.TH FACE 7
.SH NAME
face \- face files
.SH DESCRIPTION
The directories
.B /usr/$user/lib/face
and
.B /lib/face
contain a hierarchy of images of people.
In those directories are subdirectories named by the sizes of
the corresponding image files:
.B 48x48x1
(48 by 48 pixels, one bit per pixel);
.B 48x48x2
(48 by 48 pixels, two (grey) bits per pixel);
.B 48x48x4
(48 by 48 pixels, four (grey) bits per pixel);
.B 48x48x8
(48 by 48 pixels, eight (color-mapped) bits per pixel);
.B 512x512x8
(512 by 512 pixels, eight (color-mapped) bits per pixel);
.B 512x512x24
(512 by 512 pixels, twenty-four bits per pixel (3 times 8 bits
per color)).
The large files serve no special purpose; they are stored
as images
(see
.IR image (7)).
The small files are the `icons'  displayed by
.B faces
and
.B seemail
(see Plan 9's
\fIfaces\fR(1));
for depths less than 4, their format is special.
.PP
One- and two-bit deep icons are stored as text, one line of the file to one scan line
of display.
Each line is divided into 8-bit, 16-bit, or 32-bit big-endian words,
stored as a list of comma-separated hexadecimal C constants,
such as:
.IP
.EX
0x9200, 0x1bb0, 0x003e,
.EE
.PP
This odd format is historical and the programs that read it
are somewhat forgiving about blanks and the need for commas.
.PP
The files
.BR  lib/face/*/.dict
hold a correspondence between users at machines
and face files.
The format is
.IP
.EX
.I machine\fB/\fPuser directory\fB/\fPfile\fB.\fPver
.EE
.PP
The
.I machine
is the domain name of the machine sending the message,
and
.I user
the name of the user sending it.
The
.I directory
is a further subdirectory of (say)
.BR /lib/face/48x48x1 ,
named by a single letter corresponding to the first character
of the user names.  The
.I file
is the name of the file, typically but not always the user name,
and
.I ver
is a number to distinguish different images, for example to
distinguish the image for Bill Gates from the image for Bill Joy,
both of which might otherwise be called
.BR b/bill .
For example, Bill Gates might be represented by the line
.IP
.EX
microsoft.com/bill b/bill.1
.EE
.PP
If multiple entries exist for a user in the various
.B .dict
files,
.I faces
chooses the highest pixel size less than or equal to that of the
display on which it is running.
.PP
Finally, or rather firstly, the file
.B /lib/face/.machinelist
contains a list of machine/domain pairs, one per line,
to map any of a set of machines to a single domain name to
be looked up in the
.B .dict
files.  The machine name may be a regular expression,
so for example the entry
.IP
.EX
\&.*research\e.bell-labs\e.com    astro
.EE
.PP
maps any of the machines in Bell Labs Research into the
shorthand name
.BR astro ,
which then appears as a domain name in the
.B .dict
files.
.SH "SEE ALSO"
.IR mail (1),
.IR tweak (1),
.IR image (7)