in reply to Generating Fractals with Perl?

Here's a fairly crude Mandelbrot I prepared earlier: 

#!/usr/bin/perl -w

use strict;
use GD;

use vars qw($P @Q $col $row @colours );

my ($maxcol,
    $maxrow,
    $max_colours,
    $max_iterations,
    $max_size )       = (640,350,16,512,4);

my ($XMax,$XMin,$YMax,$YMin) = (1.2,-2.0,1.2,-1.2);

my $deltaP = ($XMax - $XMin) / $maxcol;
my $deltaQ = ($YMax - $YMin) / $maxrow;

$Q[0] = $YMax;

my $image = new GD::Image($maxcol,$maxrow);

for ( 0 .. $max_colours - 1)
  {
    $colours[$_] = $image->colorAllocate(int(rand(256)),
                                         int(rand(256)),
                                         int(rand(256)));
  }

for( 1 .. $maxrow )
  {
    $Q[$_] = $Q[$_ -1] - $deltaQ;
  }

$P = $XMin;

for $col ( 0 .. $maxcol -1 )
  {
    for $row ( 0 .. $maxrow - 1)
      {
        my ($X,$Y,$XSquare,$YSquare) = (0,0,0,0);

        my $colour = 1;

        while (( $colour < $max_iterations ) &&
               (($XSquare + $YSquare ) < $max_size ))
           {
             $XSquare = $X * $X;
             $YSquare = $Y * $Y;

             $Y *= $X;
             $Y += $Y + $Q[$row];
             $X = $XSquare - $YSquare + $P;
             $colour++;
           }
           $image->setPixel($col,$row,$colours[$colour % $max_colours]
+);
       }
     $P += $deltaP;
   }

open(PNG,">image$$.png") || die "Cannot open output - $!\n";
binmode(PNG);
print PNG $image->png;
close(PNG);

[download]

If you look in the examples for my module Linux::Svgalib there are some further examples.

/J\

Replies are listed 'Best First'.
Another example
by gellyfish (Monsignor) on Mar 09, 2002 at 19:10 UTC

    And this one draws a random Dragon Outline as a CGI program : 

    #!/usr/bin/perl -w

use CGI qw(:standard);
use strict;
use GD;

use vars qw($magnitude $P $Q $scale);

my ($x_centre,$y_centre) = (320,175);

if ( scalar param() < 3 )
  {
    my @configs = map {chomp; [ split ]} <DATA>; 
    ($P,$Q,$scale) = @{ $configs[rand @configs] };
   }
else
  {
   $P = param('real');
   $Q = param('imaginary');
   $scale = param('scale');
  }

   my $image = new GD::Image($x_centre * 2,$y_centre * 2);

   my $back_colour = $image->colorAllocate(255,255,255);
   my $fore_colour = $image->colorAllocate(0,0,0);

   my ($x,$y) = (0.50001,0);

   $magnitude = ($P*$P) + ($Q*$Q);

   $P = 4*$P/$magnitude;
   $Q = -4*$Q/$magnitude;

   $scale = $x_centre * $scale;

   for ( 1 .. 12000 )
      {
        my $temp_x = ($x * $P ) - ($y * $Q );
        $y = ($x * $Q) + ($y * $P );
        my $temp_y = $y;
        $x = 1 - $temp_x;

        $magnitude = sqrt(($x * $x ) + ($y * $y));

        $y = sqrt((-$x + $magnitude)/2);
        $x = sqrt(($x + $magnitude)/2);

        ($x = -$x) if ($temp_y < 0 );

        if ( rand() < 0.5 )
          {
            $x = -$x;
            $y = -$y;
          }

        $x = (1- $x) / 2;

        $y = $y / 2;

        my $col = int(($scale * ($x - 0.5 )) + $x_centre);
        my $row = int($y_centre - ($scale * $y));

         if ( ($_ > 0 ) &&
              ($col >= 0 ) &&
              ($col < (2 * $x_centre)) &&
              ($row >= 0 ) &&
              ($row < ($y_centre * 2 )))
            {
              $image->setPixel($col,$row,$fore_colour);
            }
     }

   print header('image/png');
   binmode(STDOUT);
   print $image->png;
__END__
1.646009    0.967049 0.75
2.447261    -0.967049 0.75
1.325508    0.786533 0.75
1.415414    0.856803 0.75
1.255399    0.691977 0.75
2.792809    -0.657593 0.75
3.018153    -0.098854 0.75
2.998122    0.004298 0.75

    [download]

    /J\

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