path: root/upstream/debian-bookworm/man8/setfont.8

.TH SETFONT 8 "11 Feb 2001" "kbd"
.SH NAME
setfont \- load EGA/VGA console screen font
.SH SYNOPSIS
.B setfont
.RB [ -O
.IR font+umap.orig ]
.RB [ -o
.IR font.orig ]
.RB [ -om
.IR cmap.orig ]
.RB [ -ou
.IR umap.orig ]
.RB [ -\c
.IR N ]
.RI [ "font.new ...\&" ]
.RB [ -m
.IR cmap ]
.RB [ -u
.IR umap ]
.RB [ -C
.IR console ]
.RB [ -h\c
.IR H ]
.RB [ -f ]
.RB [ -v ]
.RB [ -V ]
.SH DESCRIPTION
The
.B setfont
command reads a font from the file
.I font.new
and loads it into the EGA/VGA character generator,
and optionally outputs the previous font.
It can also load various mapping tables
and output the previous versions.
.LP
If no args are given (or only the option
.RI \- N
for some number
.IR N ),
then a default
.RI (8x N )
font is loaded (see below).
One may give several small fonts, all containing
a Unicode table, and
.B setfont
will combine them and load the union.
Typical use:
.TP
.B setfont
Load a default font.
.TP
.B "setfont drdos8x16"
Load a given font (here the 448-glyph drdos font).
.TP
.B "setfont cybercafe -u cybercafe"
Load a given font that does not have a Unicode map
and provide one explicitly.
.TP
.B "setfont LatArCyrHeb-19 -m 8859-2"
Load a given font (here a 512-glyph font combining several
character sets) and indicate that one's local character set
is ISO 8859-2.
.LP
Note: if a font has more than 256 glyphs, only 8 out of 16 colors
can be used simultaneously. It can make console perception worse
(loss of intensity and even some colors).

.SH "FONT FORMATS"
The standard Linux font format is the PSF font.
It has a header describing font properties like character size,
followed by the glyph bitmaps, optionally followed by a Unicode mapping
table giving the Unicode value for each glyph.
Several other (obsolete) font formats are recognized.
If the input file has code page format (probably with suffix .cp),
containing three fonts with sizes e.g. 8x8, 8x14 and 8x16, then one of
the options \-8 or \-14 or \-16 must be used to select one.
Raw font files are binary files of size
.RI 256* N
bytes, containing bit images for each of 256 characters,
one byte per scan line, and
.I N
bytes per character (0 <
.I N
<= 32).
Most fonts have a width of 8 bits, but with the framebuffer device (fb)
other widths can be used.

.SH "FONT HEIGHT"
The program
.B setfont
has no built-in knowledge of VGA video modes, but just asks
the kernel to load the character ROM of the video card with
certain bitmaps. However, since Linux 1.3.1 the kernel knows
enough about EGA/VGA video modes to select a different line
distance. The default character height will be the number
.I N
inferred from the font or specified by option. However, the
user can specify a different character height
.I H
using the
.I "\-h"
option.

.SH "CONSOLE MAPS"
Several mappings are involved in the path from user program
output to console display. If the console is in utf8 mode (see
.BR unicode_start (1))
then the kernel expects that user program output is coded as UTF-8 (see
.BR utf-8 (7)),
and converts that to Unicode (ucs2).
Otherwise, a translation table is used from the 8-bit program output
to 16-bit Unicode values. Such a translation table is called a
.IR "Unicode console map" .
There are four of them: three built into the kernel, the fourth
settable using the
.I "\-m"
option of
.BR setfont .
An escape sequence chooses between these four tables; after loading a
.IR cmap ,
.B setfont
will output the escape sequence Esc ( K that makes it the active translation.
.LP
Suitable arguments for the
.I "\-m"
option are for example
.IR 8859-1 ,
.IR 8859-2 ", ...,"
.IR 8859-15 ,
.IR cp437 ", ...,"
.IR cp1250 .
.LP
Given the Unicode value of the symbol to be displayed, the kernel
finds the right glyph in the font using the Unicode mapping info
of the font and displays it.
.LP
Old fonts do not have Unicode mapping info, and in order to handle
them there are direct-to-font maps (also loaded using
.IR "\-m" )
that give a correspondence between user bytes and font positions.
The most common correspondence is the one given in the file
.I trivial
(where user byte values are used directly as font positions).
Other correspondences are sometimes preferable since the
PC video hardware expects line drawing characters in certain
font positions.
.LP
Giving a
.I "\-m none"
argument inhibits the loading and activation of a mapping table.
The previous console map can be saved to a file using the
.I "\-om file"
option.
These options of setfont render
.BR mapscrn (8)
obsolete. (However, it may be useful to read that man page.)

