compface, uncompface - compress and expand 48x48x1 face image files
compface [ infile [ outfile ] ] ...
uncompface [-X] [ infile [ outfile ] ] ...
compface is a filter for generating highly compressed representations
of 48x48x1 face image files. uncompface is an inverse filter which
performs an inverse transformation with no loss of data. The algorithm
used is highly tuned for its purpose and achieves better than a five to
one compression ratio on average. Arguments operate identically for
both programmes. The first argument, if present, causes input to be
taken from the named file instead of from standard input unless it is
the string ‘‘-’’. A second argument, if present, causes output to go
to the named file instead of to standard output unless it is the string
‘‘-’’. Subsequent pairs of arguments may be used to specify further
pairs of input and output files.
The input format for compface (and the output format for uncompface) is
48 lines each of 3 sixteen bit hexadecimal integers, comma terminated
in C initialiser style. The output format of compface (and the input
format for uncompface) is some number of lines made up of a space
followed by printable characters (in the range ‘‘!’’ to ‘‘~’’
inclusive). The first line contains 72 characters and following lines
contain 79 characters except that the last line may be short.
This version of compface has been patched to also be able to handle
normal XBM images. uncompface will produce XBM output only if the -X
switch is applied.
The amount of compression obtained varies between face image files but
the output of compface averages less than 200 characters. The average
number of output lines is three.
Exit status is normally 0. Possible errors include IO errors when
opening, reading or writing files, format errors in compface input
files and invalid arguments. Each results in an explanatory message on
standard error and an exit status of 1. A warning will be produced if
compface detects extra input data.
Nominating standard input as input more than once does not work.
25 January 1990