org.girod.javafx.svgimage.fromjfx.awt.utils

Class Vector2D

java.lang.Object

org.girod.javafx.svgimage.fromjfx.awt.utils.Vector2D

All Implemented Interfaces:

java.lang.Cloneable

public class Vector2D
extends java.lang.Object
implements java.lang.Cloneable

This class represents a 2D Vector. It offers several utility methods to manage vectors :

• normalization, angle, product of a vector by a scalar
• rotation of a vector, perpendicular vector
• addition, soustraction, scalar product of two vectors
• intersection between two lines defined by a point and a vector
• projection of a point on a line defined by this vector and an origin point
• determination if two lines are colinear
• result of an affine transformation

Since:

1.8

Field Summary

Fields

Modifier and Type	Field and Description
static double	ASSUME_ANGLE_ZERO 0.017: Constant used for angles equality.
static double	ASSUME_ZERO 1.0E-4: Constant used for coordinates equality.
double	x The x coordinate of the Vector.
double	y The y coordinate of the Vector.

Constructor Summary

Constructors

Constructor and Description
Vector2D() Create a (0, 0) 2D Vector.
Vector2D(double x, double y) Create a 2D Vector, knowing its x and y coordinates.
Vector2D(java.awt.geom.Point2D p0, java.awt.geom.Point2D p1) Create a 2D Vector, knowing its two associated points.
Vector2D(Vector2D v) Create a 2D Vector, identical to another Vector2D.

Method Summary

Modifier and Type	Method and Description
Vector2D	add(Vector2D v) Adds another Vector to this one.
java.lang.Object	clone()
double	getAngle() Return the angle of this vector with the X axis.
java.awt.geom.Point2D	getIntersection(java.awt.geom.Point2D p0, Vector2D v1, java.awt.geom.Point2D p1) Find the intersection between two lines.
Vector2D	getInverse() Return the inverse of this Vector, which is this vector rotated by PI.
double	getNorm() Return the euclidian norm of this Vector.
Vector2D	getNormal() Return the normal of this vector.
java.awt.geom.Point2D	getNormalProjection(java.awt.geom.Point2D o, java.awt.geom.Point2D p) Return the orthogonal projection of this point on the line defined by the Vector2D.
double	getScalarProduct(Vector2D v) Return the scalar product of this vector with another vector.
double	getX() Return the X coordinate of this Vector.
double	getY() Return the Y coordinate of this Vector.
boolean	isColinear(java.awt.geom.Point2D p0, Vector2D v1, java.awt.geom.Point2D p1) Determines if two lines are colinear.
boolean	isColinear(java.awt.geom.Point2D p0, Vector2D v1, java.awt.geom.Point2D p1, double delta, double deltaAngle) Determines if two lines are colinear.
Vector2D	minus(Vector2D v) Substracts another vector from this one.
Vector2D	normalize() Normalize this vector.
Vector2D	rotate(double alpha) Rotates the Vector.
Vector2D	scaleTo(double d) Multiply the coordinates of this Vector by a scalar value.
void	setX(double x) Set the X coordinate of this Vector.
void	setY(double y) Set the Y coordinate of this Vector.
Vector2D	transform(java.awt.geom.AffineTransform tr) Return the Vector2D after an AffineTransform.
static java.awt.geom.Point2D	transform(java.awt.geom.Point2D p, java.awt.geom.AffineTransform tr) Return a Point2D transformed after an affine transformation.
java.awt.geom.Point2D	translate(java.awt.geom.Point2D p) Translate a Point by this vector.

Methods inherited from class java.lang.Object

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

Field Detail

x

public double x

The x coordinate of the Vector.

y

public double y

The y coordinate of the Vector.

ASSUME_ZERO

public static final double ASSUME_ZERO

1.0E-4: Constant used for coordinates equality. Its value is 0.0001.

See Also:

Constant Field Values

ASSUME_ANGLE_ZERO

public static final double ASSUME_ANGLE_ZERO

0.017: Constant used for angles equality. Its value is approximately equal to 1 degree expressed in radians (0.017 radians).

See Also:

Constant Field Values

Constructor Detail

Vector2D

public Vector2D()

Create a (0, 0) 2D Vector.

Vector2D

public Vector2D(double x,
                double y)

Create a 2D Vector, knowing its x and y coordinates.

Parameters:

x - the x coordinate

y - the y coordinate

Vector2D

public Vector2D(java.awt.geom.Point2D p0,
                java.awt.geom.Point2D p1)

Create a 2D Vector, knowing its two associated points.

Parameters:

p0 - the first point

p1 - the second point

Vector2D

public Vector2D(Vector2D v)

Create a 2D Vector, identical to another Vector2D.

