Package org.locationtech.jts.algorithm

Class CGAlgorithmsDD

java.lang.Object

org.locationtech.jts.algorithm.CGAlgorithmsDD

public class CGAlgorithmsDD
extends Object

Implements basic computational geometry algorithms using DD arithmetic.

Author:

Martin Davis

Method Summary

Modifier and Type	Method	Description
static Coordinate	intersection(Coordinate p1, Coordinate p2, Coordinate q1, Coordinate q2)	Computes an intersection point between two lines using DD arithmetic.
static int	orientationIndex(Coordinate p1, Coordinate p2, Coordinate q)	Returns the index of the direction of the point q relative to a vector specified by p1-p2.
static int	signOfDet2x2(double dx1, double dy1, double dx2, double dy2)	Computes the sign of the determinant of the 2x2 matrix with the given entries.
static int	signOfDet2x2(DD x1, DD y1, DD x2, DD y2)	Computes the sign of the determinant of the 2x2 matrix with the given entries.

Methods inherited from class java.lang.Object

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

Method Detail

orientationIndex

public static int orientationIndex(Coordinate p1,
                                   Coordinate p2,
                                   Coordinate q)

Returns the index of the direction of the point q relative to a vector specified by p1-p2.

Parameters:

p1 - the origin point of the vector

p2 - the final point of the vector

q - the point to compute the direction to

Returns:

1 if q is counter-clockwise (left) from p1-p2

signOfDet2x2

public static int signOfDet2x2(DD x1,
                               DD y1,
                               DD x2,
                               DD y2)

Computes the sign of the determinant of the 2x2 matrix with the given entries.

Returns:

-1 if the determinant is negative,

signOfDet2x2

public static int signOfDet2x2(double dx1,
                               double dy1,
                               double dx2,
                               double dy2)

Computes the sign of the determinant of the 2x2 matrix with the given entries.

Returns:

-1 if the determinant is negative,

intersection

public static Coordinate intersection(Coordinate p1,
                                      Coordinate p2,
                                      Coordinate q1,
                                      Coordinate q2)

Computes an intersection point between two lines using DD arithmetic. Currently does not handle case of parallel lines.

Parameters:

p1 -

p2 -

q1 -

q2 -

Returns:

an intersection point if one exists