#!/usr/bin/perl

use Image::Magick;

$xsize = 400;
$ysize = 400;

$image = Image::Magick->new('size'=>"${xsize}x${ysize}");
$image->ReadImage('xc:white');

$cabase = 1000;
$clbase = 35;

foreach $x (1..$xsize){
	$mlevel = int( ($x/$xsize) * 110 );
	$mlevel = 1 if ($mlevel < 1);

	foreach $y (1..$ysize){
		$mdef = int( ($y/$ysize) * 3000 );

		#100 * AR / (AR + DR) * 2 * alvl / (alvl + dlvl)
		$cth = 100 * ( $cabase / ($cabase + $mdef) ) * 2 * ( $clbase / ($clbase + $mlevel) );

		# caps
		$cth = 5 if ($cth < 5);
		$cth = 95 if ($cth > 95);

		# reference band
		$cth = 0 if ($cth >45 && $cth < 55);

		# add marks at approx every 30th level and 1000th def point
		$cth = 0 if ($mdef % 1000 < 20);
		$cth = 0 if ($mlevel % 30 < 2);

		# make the graph more readable by dividing it up in to 10% chunks
		$cth = 0 unless ($cth % 10);

		$scth = int(($cth / 100) * 255);
		$hcth = sprintf("%lx",$scth);
		$r = $image->Set("pixel[" . ($x - 1) . "," . ($y - 1) . "]" => "#${hcth}0000");
		warn "$r" if $r;
	}
}
$r = $image->Write('doi.gif');
warn "$r" if $r;