B-spline: Difference between revisions
Added Perl
(added Raku programming solution) |
SqrtNegInf (talk | contribs) (Added Perl) |
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{{out}}
Outputs a graphical representation of a B-spline.
=={{header|Perl}}==
{{trans|Raku}}
<lang perl>use strict;
use warnings;
use Class::Struct;
use Cairo;
{ package Line;
struct( A => '@', B => '@');
}
my ($WIDTH, $HEIGHT, $W_LINE, $CURVE_F, $DETACHED, $OUTPUT ) =
( 400, 400, 2, 0.25, 0, 'run/b-spline.png' );
my @pt = (
[171, 171], [185, 111], [202, 109], [202, 189], [328, 160], [208, 254],
[241, 330], [164, 252], [ 69, 278], [139, 208], [ 72, 148], [168, 172]
);
my $cnt = @pt;
sub angle {
my($g) = @_;
atan2 $g->B->[1] - $g->A->[1], $g->B->[0] - $g->A->[0]
}
sub control_points {
my($g, $l) = @_;
my $h = Line->new;
my $lgt = sqrt( ($g->B->[0] - $l->A->[0])**2 + ($g->B->[1] - $l->A->[1])**2 );
@{$h->B} = @{$l->A};
@{$h->A} = ($g->B->[0] - $lgt * cos(angle $g) , $g->B->[1] - $lgt * sin(angle $g));
my $a = angle $h;
my @p1 = ($g->B->[0] + $lgt * cos($a) * $CURVE_F, $g->B->[1] + $lgt * sin($a) * $CURVE_F);
@{$h->A} = @{$g->B};
@{$h->B} = ($l->A->[0] + $lgt * cos(angle $l) , $l->A->[1] + $lgt * sin(angle $l));
$a = angle $h;
my @p2 = ($l->A->[0] - $lgt * cos($a) * $CURVE_F, $l->A->[1] - $lgt * sin($a) * $CURVE_F);
\@p1, \@p2
}
my $surf = Cairo::ImageSurface->create ('argb32', $WIDTH, $HEIGHT);
my $cr = Cairo::Context->create ($surf);
$cr->set_line_width($W_LINE);
$cr->move_to($pt[$DETACHED - 1 + $cnt][0], $pt[$DETACHED - 1 + $cnt][1]);
my Line ($g,$l);
for my $j ($DETACHED..$cnt-1) {
$g = Line->new( A=>$pt[($j + $cnt - 2) % $cnt], B=>$pt[($j + $cnt - 1) % $cnt]);
$l = Line->new( A=>$pt[($j + $cnt + 0) % $cnt], B=>$pt[($j + $cnt + 1) % $cnt]);
my($p1,$p2) = control_points($g, $l);
$cr->curve_to($$p1[0], $$p1[1], $$p2[0], $$p2[1], $pt[$j][0], $pt[$j][1]);
}
$cr->stroke;
$surf->write_to_png($OUTPUT);</lang>
Output: [https://raw.githubusercontent.com/SqrtNegInf/Rosettacode-Perl-Smoke/master/ref/b-spline.png b-spline.png] (offsite image)
=={{header|Phix}}==
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