NAME

       Math::ConvexHull::MonotoneChain - Andrew's monotone chain algorithm for finding a convex
       hull in 2D

SYNOPSIS

         use Math::ConvexHull::MonotoneChain 'convex_hull';
         my $ch = convex_hull(
           [
             [0, 0],
             [0, 1],
             [1, 0],
             [0.5, 0.5],
             [1, 1],
           ]
         );

         # $ch is now:
         # [ [0, 0],
         #   [1, 0],
         #   [1, 1],
         #   [0, 1], ]

DESCRIPTION

       This is somewhat experimental still.

       This (XS) module optionally exports a single function "convex_hull" which calculates the
       convex hull of the input points and returns it.  The algorithm is "O(n log n)" due to
       having to sort the input list, but should be somewhat faster than a plain Graham's scan
       (also "O(n log n)") in practice since it avoids polar coordinates.

FUNCTIONS

   convex_hull
       Expects an array ref of points as input, returns an array ref of of the points in the
       convex hull, ordered counter-clockwise.

       point refers to an array reference containing an X, and a Y coordinate.

       For less than three input points, this will return an array reference whose elements are
       the input points (without cloning).

SEE ALSO

       Math::ConvexHull, which uses Graham's scan in pure Perl.

AUTHOR

       Steffen Mueller, <smueller@cpan.org>

COPYRIGHT AND LICENSE

       Copyright (C) 2011 by Steffen Mueller

       This library is free software; you can redistribute it and/or modify it under the same
       terms as Perl itself, either Perl version 5.8.0 or, at your option, any later version of
       Perl 5 you may have available.