#! perl -slw
use strict;
use Data::Dump qw[ pp ];
use List::Util qw[ reduce sum ];
use GD;

#use constant {
#    WHITE => 16777215,
#    MinX => 10.318842, MaxX => 14.124424,
#    MinY => 21.097507, MaxY => 24.912207,
#};
#use constant {
    WHITE => 16777215,
    MinX => 0, MaxX => 1,
    MinY => 0, MaxY => 1,
};

use constant {
    SpanX => MaxX - MinX, SpanY => MaxY - MinY,
};

sub rgb2n{ unpack 'N', pack 'CCCC', 0, @_ }
sub n2rgb{ unpack 'xCCC', pack 'N', $_[0] }

our $POINTS ||= 300_000;
our $SCALER ||= 1000;
our $DELTA  ||= 20;

my @points = map [ MinX + rand( SpanX ), MinY + rand( SpanY ) ], 1 .. $POINTS;

## Normalise to our grid, scale by 1000 and integerise
my @scaled = map [
    int( ( $_->[ 0 ] - MinX ) * $SCALER ),
    int( ( $_->[ 1 ] - MinY ) * $SCALER ),
], @points;

my( $sizeX, $sizeY ) = ( int( SpanX * $SCALER ), int( SpanY * $SCALER ) );
my $img = GD::Image->new( $sizeX, $sizeY , 1 );
$img->filledRectangle( 0, 0, $sizeX, $sizeY, rgb2n( 255, 255, 255 ) );


for my $i ( 0 .. $#scaled ) {
    my $color = $img->getPixel( @{ $scaled[ $i ] } );
    $img->filledEllipse( @{ $scaled[ $i ] }, $DELTA, $DELTA, $i );
    $img->setPixel( @{ $scaled[ $i ] }, $color );
}

my %groups;
for my $i ( 0 .. $#scaled ) {
    my $color = $img->getPixel( @{ $scaled[ $i ] } );
    if( $color != WHITE ) {
        push @{ $groups{ $color } }, $i;
    }
    else {
        $color = $i;
    }
    $img->ellipse( @{ $scaled[ $i ] }, $DELTA, $DELTA, $i );
}

printf "Found %d groups containing a total of %d points\n",
    scalar keys( %groups), sum( map scalar @$_, values %groups );

open IMG, '>:raw', '694790all.png' or die $!;
print IMG $img->png;
close IMG;
system 1, '694790all.png';

undef $img;

open OUT, '>', '694790.groups' or die $!;
for my $key ( sort { $a <=> $b } keys %groups ) {
    print OUT "[ @{ $points[ $_ ] } ]" for $key, @{ $groups{ $key } };
    print OUT "------";
}
close OUT;

$img = GD::Image->new( $sizeX, $sizeY , 1 );
$img->filledRectangle( 0, 0, $sizeX, $sizeY, rgb2n( 255, 255, 255 ) );

for my $key ( sort { $a <=> $b } keys %groups ) {
    for my $point ( $scaled[ $key ], @scaled[ @{ $groups{ $key } } ]  ) {
        $img->setPixel( @{ $point }, $key );
        $img->ellipse( @{ $point }, $DELTA, $DELTA, $key );
    }
}

open IMG, '>:raw', '694790grouped.png' or die $!;
print IMG $img->png;
close IMG;
system 1, '694790grouped.png';