Sometimes I use Perl to generate cheesy graphics to visualize math or geometry concepts. The latest effort was rather pleasing despite the cheese so I offer it here.

This program calculates and displays Voronoi neighborhoods. The neighborhoods wrap so the image (if it were one) is tileable. There are many examples of Voronoi spots found in nature, quite an interesting subject (search Google).

Any suggestions for a better @CHARS to use?

SpotFoo 

#!/usr/bin/perl
      
   use strict;

   my @CHARS = split('', ' .,-+*$&#@');

   my ($XMIN, $XMAX) = qw(0 1);
   my ($YMIN, $YMAX) = qw(0 1);
   my ($ROWS, $COLS) = qw(40 80);
   my $POINTS        = 8;
   my $REPEAT        = 0;

   my $xfact = ($XMAX - $XMIN) / $COLS;
   my $yfact = ($YMAX - $YMIN) / $ROWS;

   my (@screen, @xs, @ys);

   # Pick some random points
   for (0..$POINTS-1) {
      my ($xrand, $yrand) = (rand(), rand());
      for my $xoffset (-1..1) {
         for my $yoffset (-1..1) {
            push (@xs, $xrand + $xoffset);
            push (@ys, $yrand + $yoffset);
         }
      }
   }

   # Calculate screen
   for my $yi (0..$ROWS-1) {
      my $y = $YMIN + $yi * $yfact;
      for my $xi (0..$COLS-1) {
         my $x = $XMIN + $xi * $xfact;
         my ($best, $good) = closest($x, $y, \@xs, \@ys);
         $screen[$xi][$yi] = $CHARS[int(10 * ($best / $good))];
      }
   }

   # Print screen
   for (0..$REPEAT) {
      for my $yi (0..$ROWS-1) {
         for my $xi (0..$COLS-1) {
            print "$screen[$xi][$yi]";
         }
         print "\n";
      }
   }

#-----------------------------------------------------------
sub closest {

   my ($x, $y, $xs, $ys) = @_;
   my ($dist, $best, $good);

   for (my $i = 0; $i < @$xs; $i++) {
      $dist = sqrt(($x - $xs->[$i])**2 + ($y - $ys->[$i])**2);

      if    ($i == 0 || $dist < $best) { ($good, $best) = ($best, $dis
+t); }
      elsif ($i == 1 || $dist < $good) { $good = $dist; }
   }

   return ($best, $good);
}

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In reply to Perl Spots by YuckFoo

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