NAME
    Math::Geometry::Planar::GPC::Polygon - OO wrapper to gpc library

Status
    Successfully used in minor production use under perl 5.6.1 and 5.8.3.
    Your mileage may vary (see NO WARRANTY.)

AUTHOR
      Eric L. Wilhelm
      ewilhelm at sbcglobal dot net
      http://pages.sbcglobal.net/mycroft/

Copyright
    Copyright 2004 Eric L. Wilhelm

License
    This module and its C source code (functions.c) are distributed under
    the same terms as Perl. See the Perl source package for details.

    You may use this software under one of the following licenses:

      (1) GNU General Public License
        (found at http://www.gnu.org/copyleft/gpl.html)
      (2) Artistic License
        (found at http://www.perl.com/pub/language/misc/Artistic.html)

    The General Polygon Clipping library (gpc.c and gpc.h) is distributed as
    "free for non-commercial use". See gpc.c for details. A copy of these
    files has been included with this distribution strictly for convenience
    purposes, but YOU ARE RESPONSIBLE FOR ADHERING TO BOTH THE GPC LICENSE
    AND THE LICENSE OF THIS MODULE. Note that the C library is authored by
    Alan Murta.

    You may want to check the GPC home page for a more current version:

      http://www.cs.man.ac.uk/aig/staff/alan/software/

Portability
    This module successfully compiles on i386 and solaris architectures
    according to the cpan testers results. Hopefully, versions after 0.04
    will work on WIN32. I don't have any non-linux machines, so feel free to
    send patches.

NO WARRANTY
    This code comes with ABSOLUTELY NO WARRANTY of any kind.

Changes
      0.01 - First public release.
      0.02 - Added API documentation.
      0.03 - Fix to allocation error.
             Possibly Fixed WIN32 compile problem?
      0.04 - Twiddling with WIN32 compile problem (last try)
      0.05 - Corrected license statements.

Constructors
  new
    Traditional constructor, returns a blessed reference to the underlying C
    struct.

      use Math::Geometry::Planar::GPC::Polygon;
      my $gpc = Math::Geometry::Planar::GPC::Polygon->new();

  new_gpc
    An optionally imported constructor, for those of you who don't like to
    type so much.

      use Math::Geometry::Planar::GPC::Polygon qw(new_gpc);
      my $gpc = new_gpc();

Bound Functions
    These are the functions provide by the Inline-C code. See functions.c in
    the source package for intimate details.

  from_file
    Loads a from a file into your gpc object. See the GPC library
    documentation for details.

      $gpc->from_file($filename, $want_hole);

  to_file
    Writes to a file.

      $gpc->to_file($filename, $want_hole);

  clip_to
    Clips the $gpc object to the $othergpc object.

    $action may be any of the following:

      INTERSECT
      DIFFERENCE
      UNION

      $gpc->clip_to($othergpc, $action);

    Be wary. This interface may need to change.

  add_polygon
    Adds a polygon to the gpc object. @points is a list of array references
    which describe the point of the polygon. $hole is 1 or 0 (0 to not add a
    hole.)

      $gpc->add_polygon(\@points, $hole);

  get_polygons
    Gets the polygons from the gpc object. I'm not sure how to tell you if
    they are holes or not. @pgons will be a list of refs to lists of refs.

      @pgons = $gpc->get_polygons();

Helper Functions
    Pure-perl implementation from here down.

  as_string
      $gpc->as_string();