Math::Polygon::Clip(3pm) User Contributed Perl Documentation Math::Polygon::Clip(3pm)
NAME
Math::Polygon::Clip - frame a polygon in a square
INHERITANCE
Math::Polygon::Clip
is a Exporter
SYNOPSIS
my @poly = ( [1,2], [2,4], [5,7], [1, 2] );
my @box = ( $xmin, $ymin, $xmax, $ymax );
my $boxed = polygon_clip @box, @poly;
DESCRIPTION
Cut-off all parts of the polygon which are outside the box
FUNCTIONS
polygon_fill_clip1(ARRAY-BOX, LIST-OF-POINTS)
Clipping a polygon into rectangles can be done in various ways. With this algorithm (which I designed myself, but may not be new), the
parts of the polygon which are outside the BOX are mapped on the borders. The polygon stays in one piece.
Returned is one list of points, which is cleaned from double points, spikes and superfluous intermediate points.
polygon_fill_clip2(ARRAY-BOX, LIST-OF-POINTS)
To be implemented. The polygon falls apart in fragments, which are not connected: paths which are followed in two directions are
removed. This is required by some applications, like polygons used in geographical context (country contours and such).
polygon_fill_clip3(ARRAY-BOX, OUT-POLY, [IN-POLYS])
To be implemented. A surrounding polygon, with possible inclussions.
polygon_line_clip(ARRAY-BOX, LIST-OF-POINTS)
Returned is a list of ARRAYS (possibly 0 long) containing line pieces from the input polygon (or line).
example:
my @points = ( [1,2], [2,3], [2,0], [1,-1], [1,2] );
my @bbox = ( 0, -2, 2, 2 );
my @l = polygon_line_clip @bbox, @points;
print scalar @l; # 1, only one piece found
my @first = @{$l[0]}; # first is [2,0], [1,-1], [1,2]
SEE ALSO
This module is part of Math-Polygon distribution version 1.02, built on September 19, 2011. Website: http://perl.overmeer.net/geo/
LICENSE
Copyrights 2004,2006-2011 by Mark Overmeer. For other contributors see ChangeLog.
This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself. See
http://www.perl.com/perl/misc/Artistic.html
perl v5.12.4 2011-09-19 Math::Polygon::Clip(3pm)