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 merge %options with @polygons. You may also use the "outer" and "inner" options.

Each polygon is a references to an ARRAY of points, each an ARRAY of X and Y, but better pass Math::Polygon objects.

 -Option--Default
  inner   []
  outer   undef

inner => \@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

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/