#!/usr/bin/perl -w
#nathan jahnke <njahnke@gmail.com>

use Image::Magick;
use Statistics::Descriptive;

$source = '/Volumes/l/h';
$out = '/Volumes/l/o';

for ($source, $out) {
	$_ = shift @ARGV or die "Usage: $0 sourcedir destdir";
}

$ext='png';

#info about the original video
$fps=30;

#info about the destination video
$destwidth=512;
$destheight=384;

#number of seconds to average crop values
$interval=2;

#default fuzz% value
#started with 10 but that seemed to get a lot of false positives with bloom from the screen in bright areas
$defaultfuzz = 30;
$fuzz = $defaultfuzz;

#$width and $height are set automatically from first image below
# $width=640;#expected width of input
# $height=480;#expected height of input

#you can override these here, otherwise they are set automatically below
# $topmax = 0;
# $leftmax = 0;
# $rightmax = 0;
# $bottommax = 0;

my $image = Image::Magick->new(magick=>'png');

opendir(PIX,$source);
@pix = grep { /\.${ext}$/ } readdir(PIX);
closedir(PIX);

$count=0;
for (@pix) {
	#next if !/\.${ext}$/;
	print $_, "\n";
	if ($count == 0) {
		#[re]initialize stats objects
		$lefto = Statistics::Descriptive::Full->new();
		$righto = Statistics::Descriptive::Full->new();
		$topo = Statistics::Descriptive::Full->new();
		$bottomo = Statistics::Descriptive::Full->new();
	}
	$count++;
	
	open( my $frame, "${source}/${_}" ) or die $!;
        my $framedata = do { local( $/ ) ; <$frame> } ;
        close($frame);
	$image->BlobToImage($framedata);
	
	if (!($width && $height)) {
		($width, $height) = $image->Get('width','height');
		#set crop maximums if not already set above - default is half the image width/height since the screen is unlikely to not take up at least most of the frame
		$topmax = ($height / 2) if !defined $topmax;
		$leftmax = ($width / 2) if !defined $leftmax;
		$rightmax = ($width / 2) if !defined $rightmax;
		$bottommax = ($height / 2) if !defined $bottommax;
	}
	
	$image->Trim(fuzz => $fuzz.'%');
	my $page = $image->Get('page');
	my ($left, $top) = ($page =~ m/^\d+x\d+\+(\d+)\+(\d+)$/);
	my ($currentwidth, $currentheight) = $image->Get('width','height');
	my ($right, $bottom) = ( (640-$currentwidth), (480-$currentheight) );
	if (!($right && $left && $top && $bottom)) { #autocrop failed to crop something
		if ($fuzz < 100) { #try again with higher "fuzz" value
			$fuzz+=2; #could increment by just one but it's god awful slow (22 march 2009)
			$count--;
			@$image = (); #redo doesn't go through continue block
			redo;
		} else { #or give up, if we've already tried up to 100% fuzz and still can't crop
			push(@imagebuffer,$_,$framedata);
			next; #screw this frame
		}
	} elsif ( #do any of the trim values exceed our maximums?
		($top > $topmax)
		||
		($left > $leftmax)
		||
		($right > $rightmax)
		||
		($bottom > $bottommax)
	) { #setting fuzz higher won't help; bail on this frame
		push(@imagebuffer,$_,$framedata);
		next; #screw this frame
	}
	
	push(@imagebuffer,$_,$framedata);
	print "   ${top}\n";
	print "${left}    ${right}\n";
	print "   ${bottom}\n";
	print "\n";
	for my $stat (
		[$lefto,	$left	],
		[$righto,	$right	],
		[$topo,		$top	],
		[$bottomo,	$bottom	],
	) {
		$$stat[0]->add_data($$stat[1]);
		#print "\n".$topo->count()."\n";
	}

 	if (($count >= ($interval*$fps)) || ($_ eq $pix[-1])) { #is this the last frame?
		$count=0;

		print "\n\nMean\n";
		print "   ".sprintf("%.0f",$topo->mean)."\n";
		print sprintf("%.0f",$lefto->mean)."    ".sprintf("%.0f",$righto->mean)."\n";
		print "   ".sprintf("%.0f",$bottomo->mean)."\n";
		print "\n\n\n";
		
		my $leftmean = sprintf("%.0f",$lefto->mean);
		my $topmean  = sprintf("%.0f",$topo->mean);
		my $newwidth  = ($width - sprintf("%.0f",$righto->mean));
		my $newheight = ($height - sprintf("%.0f",$bottomo->mean));
		while (my $filename = shift @imagebuffer) {
			my $imagedata = shift @imagebuffer or die $!;
			@$image = ();
			$image->Read(blob => $imagedata);
			$image->Crop(geometry => #argh, i want my avisynth
						     $newwidth
						.'x'.$newheight
						.'!' #ignore aspect ratio
						.'+'.$leftmean
						.'+'.$topmean
					);
			$image->Resize(geometry => $destwidth.'x'.$destheight.'!', filter=> 'Lanczos');
			$image->Write("${out}/${filename}");
		}
		
 	}
} continue {
	$fuzz=$defaultfuzz;
	@$image = ();
}

exit 0;