RosettaCodeData/Task/Bitmap-Midpoint-circle-algo.../Modula-3/bitmap-midpoint-circle-algo...

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use MONKEY_TYPING;
augment class Pixel { method Str { "$.R $.G $.B" } }
augment class Bitmap {
method P3 {
join "\n", «P3 "$.width $.height" 255»,
do for ^$.height { join ' ', @.data[]»[$_] }
}
method raster-circle ( $x0, $y0, $r, Pixel $value ) {
my $f = 1 - $r;
my $ddF_x = 0;
my $ddF_y = -2 * $r;
my ($x, $y) = 0, $r;
self.set-pixel($x0, $y0 + $r, $value);
self.set-pixel($x0, $y0 - $r, $value);
self.set-pixel($x0 + $r, $y0, $value);
self.set-pixel($x0 - $r, $y0, $value);
while $x < $y {
if $f >= 0 {
$y--;
$ddF_y += 2;
$f += $ddF_y;
}
$x++;
$ddF_x += 2;
$f += $ddF_x + 1;
self.set-pixel($x0 + $x, $y0 + $y, $value);
self.set-pixel($x0 - $x, $y0 + $y, $value);
self.set-pixel($x0 + $x, $y0 - $y, $value);
self.set-pixel($x0 - $x, $y0 - $y, $value);
self.set-pixel($x0 + $y, $y0 + $x, $value);
self.set-pixel($x0 - $y, $y0 + $x, $value);
self.set-pixel($x0 + $y, $y0 - $x, $value);
self.set-pixel($x0 - $y, $y0 - $x, $value);
}
}
}