math.geom2d
Class Vector2D

java.lang.Object
  math.geom2d.Vector2D

public class Vector2D
extends java.lang.Object

Define a vector in 2 Dimensions. Provides methods to compute cross product and dot product, addition and subtraction of vectors.

Field Summary

protected double	dx
protected double	dy

Constructor Summary

Vector2D()
construct a new Vectors initialized with dx=1 and dy=0.

Vector2D(double dx, double dy)
constructor with given position.

Vector2D(java.awt.geom.Point2D point)
construct a new vector between origin and the point.

Vector2D(java.awt.geom.Point2D point1, java.awt.geom.Point2D point2)
construct a new vector between two points

Method Summary

static Vector2D	createPolar(double rho, double theta)
double	cross(Vector2D v) Get the cross product with point p.
static double	cross(Vector2D v1, Vector2D v2) get the cross product of the two vectors, defined by : dx1*dy2 - dx2*dy1 cross product is zero for colinear vectors.
double	dot(Vector2D v) Get the dot product with point p.
static double	dot(Vector2D v1, Vector2D v2) Get the dot product of the two vectors, defined by : dx1*dy2 + dx2*dy1 Dot product is zero if the vectors defined by the 2 vectors are orthogonal.
boolean	equals(java.lang.Object obj) Test whether this object is the same as another vector.
double	getAngle() Returns the angle with the horizontal axis, in radians.
double	getDx()
double	getDy()
double	getNorm() Computes the norm of the vector
Vector2D	getNormalizedVector() Returns the vector with same direction as this one, but with norm equal to 1.
Vector2D	getOpposite() Returns the opposite vector v2 of this, such that the sum of this and v2 equals the null vector.
boolean	isColinear(Vector2D v) test if the two vectors are colinear
static boolean	isColinear(Vector2D v1, Vector2D v2) test if the two vectors are colinear
boolean	isOrthogonal(Vector2D v) test if the two vectors are orthogonal
static boolean	isOrthogonal(Vector2D v1, Vector2D v2) test if the two vectors are orthogonal
Vector2D	minus(Vector2D v) Return the subtraction of current vector with vector given as parameter.
void	normalize() Normalizes the vector, such that its norms becomes 1.
Vector2D	plus(Vector2D v) Return the sum of current vector with vector given as parameter.
void	setAsPolar(double rho, double theta) Set location specified as polar coordinate : distance from origin + angle with horizontal.
void	setDx(double dx)
void	setDy(double dy)
void	setVector(double dx, double dy)
Vector2D	transform(AffineTransform2D trans) Transform the vector, by using only the first 4 parameters of the transform.

Methods inherited from class java.lang.Object

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

Field Detail

dx

protected double dx

dy

protected double dy

Constructor Detail

Vector2D

public Vector2D()

construct a new Vectors initialized with dx=1 and dy=0.

Vector2D

public Vector2D(java.awt.geom.Point2D point)

construct a new vector between origin and the point.

Vector2D

public Vector2D(java.awt.geom.Point2D point1,
                java.awt.geom.Point2D point2)

construct a new vector between two points

Vector2D

public Vector2D(double dx,
                double dy)

constructor with given position.

Method Detail

createPolar

public static final Vector2D createPolar(double rho,
                                         double theta)

dot

public static final double dot(Vector2D v1,
                               Vector2D v2)

Get the dot product of the two vectors, defined by :

dx1*dy2 + dx2*dy1

Dot product is zero if the vectors defined by the 2 vectors are orthogonal. It is positive if vectors are in the same direction, and negative if they are in opposite direction.

cross

public static final double cross(Vector2D v1,
                                 Vector2D v2)

get the cross product of the two vectors, defined by :

dx1*dy2 - dx2*dy1

cross product is zero for colinear vectors. It is positive if angle between vector 1 and vector 2 is comprised between 0 and PI, and negative otherwise.

isColinear

public static final boolean isColinear(Vector2D v1,
                                       Vector2D v2)

test if the two vectors are colinear

Returns:

true if the vectors are colinear

isOrthogonal

public static final boolean isOrthogonal(Vector2D v1,
                                         Vector2D v2)

test if the two vectors are orthogonal

Returns:

true if the vectors are orthogonal

getDx

public double getDx()

getDy

public double getDy()

setDx

public void setDx(double dx)

setDy

public void setDy(double dy)

setVector

public void setVector(double dx,
                      double dy)

setAsPolar

public void setAsPolar(double rho,
                       double theta)

Set location specified as polar coordinate : distance from origin + angle with horizontal.

getOpposite

public Vector2D getOpposite()

Returns the opposite vector v2 of this, such that the sum of this and v2 equals the null vector.

Returns:

the vector opposite to this.

getNorm

public double getNorm()

Computes the norm of the vector

Returns:

the euclidean norm of the vector

getAngle

public double getAngle()

Returns the angle with the horizontal axis, in radians.

Returns:

the horizontal angle

normalize

public void normalize()

Normalizes the vector, such that its norms becomes 1.

getNormalizedVector

public Vector2D getNormalizedVector()

Returns the vector with same direction as this one, but with norm equal to 1.

isColinear

public boolean isColinear(Vector2D v)

test if the two vectors are colinear

Returns:

true if the vectors are colinear

isOrthogonal

public boolean isOrthogonal(Vector2D v)

test if the two vectors are orthogonal

Returns:

true if the vectors are orthogonal

dot

public double dot(Vector2D v)

Get the dot product with point p. Dot product id defined by :

x1*y2 + x2*y1

Dot product is zero if the vectors defined by the 2 points are orthogonal. It is positive if vectors are in the same direction, and negative if they are in opposite direction.

cross

public double cross(Vector2D v)

Get the cross product with point p. Cross product is defined by :

x1*y2 - x2*y1

cross product is zero for colinear vector. It is positive if angle between vector 1 and vector 2 is comprised between 0 and PI, and negative otherwise.

plus

public Vector2D plus(Vector2D v)

Return the sum of current vector with vector given as parameter. Inner fields are not modified.

minus

public Vector2D minus(Vector2D v)

Return the subtraction of current vector with vector given as parameter. Inner fields are not modified.

transform

public Vector2D transform(AffineTransform2D trans)

Transform the vector, by using only the first 4 parameters of the transform. Translation of a vector returns the same vector.

Parameters:

trans - an affine transform

Returns:

the transformed vector.

equals

public boolean equals(java.lang.Object obj)

Test whether this object is the same as another vector.

Overrides:

equals in class java.lang.Object