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(\@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]

SEE ALSO

       This module is part of Math-Polygon distribution version 1.10, built on January 03, 2018.
       Website: http://perl.overmeer.net/CPAN/

LICENSE

       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/