#!/usr/bin/perl

use strict;
use warnings;
use Gtk2 -init;
use Gtk2::Ex::Dialogs;
use Gtk2::Gdk::Keysyms;
use Glib ':constants';
use Goo::Canvas;

# setting up default sizes
my $xbox = 360;
my $ybox = 300;
my $boxsize = 2;

my $centerx = 0;

my $centery = 0;

my $wsize = 4;


my $pmax = $centerx + $wsize / 2;

my $pmin = $centerx - $wsize / 2;

my $qmax = $centery + $wsize / 2 * $ybox/$xbox;

my $qmin = $centery - $wsize / 2 * $ybox/$xbox;



my $A = ($pmax-$pmin)/$xbox;
my $C = ($qmax-$qmin)/$ybox;
#print "$pmax, $pmin, $qmax, $qmin, $A, $C\n";

my $kmax=100;

# setting up palette
my @palette = map { '#'.sprintf("%02x", int(sqrt($_/$kmax)*256)).
					sprintf("%02x", int(($_/$kmax)**3*256)).
					sprintf("%02x", int(sin(3.14159*$_/$kmax)*256)) } (0..$kmax-1);
$palette[-1] = '#000000';

# Create the main window
my $win = new Gtk2::Window ( "toplevel" );
$win->signal_connect ("delete_event", sub { Gtk2->main_quit; });
#$win->signal_connect ("configure_event", \&win_expose);
$win->set_title( "Julia set demo" );
$win->set_border_width (6);
#$win->maximize;
$win->set_resizable (0);
$win->resize(700, 500);

my $vbox = Gtk2::VBox->new (0, 6);
$win->add ($vbox);

# Creating the canvas
my $canvas = Goo::Canvas->new();
$canvas->set_size_request($xbox*$boxsize, $ybox*$boxsize);
$canvas->set_bounds(0, 0, $xbox*$boxsize, $ybox*$boxsize);
my $white = Gtk2::Gdk::Color->new (0xFFFF, 0xFFFF, 0xFFFF);
$canvas->modify_base('normal', $white );
$vbox->pack_start($canvas, 1, 1, 0);  

my $root = $canvas->get_root_item();
my $g = Goo::Canvas::Group->new($root); 

my $rect = Goo::Canvas::Rect->new(
	$g, 0, 0, $xbox*$boxsize, $ybox*$boxsize,
	'line-width' => 1,
	'stroke-color' => 'white', #invisible on white bg
	'fill-color' => 'white',   # must be filled for mouse event sensitivity
	'title' => 'bg_white_rect',
);

# Creating the colored rectangles that make up the Julia set
my @pixels;
foreach my $x (0..$xbox-1) {
	foreach my $y (0..$ybox-1) {
		$pixels[$x][$y] = Goo::Canvas::Rect->new(
			$g, 
			$x*$boxsize, 
			$y*$boxsize,
			$boxsize, 
			$boxsize,
			'line-width' => 0,
			#'stroke-color' => 'white', 
			'fill-color' =>  'white',   
			#'title' => 'bg_white_rect',
		);			
	}
}
$g->signal_connect('motion-notify-event', \&on_background_motion_notify);

$canvas->can_focus(TRUE);
$canvas->grab_focus($root);

$win->show_all;

main Gtk2;

# replotting on mouse movement
sub on_background_motion_notify {
	my ($group, $item, $ev) = @_;
	
	my $cy = $C*int(($ev->y)/$boxsize) + $qmin; #///
	my $cx = $A*int(($ev->x)/$boxsize) + $pmin;
	
	#print $ev->x," ,",$ev->y," ,$cx ,$cy\n";
	my ($k, $x, $y, $x2, $y2);
	
	foreach my $p (0..$xbox-1) {
		foreach my $q (0..$ybox-1) {
			$k = 0;
			$x = $A*$p + $pmin;
			$y = $C*$q + $qmin;
			$x2 = $x*$x; $y2 = $y*$y;
			while ($x2+$y2<4 && $k<$kmax) {

				$y=2*$x*$y+$cy;

				$x=$x2-$y2+$cx;

				$x2=$x*$x;

				$y2=$y*$y;

				$k++;

			}
			$pixels[$p][$q]->set(
				'fill-color' => $palette[$k],     
			);			
		}
	}
	return TRUE;
}