Thanks for the extension

hossman++. This works pretty
good. Only problem is, I gave you a very sub-optimal
algorithm. Ok for 40 x 80, too slow for 200 x 200.

The big kludge was adding 8 points in adjacent squares.
This isn't necessary. Instead calculate the x and y
distances separately. If a distance is greater than .5,
adjust it to 1 - distance. If a point is .7 from a v-point,
it is .3 from a corresponding v-point in an adjacent square.

This means about 90% fewer v-points to test against, so
this is many times faster.

So here's another version based on your changes with an
additional color option.

YuckFoo

`#!/usr/bin/perl
use strict;
use GD;
my $ROWS = 200; # number of rows
my $COLS = 200; # number of columns
my $POINTS = 12; # number of Voronoi points
my $COLORS = 128; # number of colors
my $INNER = [255, 255, 0]; # inner color (red, green, blue)
my $OUTER = [ 0, 32, 0]; # outer color (red, green, blue)
my $xfact = 1 / $COLS;
my $yfact = 1 / $ROWS;
# Allocate some colors
my $img = new GD::Image($COLS, $ROWS);
my $colors = makecolors($img, $COLORS, $INNER, $OUTER);
my (@xs, @ys);
# Pick some random points
for (0..$POINTS-1) {
push (@xs, rand());
push (@ys, rand());
}
# Calculate screen
for my $yi (0..$ROWS-1) {
my $y = $yi * $yfact;
for my $xi (0..$COLS-1) {
my $x = $xi * $xfact;
my ($best, $good) = closest($x, $y, \@xs, \@ys);
$img->setPixel($xi, $yi, $colors->[$COLORS * ($best / $good)]
+);
}
}
binmode STDOUT;
print $img->png();
#-----------------------------------------------------------
sub closest {
my ($x, $y, $xs, $ys) = @_;
my ($dist, $best, $good);
for (my $i = 0; $i < @$xs; $i++) {
my $xdiff = abs($x - $xs->[$i]);
my $ydiff = abs($y - $ys->[$i]);
if ($xdiff > .5) { $xdiff = 1 - $xdiff; }
if ($ydiff > .5) { $ydiff = 1 - $ydiff; }
$dist = sqrt($xdiff * $xdiff + $ydiff * $ydiff);
if ($i == 0 || $dist < $best) { ($good, $best) = ($best, $dis
+t); }
elsif ($i == 1 || $dist < $good) { $good = $dist; }
}
return ($best, $good);
}
#-----------------------------------------------------------
sub makecolors {
my ($img, $num, $beg, $end) = @_;
my (@colors);
my $red = ($end->[0] - $beg->[0]) / $num;
my $green = ($end->[1] - $beg->[1]) / $num;
my $blue = ($end->[2] - $beg->[2]) / $num;
for (my $i = 0; $i < $num; $i++) {
$beg->[0] += $red;
$beg->[1] += $green;
$beg->[2] += $blue;
push (@colors, $img->colorAllocate(@$beg));
}
return \@colors;
}
`

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