NAME

       Math::Polygon::Surface - Polygon with exclusions

SYNOPSIS

        my $outer   = Math::Polygon->new( [1,2], [2,4], [5,7], [1,2] );
        my $surface = Math::Polygon::Surface->new($outer);

DESCRIPTION

       A surface is one polygon which represents the outer bounds of an array, plus optionally a
       list of polygons which represent exclusions from that outer polygon.

METHODS

   Constructors
       $obj->new([%options], [$polygons], %options)
       Math::Polygon::Surface->new([%options], [$polygons], %options)
           You may add %options after and/or before the $polygons.  You may also use the "outer"
           and "inner" options.  $polygons are references to ARRAYs of points, each an ARRAY of X
           and Y, but better instantiated Math::Polygon objects.

            -Option--Default
             inner   []
             outer   undef

           inner => ARRAY-OF-POLYGONS
             The inner polygons, zero or more Math::Polygon objects.

           outer => POLYGON
             The outer polygon, a Math::Polygon.

   Attributes
       $obj->inner()
           Returns a list (often empty) of inner polygons.

       $obj->outer()
           Returns the outer polygon.

   Simple calculations
       area()
           Returns the area enclosed by the outer polygon, minus the areas of the inner polygons.
           See method Math::Polygon::area().

       $obj->bbox()
           Returns a list with four elements: (xmin, ymin, xmax, ymax), which describe the
           bounding box of the surface, which is the bbox of the outer polygon.  See method
           Math::Polygon::bbox().

       $obj->perimeter()
           The length of the border: sums outer and inner perimeters.  See method
           Math::Polygon::perimeter().

   Clipping
       $obj->fillClip1($box)
           Clipping a polygon into rectangles can be done in various ways.  With this algorithm,
           the parts of the polygon which are outside the $box are mapped on the borders.

           All polygons are treated separately.

       $obj->lineClip($box)
           Returned is a list of ARRAYS-OF-POINTS containing line pieces from the input surface.
           Lines from outer and inner polygons are undistinguishable.  See method
           Math::Polygon::lineClip().

       $obj->string()
           Translate the surface structure into some string.  Use Geo::WKT if you need a
           standardized format.

           Returned is a single string possibly containing multiple lines.  The first line is the
           outer, the other lines represent the inner polygons.

DIAGNOSTICS

       Error: surface requires outer polygon

SEE ALSO

       This module is part of Math-Polygon distribution version 1.03, built on January 21, 2014.
       Website: http://perl.overmeer.net/geo/

LICENSE

       Copyrights 2004,2006-2014 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