#!/usr/bin/perl -w
# $Id$
# Convert Photoshop curves files (.acv) to GIMP curves
# Assume 5 curves/channels per file
# Outputs to stdout
# ajr, 2005-06-30

$DEBUG = 0;

my $file=$ARGV[0];

open(FILE, "<$file") or die("Couldn't open $file for reading: $!\n");

# read number of curves
read(FILE, $header, 4) == 4 or die "Short read: $!\n";
@header=unpack("n n", $header);
$curves=$header[1];
print STDERR "$curves curves in $file\n" if $DEBUG;
warn("More than 5 curves, output may be invalid!\n") if ($curves > 5);

print "# GIMP Curves File\n";
for ($i = 1; $i <= $curves; $i++) {
	read(FILE, $points, 2) == 2 or die "Short read: $!\n";
	@points = unpack("n", $points);
	$points = $points[0];
	print STDERR "Curve #$i: $points points\n" if $DEBUG;
	warn("$points in curve $i, some points will be ignored") if ($points > 17);
	for ($p = 1; $p < $points; $p++) {
		read(FILE, $pair, 4) == 4 or die("Short read: $!\n");
		@pair=unpack("n n", $pair);
		# ACV pairs are in y,x order so swap:
		print "$pair[1] $pair[0] ";
	}
	# pad with null pairs up to 16 points
	for ($p = 1; $p <= (17 - $points); $p++) {
		print "-1 -1 ";
	}
	# final point
	read(FILE, $pair, 4) == 4 or die("Short read: $!\n");
	@pair=unpack("n n", $pair);
	print "$pair[1] $pair[0]\n";
}

warn("Unread data left in file\n") if (!eof(FILE));

close(FILE);