#!/usr/sww/bin/perl
########################################################################
##
## NAME:         center
##
## USAGE:        center <PPM_FILE>
##
## DESCRIPTION:  This is a perl script to search through an ASCII PPM (portable
##               pixel map) file describing the binary picture from an 
##               Eyesys videokeratograph and return the center.
##
## AUTHOR:       Dan Garcia  -  University of California at Berkeley
##               ddgarcia@cs.berkeley.edu
##
## DATE:         94-10-31
##
## REVISION:     1.0
##
##########################################################################

unless ($#ARGV >= 0) {        # are there any command line arguments?
    print "Usage: $0 PPM_FILE\n";
    print "       Read in a PPM (Portable Pixel Map) file describing\n";
    print "       the binary picture from an Eyesys videokeratograph\n";
    print "       and prints out the center\n";
    exit 1;
}

$headerfile = $ARGV[0];

open(HEADER, $headerfile) || die "$0 couldn't open PPM file $headerfile: $!\n";

@ppmFile = <HEADER>;

@firstRow = split(/  */,$ppmFile[4]);

## Due to the regular expression above, the first element in the row
## is NOT firstRow[0] but firstRow[1], thus the index difference

$xcent = (($firstRow[6] << 8) + $firstRow[5])/10.0;
$ycent = (($firstRow[8] << 8) + $firstRow[7])/10.0;

printf "%.1f %.1f\n", $xcent, $ycent;

## // c++ code from Eyesys people to recover center information
##
## // ---- input image ----
##
## if (fh = open(infile, O_RDONLY)) == -1) {
##    close(fh);
##    return(FAILURE);
## }
##
## n = 48;
## nbytes = 512 * n;
## for (j = 0 ; j < 480 ; j+= n) {
##    if ((bytesread = read(fh, big_buf[j], nbytes)) = -1) {
##        close(fh);
##        return(FAILURE);
##    }
## }
##
## close (fh);
##
## // ---- get center information ----
##
## c_x = (float) big_buf[0][4];
## c_x = c_x + (float) (big_buf[0][5] << 8);
## c_x = c_x / 10;
##
## c_y = (float) big_buf[0][6];
## c_y = c_y + (float) (big_buf[0][7] << 8);
## c_y = c_y / 10;
##