#!/usr/bin/perl

use strict;
use diagnostics;
use Tk;

use constant TWO_PI             => 8 * atan2(1, 1);
use constant PHI                => 0.5 * (sqrt(5) + 1);
use constant GOLDEN             => (TWO_PI) - (TWO_PI) / PHI;
use constant DEFAULT_SEEDSIZE   => 5;
use constant DEFAULT_BEGIN      => 3;
use constant DEFAULT_END        => 180;
use constant DEFAULT_DIVERGENCE => 0.5;
use constant DEFAULT_RATE       => 5.0;

my $box = 400;
my ($seedsize, $begin, $end, $divergence, $rate);

reset_defaults();

my $main = MainWindow->new();
my $canvas = $main->Canvas(-background => 'white', -height => $box, -w
+idth => $box);
$canvas->pack();

my $frame_0 = $main->Frame()->pack(-side => 'bottom', -anchor => 'w');
my $redraw_button = $frame_0->Button(-text => "Redraw",
                                     -command => \&set_new_values)
  ->pack(-side => 'left');
my $reset_button = $frame_0->Button(-text => "Reset defaults",
                                    -command => \&reset_defaults)
  ->pack(-side => 'left');
my $exit_button = $frame_0->Button(-text => "Exit",
                                   -command => sub {$main->destroy;})
  ->pack(-side => 'right');

my $frame_1 = $main->Frame()->pack(-side => 'bottom', -anchor => 'w');
$frame_1->Label(-text => 'Rate:', -width => 12, -anchor => 'e')->pack(
+-side => 'left');
my $rateEnt = $frame_1->Entry (-width => 9 , -justify => 'right' , -va
+lidate => 'focus', -textvariable => \$rate) ->pack ( -side => 'left' 
+);

$frame_1->Label(-text => 'Divergence:', -width => 12, -anchor => 'e')-
+>pack(-side => 'left');
my $divEnt = $frame_1->Entry (-width => 9 , -justify => 'right', -vali
+date => 'focus', -textvariable => \$divergence) ->pack ( -side => 'le
+ft' );

my $frame_2 = $main->Frame()->pack(-side => 'bottom', -anchor => 'w');
$frame_2->Label(-text => 'Seed size:', -width => 12, -anchor => 'e')->
+pack(-side => 'left');
my $seedsizeEnt = $frame_2->Entry (-width => 9 , -justify => 'right' ,
+ -validate => 'focus', -textvariable => \$seedsize) ->pack ( -side =>
+ 'left' );

my $frame_3 = $main->Frame()->pack(-side => 'bottom', -anchor => 'w');
$frame_3->Label(-text => 'Begin angle:', -width => 12, -anchor => 'e')
+->pack(-side => 'left');
my $beginEnt = $frame_3->Entry (-width => 9 , -justify => 'right' , -v
+alidate => 'focus', -textvariable => \$begin) ->pack ( -side => 'left
+' );

$frame_3->Label(-text => 'End angle:', -width => 12, -anchor => 'e')->
+pack(-side => 'left');
my $endEnt = $frame_3->Entry (-width => 9 , -justify => 'right' , -val
+idate => 'focus', -textvariable => \$end) ->pack ( -side => 'left' );

drawseeds();

# $canvas->postscript(-width => $box, -height => $box, -file => "test.
+eps");

MainLoop;

######################################################################
+#########

sub drawseeds {
  for (my $theta = $begin * TWO_PI; $theta <= $end * TWO_PI; $theta +=
+ GOLDEN) {
    my $radius = $rate * $theta ** $divergence;
    my ($x, $y) = translate(r2p($radius, $theta));
    if ($radius > $box / 2) {
      print "Radius = $radius,\tTheta = $theta,\tx=$x,\ty=$y\n";
      last;
    }
    drawseed($x, $y);
  }
}

sub drawseed {
  my ($x, $y) = @_;
  $canvas->createOval($x - ($seedsize / 2), $y - ($seedsize / 2),
                      $x + ($seedsize / 2), $y + ($seedsize / 2),
                      -fill => 'black', -outline => 'black',
                      -tag => 'seed');
}

sub translate {
  my ($x, $y) = @_;
  return ($box / 2 + $x, $box / 2 - $y);
}

sub r2p {
  my ($radius, $theta) = @_;
  return ($radius * cos $theta, $radius * sin $theta);
}

sub reset_defaults {
  $seedsize   = DEFAULT_SEEDSIZE;
  $begin      = DEFAULT_BEGIN;
  $end        = DEFAULT_END;
  $divergence = DEFAULT_DIVERGENCE;
  $rate       = DEFAULT_RATE;
}

sub set_new_values {
  $seedsize   = $seedsizeEnt->get();
  $begin      = $beginEnt->get();
  $end        = $endEnt->get();
  $divergence = $divEnt->get();
  $rate       = $rateEnt->get();

  $canvas->delete("seed");
  drawseeds();
}
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