.SH "UNICODE FONT MAPS"
The correspondence between the glyphs in the font and
Unicode values is described by a Unicode mapping table.
Many fonts have a Unicode mapping table included in
the font file, and an explicit table can be indicated using
the
.I "\-u"
option. The program
.B setfont
will load such a Unicode mapping table, unless a
.I "\-u none"
argument is given. The previous Unicode mapping table
will be saved as part of the saved font file when the \-O
option is used. It can be saved to a separate file using the
.I "\-ou file"
option.
These options of setfont render
.BR loadunimap (8)
obsolete.
.LP
The Unicode mapping table should assign some glyph to
the `missing character' value U+fffd, otherwise missing
characters are not translated, giving a usually very confusing
result.

Usually no mapping table is needed, and a Unicode mapping table
is already contained in the font (sometimes this is indicated
by the .psfu extension), so that most users need not worry
about the precise meaning and functioning of these mapping tables.

One may add a Unicode mapping table to a psf font using
.BR psfaddtable (1).

.SH OPTIONS
.TP
.BI "\-h " H
Override font height.
.TP
.B \-d
Doubles the size of the font, by replicating all of its pixels
vertically and horizontally.  This is suitable for high pixel density
(e.g. "4k") displays on which the standard fonts are too small to be
easily legible.  Due to kernel limitations, this is suitable only for
16x16 or smaller fonts.
.TP
.BI "\-m " file
Load console map or Unicode console map from
.IR file .
.TP
.BI "\-o " file
Save previous font in
.IR file .
.TP
.BI "\-O " file
Save previous font and Unicode map in
.IR file .
.TP
.BI "\-om " file
Store console map in
.IR file .
.TP
.BI "\-ou " file
Save previous Unicode map in
.IR file .
.TP
.BI "\-u " file
Load Unicode table describing the font from
.IR file .
.TP
.BI "\-C " console
Set the font for the indicated console. (May require root permissions.)
.TP
.B \-f
Force-load unicode map: Setfont`issues the system call to load the unicode
map even if the specified map is empty.  This may be useful in unusual cases.
.TP
.B \-v
Be verbose.
.TP
.B \-V
Print version and exit.

.SH NOTE
PC video hardware allows one to use the "intensity" bit
either to indicate brightness, or to address 512 (instead of 256)
glyphs in the font. So, if the font has more than 256 glyphs,
the console will be reduced to 8 (instead of 16) colors.

.SH FILES
.TP
.I /usr/share/consolefonts
The default font directory.
.LP
.TP
.I /usr/share/unimaps
The default directory for Unicode maps.
.LP
.TP
.I /usr/share/consoletrans
The default directory for screen mappings.
.LP
The default font is a file
.I default
(or
.IR default8x N
if the \-N option was given for some number N)
perhaps with suitable extension (like .psf).
.SH "SEE ALSO"
.BR psfaddtable (1),
.BR unicode_start (1),
.BR loadunimap (8),
.BR utf-8 (7),
.BR mapscrn (8)
.\" .SH "AUTHORS"
.\" Eugene G. Crosser (crosser@pccross.msk.su)
.\" .br
.\" Andries E. Brouwer (aeb@cwi.nl)