org.locationtech.jts.geomgraph

Class EdgeEnd

java.lang.Object

org.locationtech.jts.geomgraph.EdgeEnd

All Implemented Interfaces:

Comparable

Direct Known Subclasses:

DirectedEdge, EdgeEndBundle

public class EdgeEnd
extends Object
implements Comparable

Models the end of an edge incident on a node. EdgeEnds have a direction determined by the direction of the ray from the initial point to the next point. EdgeEnds are comparable under the ordering "a has a greater angle with the x-axis than b". This ordering is used to sort EdgeEnds around a node.

Version:

1.7

Constructor Summary

Constructors

Constructor and Description
EdgeEnd(Edge edge, Coordinate p0, Coordinate p1)
EdgeEnd(Edge edge, Coordinate p0, Coordinate p1, Label label)

Method Summary

Modifier and Type	Method and Description
int	compareDirection(EdgeEnd e) Implements the total order relation:
int	compareTo(Object obj)
void	computeLabel(BoundaryNodeRule boundaryNodeRule)
Coordinate	getCoordinate()
Coordinate	getDirectedCoordinate()
double	getDx()
double	getDy()
Edge	getEdge()
Label	getLabel()
Node	getNode()
int	getQuadrant()
void	print(PrintStream out)
void	setNode(Node node)
String	toString()

Methods inherited from class java.lang.Object

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

Constructor Detail

EdgeEnd

public EdgeEnd(Edge edge,
               Coordinate p0,
               Coordinate p1)

EdgeEnd

public EdgeEnd(Edge edge,
               Coordinate p0,
               Coordinate p1,
               Label label)

Method Detail

getEdge

public Edge getEdge()

getLabel

public Label getLabel()

getCoordinate

public Coordinate getCoordinate()

getDirectedCoordinate

public Coordinate getDirectedCoordinate()

getQuadrant

public int getQuadrant()

getDx

public double getDx()

getDy

public double getDy()

setNode

public void setNode(Node node)

getNode

public Node getNode()

compareTo

public int compareTo(Object obj)

Specified by:

compareTo in interface Comparable

compareDirection

public int compareDirection(EdgeEnd e)

Implements the total order relation:

a has a greater angle with the positive x-axis than b

Using the obvious algorithm of simply computing the angle is not robust, since the angle calculation is obviously susceptible to roundoff. A robust algorithm is: - first compare the quadrant. If the quadrants are different, it it trivial to determine which vector is "greater". - if the vectors lie in the same quadrant, the computeOrientation function can be used to decide the relative orientation of the vectors.

Parameters:

e - EdgeEnd

Returns:

direction comparison

computeLabel

public void computeLabel(BoundaryNodeRule boundaryNodeRule)

print

public void print(PrintStream out)

toString

public String toString()

Overrides:

toString in class Object