Hough transform: Difference between revisions
Added Perl 6 example
SqrtNegInf (talk | contribs) (Added Perl example) |
SqrtNegInf (talk | contribs) (Added Perl 6 example) |
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$ht->write(file => 'hough_transform.png');
</lang>
=={{header|Perl 6}}==
The <code>GD</code> module the output palette to 255 colors, so only transform darker pixels in the image.
{{trans|Perl}}
<lang perl6>use GD;
my $filename = 'pentagon.ppm';
my $in = open($filename, :r, :enc<iso-8859-1>);
my ($type, $dim, $depth) = $in.lines[^3];
my ($xsize,$ysize) = split ' ', $dim;
my ($width, $height) = 460, 360;
my $image = GD::Image.new($width, $height);
my @canvas = [255 xx $width] xx $height;
my $rmax = sqrt($xsize**2 + $ysize**2);
my $dr = 2 * $rmax / $height;
my $dth = π / $width;
my $pixel = 0;
my %cstore;
for $in.lines.ords -> $r, $g, $b {
$pixel++;
next if $r > 130;
my $x = $pixel % $xsize;
my $y = floor $pixel / $xsize;
for 0..^$width -> $k {
my $th = $dth*$k;
my $r = ($x*cos($th) + $y*sin($th));
my $iry = ($height/2 + ($r/$dr)round(1)).Int;
my $c = '#' ~ (@canvas[$iry][$k]--).base(16) x 3;
%cstore{$c} = $image.colorAllocate($c) if %cstore{$c}:!exists;
$image.pixel($k, $iry, %cstore{$c});
}
}
my $png_fh = $image.open("hough-transform.png", "wb");
$image.output($png_fh, GD_PNG);
$png_fh.close;</lang>
=={{header|Python}}==
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