Math::Bezier - solution of Bezier Curves |
Math::Bezier - solution of Bezier Curves
use Math::Bezier;
# create curve passing list of (x, y) control points my $bezier = Math::Bezier->new($x1, $y1, $x2, $y2, ..., $xn, $yn);
# or pass reference to list of control points my $bezier = Math::Bezier->new([ $x1, $y1, $x2, $y2, ..., $xn, $yn]);
# determine (x, y) at point along curve, range 0 -> 1 my ($x, $y) = $bezier->point(0.5);
# returns list ref in scalar context my $xy = $bezier->point(0.5);
# return list of 20 (x, y) points along curve my @curve = $bezier->curve(20);
# returns list ref in scalar context my $curve = $bezier->curve(20);
This module implements the algorithm for the solution of Bezier curves as presented by Robert D. Miller in Graphics Gems V, ``Quick and Simple Bezier Curve Drawing''.
A new Bezier curve is created using the new()
constructor, passing a list
of (x, y) control points.
use Math::Bezier;
my @control = ( 0, 0, 10, 20, 30, -20, 40, 0 ); my $bezier = Math::Bezier->new(@control);
Alternately, a reference to a list of control points may be passed.
my $bezier = Math::Bezier->new(\@control);
The point($theta)
method can then be called on the object, passing a
value in the range 0 to 1 which represents the distance along the
curve. When called in list context, the method returns the x and y
coordinates of that point on the Bezier curve.
my ($x, $y) = $bezier->point(0.5); print "x: $x y: $y\n
When called in scalar context, it returns a reference to a list containing the x and y coordinates.
my $point = $bezier->point(0.5); print "x: $point->[0] y: $point->[1]\n";
The curve($n)
method can be used to return a set of points sampled
along the length of the curve (i.e. in the range 0 <= $theta <= 1).
The parameter indicates the number of sample points required,
defaulting to 20 if undefined. The method returns a list of ($x1,
$y1, $x2, $y2, ..., $xn, $yn) points when called in list context, or
a reference to such an array when called in scalar context.
my @points = $bezier->curve(10);
while (@points) { my ($x, $y) = splice(@points, 0, 2); print "x: $x y: $y\n"; }
my $points = $bezier->curve(10);
while (@$points) { my ($x, $y) = splice(@$points, 0, 2); print "x: $x y: $y\n"; }
Andy Wardley <abw@kfs.org>
Graphics Gems 5, edited by Alan W. Paeth, Academic Press, 1995, ISBN 0-12-543455-3. Section IV.8, 'Quick and Simple Bezier Curve Drawing' by Robert D. Miller, pages 206-209.
Math::Bezier - solution of Bezier Curves |