Sierpinski pentagon: Difference between revisions

=={{header|Perl}}==

{{libheader|ntheory}}

{{trans|Perl 6}}

<lang perl>use ntheory qw(todigits);

use Math::Complex;

$sides = 5;

$order = 5;

$dim = 250;

$scale = ( 3 - 5**.5 ) / 2;

push @orders, ((1 - $scale) * $dim) * $scale ** $_ for 0..$order-1;

open $fh, '>', 'sierpinski_pentagon.svg';

print $fh qq|<svg height="@{[$dim*2]}" width="@{[$dim*2]}" style="fill:blue" version="1.1" xmlns="http://www.w3.org/2000/svg">\n|;

$tau = 2 * 4*atan2(1, 1);

push @vertices, cis( $_ * $tau / $sides ) for 0..$sides-1;

for $i (0 .. -1+$sides**$order) {

@base5 = todigits($i,5);

@i = ( ((0)x(-1+$sides-$#base5) ), @base5);

@v = @vertices[@i];

$vector = 0;

$vector += $v[$_] * $orders[$_] for 0..$#orders;

my @points;

for (@vertices) {

$v = $vector + $orders[-1] * (1 - $scale) * $_;

push @points, sprintf '%.3f %.3f', $v->Re, $v->Im;

}

print $fh pgon(@points);

}

sub cis { Math::Complex->make(cos($_[0]), sin($_[0])) }

sub pgon { my(@q)=@_; qq|<polygon points="@q" transform="translate($dim,$dim) rotate(-18)"/>\n| }

print $fh '</svg>';

close $fh;</lang>

[https://github.com/SqrtNegInf/Rosettacode-Perl5-Smoke/blob/master/ref/sierpinski_pentagon.svg Sierpinski pentagon] (offsite image)