org.locationtech.jts.algorithm

Class ConvexHull.RadialComparator

java.lang.Object

org.locationtech.jts.algorithm.ConvexHull.RadialComparator

All Implemented Interfaces:

java.util.Comparator

Enclosing class:

ConvexHull

private static class ConvexHull.RadialComparator
extends java.lang.Object
implements java.util.Comparator

Compares Coordinates for their angle and distance relative to an origin.

Version:

1.7

Field Summary

Fields

Modifier and Type	Field and Description
private Coordinate	origin

Constructor Summary

Constructors

Constructor and Description
RadialComparator(Coordinate origin)

Method Summary

Modifier and Type	Method and Description
int	compare(java.lang.Object o1, java.lang.Object o2)
private static int	polarCompare(Coordinate o, Coordinate p, Coordinate q) Given two points p and q compare them with respect to their radial ordering about point o.

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.util.Comparator

comparing, comparing, comparingDouble, comparingInt, comparingLong, equals, naturalOrder, nullsFirst, nullsLast, reversed, reverseOrder, thenComparing, thenComparing, thenComparing, thenComparingDouble, thenComparingInt, thenComparingLong

Field Detail

origin

private Coordinate origin

Constructor Detail

RadialComparator

public RadialComparator(Coordinate origin)

Method Detail

compare

public int compare(java.lang.Object o1,
                   java.lang.Object o2)

Specified by:

compare in interface java.util.Comparator

polarCompare

private static int polarCompare(Coordinate o,
                                Coordinate p,
                                Coordinate q)

Given two points p and q compare them with respect to their radial ordering about point o. First checks radial ordering. If points are collinear, the comparison is based on their distance to the origin.

p < q iff

• ang(o-p) < ang(o-q) (e.g. o-p-q is CCW)
• or ang(o-p) == ang(o-q) && dist(o,p) < dist(o,q)

Parameters:

o - the origin

p - a point

q - another point

Returns:

-1, 0 or 1 depending on whether p is less than, equal to or greater than q