EE324StandardProjectClasses

Class TestPolygonGenerator

java.lang.Object

EE324StandardProjectClasses.TestPolygonGenerator

public class TestPolygonGenerator
extends java.lang.Object

A set of static methods for generating different types of test polygons.

These methods will be useful for testing your hull finding algorithm. Each method returns a polygon, as an array of Point2D objects. Note that polygons are "open" (first point not repeated as last point in array).

Rounding is applied to point coordinate values to avoid potential floating-point rounding issues. (This helps eliminate precision problems when using these generated polygons with the JTS library (or your own geometry algorithms). See: https://locationtech.github.io/jts/jts-faq.html#robustness Section D).

Author:

Conor McArdle (conor.mcardle@dcu.ie)

Constructor Summary

Constructors

Constructor and Description
TestPolygonGenerator()

Method Summary

Modifier and Type	Method and Description
static Point2D[]	collinear1() Makes a 10 point polygon that contains some collinear points (pattern 1)
static Point2D[]	collinear2() Makes a 10 point polygon that contains some collinear points (pattern 2)
static Point2D[]	randomPolyGaussian(int size) Make a random set of points normally-distributed and centered on point (0.5,0.5).
static Point2D[]	randomPolyUniform(int size) Make a random set of points uniformly distributed within the unit square from (0,0) to (1,1).

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

TestPolygonGenerator

public TestPolygonGenerator()

Method Detail

collinear1

public static Point2D[] collinear1()

Makes a 10 point polygon that contains some collinear points (pattern 1)

Returns:

the points of the polygon as an array of Point2D

collinear2

public static Point2D[] collinear2()

Makes a 10 point polygon that contains some collinear points (pattern 2)

Returns:

the points of the polygon as an array of Point2D

randomPolyGaussian

public static Point2D[] randomPolyGaussian(int size)

Make a random set of points normally-distributed and centered on point (0.5,0.5). Variance of distribution is set so that points are likely to remain with the unit square from (0,0) to (1,1). Precision of point coordinates is limited to 4 places of decimals.

Parameters:

size - number of points in generated polygon

Returns:

the points of the polygon as an array of Point2D

Throws:

java.lang.IllegalArgumentException - if size is less than 3

randomPolyUniform

public static Point2D[] randomPolyUniform(int size)

Make a random set of points uniformly distributed within the unit square from (0,0) to (1,1). Precision of point coordinates is limited to 4 places of decimals.

Parameters:

size - number of point in generated polygon

Returns:

the points of the polygon, as an array of Point2D

Throws:

java.lang.IllegalArgumentException - if size is less than 3