NAME

Shape::RegularPolygon - Object that treats the shape of the regular polygon

SYNOPSIS

use Shape::RegularPolygon;

# Create a regular polygon
$polygon = new Shape::RegularPolygon;
$polygon->center(100, 50);
$polygon->sides(3);
$polygon->radius(100);
$polygon->angle(3.14 / 6);

# By named parameter
$polygon = new Shape::RegularPolygon(CenterX => 100,
                                     CenterY =>  50,
                                     Sides => 3,
                                     Radius => 100,
                                     Angle => 3.14 / 6);

# get vertexes
@points = $polygon->points

DESCRIPTION

Shape::RegularPolygon is a class that treats the shape of the regular polygon. This object creates and returns vertex list of specified regular polygon.

Construction

Simple construction

new Shape::RegularPolygon;

When the parameter is omitted, the equilateral triangle is made in default. The parameter can be set later by using method.

Construction with named parameters

new Shape::RegularPolygon(named parameters);

When you construct object, you can specify some parameters. See below about named parameters.

Parameters

CenterX, CenterY

Position of regular polygon

Sides

Building n-sides polygon. When four is specified, square is made. It must be a value of three or more.

Radius

Circumradius of regular polygon

Angle

Rotate a polygon in radians (clockwise).

METHODS

center(x, y)

Set position of polygon. Returns current position, when parameters are omitted.

$shape->center(100, 200);
($x, $y) = $shape->center;

sides(n)

Set the number of sides. Returns the number of sides, when parameters are omitted.

$shape->sides(5);
$n = $shape->sides;

radius(r)

Set circumradius of polygon. Returns current circumradius, when parameters are omitted.

$shape->radius(100);
$r = $shape->radius;

angle(rad)

Set rotation angle. Returns current angle, when parameters are omitted. The rad is in radian. and clockwise.

$shape->angle(3.14 / 6);	# 30 degree
$rad = $shape->angle;

points()

Returns vertexes list of polygon as follows.

(
  {x => x0, y => y0},    # Vertex0
  {x => x1, y => y1},    # Vertex1
     :
     :
)

Example

The following script builds png image file that regular pentagon was drawn.

#!/usr/bin/perl
use strict;
use warnings;
use Shape::RegularPolygon;
use GD;

my $shape = new Shape::RegularPolygon;
$shape->center(150, 100);
$shape->sides(5);

my $im = new GD::Image(300, 200);
$im->fill(0, 0, $im->colorAllocate(0xff, 0xff, 0xff));

my $poly = new GD::Polygon;
$poly->addPt($_->{x}, $_->{y}) foreach $shape->points;

$im->filledPolygon($poly, $im->colorAllocate(0x80, 0xe0, 0x80));

binmode STDOUT;
print $im->png;

SEE ALSO

None

AUTHOR

Kazuyoshi Tomita, <kztomita@bit-hive.com>

COPYRIGHT AND LICENSE

Copyright (C) 2007 by Kazuyoshi Tomita

This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself, either Perl version 5.8.6 or, at your option, any later version of Perl 5 you may have available.