.TH UNIHEXROTATE 1 "2019 Feb 23"
.SH NAME
unihexrotate \- rotate Unifont hex glyphs in quarter turn increments
.SH SYNOPSIS
\fBunihexrotate \fP[\-n \fIquarter-turns\fP] [\fIinput-font.hex\fP] > \fIoutput-font.hex\fP
.SH DESCRIPTION
.B unihexrotate
reads a GNU Unifont .hex format file named on the command line,
or from stdin if no filename is given.  If a number of quarter turns
is specified, it rotates each glyph clockwise by that number of
quarter turns, or counterclockwise if the number is negative.
The resulting modified .hex file is written to stdout.
The format of a .hex file is described in the \fBunifont\fP(5) man page.
.PP
If the number of quarter turns is not specified,
.B unihexrotate
will rotate each glyph by a default value of one quarter turn
(i.e., 90 degrees) clockwise.
.PP
.B unihexrotate
only supports Unifont .hex files with glyphs that are 8 columns
and 16 columns wide.  If an 8-column glyph is rotated, it is
first centered within a 16-column glyph so the rotation will be
performed on a 16-by-16 pixel glyph.  One additional use of
this program is that a glyph can be converted from 8\~columns
wide to 16\~columns wide by specifying a rotation of 0\~quarter turns.
.SH OPTIONS
.TP 6
.BR \-n
Specify an integer number of quarter turn clockwise rotations
to perform, typically as "\-n\~0" through "\-n\~3" (alternatively
as "\-n=0" through "\-n=3") for rotations of 0, 90, 180, or 270
degrees, respectively.  Negative values will perform
counterclockwise rotations by the specified number of
quarter turns.
.SH EXAMPLES
This example extracts the Mongolian glyphs in the
"unifont-base.hex" file (located in the "font/plane00" directory)
and pipes them to \fBunihexrotate\fP to rotate by the default
amount of one quarter turn clockwise (i.e., by 90 degrees).
The basic Mongolian glyphs are in the Unicode range U+1800 through U+18AF.
The original glyphs in "unifont-base.hex" are drawn for horizontal
rendering (as per the Unicode Standard).  The output rotated
glyphs are suitable for rendering Mongolian in its traditional
vertical form.  Because no filename is specified to \fBunihexrotate\fP
in this example, its input is taken from stdin.
.PP
.RS
grep "^18[0-A]" unifont-base.hex | \fBunihexrotate\fP > vertical.hex
.RE
.PP
The next example reverses the rotation performed above, by one
quarter turn counterclockwise.  In this example, the input filename
"vertical.hex" is specified.
.PP
.RS
\fBunihexrotate\fP \-n \-1 vertical.hex > horizontal.hex
.RE
.SH FILES
Unifont .hex format input and output files.
.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 unibmpbump(1),
.BR unicoverage(1),
.BR unidup(1),
.BR unifont(5),
.BR unifont-viewer(1),
.BR unifont1per(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
.B unihexrotate
was written by David Corbett.
.SH LICENSE
.B unihexrotate
is Copyright \(co 2019 David Corbett.
.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
No known bugs exist.