsrc.
The
.B combining.txt
file is a list of code points as hexadecimal strings, one per line in
ascending order, of Unicode code points that show combining circles in
.I The Unicode Standard.
Any glyph with its code point listed in
.B combining.txt
will have zero width in
.B unifont.ttf.
.SH UTILITIES
Roman Czyborra, the font's creator, originally wrote two Perl scripts
as utilities:
.B bdfimplode (1)
and
.B hexdraw (1).
.PP
The
.B bdfimplode (1)
Perl script reads in a font in BDF format and generates a font output in
.B unifont.hex
format.
.PP
The
.B hexdraw (1)
Perl script might appear somewhat magical.  It can read a file in
.B unifont.hex
format and generate a text file with each glyph appearing
as a grid of characters in an 8 by 16 or 16 by 16 grid:
a '-' character indicates a corresponding white pixel, and
a '#' character indicates a corresponding black pixel.  These pixel grids
are indented.  The first line shows the code point for a glyph, followed
by a colon (':').  This text file can then be modified with any text
editor.  The magical part about
.B hexdraw (1)
is that it will read in
this text file, detect that it is in this converted format, and produce
as output a second file in Unifont's .hex format.  Thus
.B hexdraw (1)
automagically provides round-trip coverage between an original font file in
.B unifont.hex
format and an intermediate text graphics format for editing.
.PP
Utilities introduced after those first two convert a file in
.B unifont.hex
format to and from bitmapped
graphics (".bmp") files.  The
.B unihex2bmp (1)
program converts a file in
.B unifont.hex
format into a .bmp format file,
for editing with a graphics editor.  The
.B unibmp2hex (1)
program performs the reverse conversion, from a bitmapped graphics format
back to a file in
.B unifont.hex
format.
.PP
.B hexdraw (1), unihex2bmp (1),
and
.B unibmp2hex (1)
are the central programs that handle conversion of a
.B unifont.hex
file to and from two-dimensional glyph representations for visual editing.
See the
.B TUTORIAL
file included in the source pakcage for more information on these and
other utilities to customize
.B unifont.hex
format files.  Also consult the man pages for the utilities listed below.
.SH FILES
The following files are part of the Unifont source distribution:
.TP 15
.B font/plane00/*.hex
GNU Unifont font files
.TP 15
.B LICENSE
The Unifont license
.TP 15
.B README
Instructions on building Unifont
.TP 15
.B TUTORIAL
Tutorial on customizing Unifont
.SH SEE ALSO
.BR bdfimplode(1),
.BR hex2bdf(1),
.BR hex2sfd(1),
.BR hexbraille(1),
.BR hexdraw(1),
.BR hexkinya(1),
.BR hexmerge(1),
.BR johab2ucs2(1),
.BR unibdf2hex(1),
.BR unibmp2hex(1),
.BR unicoverage(1),
.BR unidup(1),
.BR unifont-viewer(1),
.BR unifontchojung(1),
.BR unifontksx(1),
.BR unifontpic(1),
.BR unigencircles(1),
.BR unigenwidth(1),
.BR unihex2bmp(1),
.BR unihex2png(1),
.BR unihexfill(1),
.BR unihexgen(1),
.BR unipagecount(1),
.BR unipng2hex(1)
.SH AUTHOR
The
.B unifont.hex
format was created by Roman Czyborra, who drew the original set of glyphs.
.SH LICENSE
.B unifont
is Copyright \(co 1998 Roman Czyborra, with portions Copyright \(co 2007-2013
Paul Hardy, Copyright \(co 2004-2013 Qianqian Fang, and others.
.PP
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
.SH BUGS
The format is very straihtforward and no real bugs exist.  However,
Unifont's original BDF font format does not support Unicode's combining
characters (accents, etc.); only the TrueType version of Unifont does.