math::bezier(3pm) [debian man page]

Bezier(3pm)						User Contributed Perl Documentation					       Bezier(3pm)

NAME

       Math::Bezier - solution of Bezier Curves

SYNOPSIS

	   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);

DESCRIPTION

       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


       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]
";

       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
";
	   }

	   my $points = $bezier->curve(10);

	   while (@$points) {
	       my ($x, $y) = splice(@$points, 0, 2);
	       print "x: $x  y: $y
";
	   }

AUTHOR

       Andy Wardley <abw@kfs.org>

SEE ALSO

       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.

perl v5.10.1							    2000-10-19							       Bezier(3pm)