Math::Polygon::Clip - frame a polygon in a square

Math::Polygon::Clip
is a Exporter

my @poly = ( [1,2], [2,4], [5,7], [1, 2] );
my @box = ( $xmin, $ymin, $xmax, $ymax );
my $boxed = polygon_clip \@box, @poly;

Cut-off all parts of the polygon which are outside the box

**polygon_fill_clip1**(\@box, @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**(\@box, @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**( \@box, $out-$poly, [$in-$polys] )
**To be implemented**. A surrounding polygon, with possible
inclussions.

**polygon_line_clip**(\@box, @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]

This module is part of Math-Polygon distribution version 1.10, built on January
03, 2018. Website:

*http://perl.overmeer.net/CPAN/*
Copyrights 2004-2018 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://dev.perl.org/licenses/*