Julia set: Difference between revisions

=={{header|Perl 6}}==

[[File:Julia-set-perl6.png|250px|thumb|right]]

{{trans|Perl}} with the pallette swapped, just because.

{{works with|Rakudo|2016.03}}

<lang perl6>use Image::PNG::Portable;

my ($w, $h) = (800, 600);

my $out = Image::PNG::Portable.new: :width($w), :height($h);

my $maxIter = 255;

my ($cX, $cY) = (-0.7, 0.27015);

julia($out);

$out.write: 'Julia-set-perl6.png';

sub julia ( $png ) {

for ^$w -> $x {

for ^$h -> $y {

my $zx = (1.5 * ($x - $w / 2) / (0.5 * $w));

my $zy = (($y - $h / 2) / (0.5 * $h));

my $i = $maxIter;

while ($zx² + $zy² < 4 and $i > 1) {

($zy, $zx) = (2.0 * $zx * $zy + $cY, $zx² - $zy² + $cX);

$i--;

}

$png.set( $x, $y, |hsv2rgb($i / $maxIter * 360, 1, $i > 1 ?? 1 !! 0) );

}

}

}

sub hsv2rgb ( $h, $s, $v ){

my $c = $v * $s;

my $x = $c * (1 - abs( (($h/60) % 2) - 1 ) );

my $m = $v - $c;

my ($r, $g, $b);

given $h {

when 0..^60 { ($r, $g, $b) = ($c, $x, 0) }

when 60..^120 { ($r, $g, $b) = ($x, $c, 0) }

when 120..^180 { ($r, $g, $b) = (0, $c, $x) }

when 180..^240 { ($r, $g, $b) = (0, $x, $c) }

when 240..^300 { ($r, $g, $b) = ($x, 0, $c) }

when 300..^360 { ($r, $g, $b) = ($c, 0, $x) }

}

( $r, $g, $b ) = map { (($_+$m) * 255).Int }, $r, $g, $b;

return $b, $g, $r;

}</lang>