# $s is our segmented image

use integer;

my ( $w, $h ) = $s-> dims;

my $str = ${ $s-> byte-> get_dataref };

my @b = map {
    [ [ $w, 0 ], [ $h, 0 ] ]
} 1 .. $s-> max;

while ( $str =~ /[^\x00]/g ) {
    my $i = pos( $str ) - 1;
    my $x = $i % $w;
    my $y = $i / $w;
    my $c = ord( $& ) - 1;
    $b[ $c ][ 0 ][ 0 ] = $x if $x < $b[ $c ][ 0 ][ 0 ];
    $b[ $c ][ 0 ][ 1 ] = $x if $x > $b[ $c ][ 0 ][ 1 ];
    $b[ $c ][ 1 ][ 0 ] = $y if $y < $b[ $c ][ 1 ][ 0 ];
    $b[ $c ][ 1 ][ 1 ] = $y if $y > $b[ $c ][ 1 ][ 1 ];
}