9 contain a hierarchy of images of people.
10 In those directories are subdirectories named by the sizes of
11 the corresponding image files:
13 (48 by 48 pixels, one bit per pixel);
15 (48 by 48 pixels, two (grey) bits per pixel);
17 (48 by 48 pixels, four (grey) bits per pixel);
19 (48 by 48 pixels, eight (color-mapped) bits per pixel);
21 (512 by 512 pixels, eight (color-mapped) bits per pixel);
23 (512 by 512 pixels, twenty-four bits per pixel (3 times 8 bits
25 The large files serve no special purpose; they are stored
29 The small files are the `icons' displayed by
35 for depths less than 4, their format is special.
37 One- and two-bit deep icons are stored as text, one line of the file to one scan line
39 Each line is divided into 8-bit, 16-bit, or 32-bit big-endian words,
40 stored as a list of comma-separated hexadecimal C constants,
44 0x9200, 0x1bb0, 0x003e,
47 This odd format is historical and the programs that read it
48 are somewhat forgiving about blanks and the need for commas.
52 hold a correspondence between users at machines
57 .I machine\fB/\fPuser directory\fB/\fPfile\fB.\fPver
62 is the domain name of the machine sending the message,
65 the name of the user sending it.
68 is a further subdirectory of (say)
69 .BR /lib/face/48x48x1 ,
70 named by a single letter corresponding to the first character
71 of the user names. The
73 is the name of the file, typically but not always the user name,
76 is a number to distinguish different images, for example to
77 distinguish the image for Bill Gates from the image for Bill Joy,
78 both of which might otherwise be called
80 For example, Bill Gates might be represented by the line
83 microsoft.com/bill b/bill.1
86 If multiple entries exist for a user in the various
90 chooses the highest pixel size less than or equal to that of the
91 display on which it is running.
93 Finally, or rather firstly, the file
94 .B /lib/face/.machinelist
95 contains a list of machine/domain pairs, one per line,
96 to map any of a set of machines to a single domain name to
99 files. The machine name may be a regular expression,
100 so for example the entry
103 \&.*research\e.bell-labs\e.com astro
106 maps any of the machines in Bell Labs Research into the
109 which then appears as a domain name in the