Hi Monks,
I'm having problems getting the zoom on this to center on the spot clicked on - it almost works, and I'm fairly sure that:

1. My formula for working out where to center the image is wrong
2. And/or I should be remembering the last zoom location

#  creates canvas, zooms *2 on click, centering on location
#  clicked on... or should...

use strict;
use Tk;

my $c_size = 100;
my $scale = 1;

my $mw = MainWindow -> new;
my $canvas = $mw -> Canvas(-height=>$c_size, -width=>$c_size) -> pack;
$canvas -> Tk::bind('all', '<ButtonPress-1>' => \&MakeMan);
MakeMan();

MainLoop;

sub MakeMan(){
  my ($e, $canv_x, $canv_y)=(0,$c_size/2,$c_size/2);
  if($scale > 1){
    $e = $canvas -> XEvent;
    $canv_x = $e->x;
    $canv_y = $e->y;
  }

  my $icount = 1;
#problem here...
  my $i = -2/$scale + (($canv_y-($c_size/2)) / ($c_size/$scale));# + $
+lasti;
  my $rgb;
  while($icount <= $c_size){
#... and here...
    my $r = -2/$scale + (($canv_x-($c_size/2)) / ($c_size/$scale));# +
+ $lastr;
    my $rcount = 1;
    while($rcount <= $c_size){
      my $tr = $r;
      my $ti = $i;
      $rgb = '#000000';
      for my $n(1..15){
        ($tr, $ti) = (($tr ** 2) - ($ti ** 2) + ($r), (2 * $tr * $ti) 
++ ($i));
        if((($tr * $tr) + ($ti * $ti)) > 4){
          $rgb = '#ffffff';
          last;
        }
      }
      $canvas -> createLine($rcount, $icount, $rcount+1, $icount, -fil
+l => $rgb, -width => 1);
      $rcount ++;
      $r += (4/$scale)/$c_size;
    }
    $icount ++;
    $i += (4/$scale)/$c_size;
  }
  $scale = $scale * 2;
}
[download]

map{$a=1-$_/10;map{$d=$a;$e=$b=$_/20-2;map{($d,$e)=(2*$d*$e+$a,$e**2
-$d**2+$b);$c=$d**2+$e**2>4?$d=8:_}1..50;print$c}0..59;print$/}0..20
[download]