#! perl -slw
use strict;
use Data::Dumper;
use List::Util qw[ reduce sum max min ];
use GD;

sub check { 
	my $img = GD::Image->new( shift() );
	my( $iMin, $iMax, %freq ) = ( 0, 0 );
	my( $xMax, $yMax ) = $img->getBounds;
	for my $y ( 0 .. $yMax - 1 ) {
		for my $x ( 0 .. $xMax - 1 ) {
			my $i = reduce{ ($a<<8) + $b;} $img->rgb( $img->getPixel( $x, $y ) );
			$freq{ $i  }++;
			$iMin = $iMin < $i ? $iMin : $i;
			$iMax = $iMax > $i ? $iMax : $i;
		}
	}
	my $count = $xMax * $yMax;
	my $ex = 16777216 / ( $iMax - $iMin );
	
	my %norm;
	while( my( $i, $f ) = each %freq ) {
		$norm{ ( ( $i - $iMin ) * $ex ) / 16777216 } = $f / $count;
	}
	return 100 * sum map{ $_ * $norm{ $_ } } keys %norm;
}

my %sums = map{ check( $_ ), $_ } map glob, @ARGV;

printf "%32s : %7.5f\n", $sums{ $_ }, $_ for sort { $a <=> $b } keys %sums;

__END__