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

$any->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

Cast by new()

SEE ALSO

This module is part of Math-Polygon version 2.00, built on September 04, 2025. Website: http://perl.overmeer.net/CPAN/

LICENSE

For contributors see file ChangeLog.

This software is copyright (c) 2004-2025 by Mark Overmeer.

This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.