Parameters:

v - the vector to clone

Method Detail

getX

public double getX()

Return the X coordinate of this Vector.

Returns:

the X coordinate

getY

public double getY()

Return the Y coordinate of this Vector.

Returns:

the Y coordinate

setX

public void setX(double x)

Set the X coordinate of this Vector.

Parameters:

x - the X coordinate

setY

public void setY(double y)

Set the Y coordinate of this Vector.

Parameters:

y - the Y coordinate

getScalarProduct

public double getScalarProduct(Vector2D v)

Return the scalar product of this vector with another vector.

Parameters:

v - the other Vector

Returns:

the scalar product

minus

public Vector2D minus(Vector2D v)

Substracts another vector from this one.

Parameters:

v - the other Vector

Returns:

a new vector which is the result of the substraction

rotate

public Vector2D rotate(double alpha)

Rotates the Vector.

Parameters:

alpha - the angle in Radians

Returns:

a new vector which is the result of the rotation

add

public Vector2D add(Vector2D v)

Adds another Vector to this one.

Parameters:

v - the other Vector

Returns:

a new Vector which is the result of the addition

getNorm

public double getNorm()

Return the euclidian norm of this Vector.

Returns:

the euclidian norm of this Vector

getAngle

public double getAngle()

Return the angle of this vector with the X axis. The angle is in the range of -pi to pi (using Math.atan2 formula)

Returns:

the angle in Radians

normalize

public Vector2D normalize()

Normalize this vector. If this vector has a zero norm, then the normalized vector will be the (0, 0) vector.

Returns:

a new vector which is the result of the normalization

scaleTo

public Vector2D scaleTo(double d)

Multiply the coordinates of this Vector by a scalar value.

Parameters:

d - the factor

Returns:

a new Vector which is the result of the multiplication

translate

public java.awt.geom.Point2D translate(java.awt.geom.Point2D p)

Translate a Point by this vector.

Parameters:

p - the Point

Returns:

the translated Point

getNormal

public Vector2D getNormal()

Return the normal of this vector. If this vector has a zero norm, then the normal will be the (0, 0) vector, else it will have a unit norm.

Returns:

the normal Vector

getInverse

public Vector2D getInverse()

Return the inverse of this Vector, which is this vector rotated by PI.

Returns:

the inverse of this Vector

getNormalProjection

public java.awt.geom.Point2D getNormalProjection(java.awt.geom.Point2D o,
                                                 java.awt.geom.Point2D p)

Return the orthogonal projection of this point on the line defined by the Vector2D. If this vector has a zero norm, then the projection will be the initial point.

Parameters:

o - the origin of the line

p - the point to project

Returns:

the orthogonal projection of p

isColinear

public boolean isColinear(java.awt.geom.Point2D p0,
                          Vector2D v1,
                          java.awt.geom.Point2D p1,
                          double delta,
                          double deltaAngle)

Determines if two lines are colinear. The two lines are :

• the line defined by the point p0 and this Vector2D
• the line defined by the point p1 and the Vector2D v1

The two lines are considered colinear if :

• the distance between the projection of p1 on the line defined by p0 and this Vector2D, and the point p1, is less than delta
• the difference between the angles of the two vectors are less than delta_angle

Parameters:

p0 - origin of the first line (defined by this vector)

v1 - vector defining the second line

p1 - origin of the second line

delta - the delta concerning the distance of p1 to the first line

deltaAngle - the delta concerning the difference between the two angles

Returns:

true if the two lines are colinear

isColinear

public boolean isColinear(java.awt.geom.Point2D p0,
                          Vector2D v1,
                          java.awt.geom.Point2D p1)

Determines if two lines are colinear.

Same as {link #isColinear(Point2D, Vector2D, Point2D, double, double)} where :

• the delta parameter is equal to ASSUME_ZERO
• the delta_angle parameter is equal to ASSUME_ANGLE_ZERO

Parameters:

p0 - origin of the first line (defined by this vector)

v1 - vector defining the second line

p1 - origin of the second line

Returns:

true if the two lines are colinear

getIntersection

public java.awt.geom.Point2D getIntersection(java.awt.geom.Point2D p0,
                                             Vector2D v1,
                                             java.awt.geom.Point2D p1)

Find the intersection between two lines. The two lines are:

• the line defined by the point p0 and this Vector2D
• the line defined by the point p1 and the Vector2D v1

It is considered that there is no intersection if either :

• the two x coordinates are closer from 0 than the ASSUME_ZERO value
• the two x coordinates are farther from 0 than the ASSUME_ZERO value, but they differ from less than this value

Remark: The intersection is computed by resolving the following equations:

• y = a0 * x + b0
• y = a1 * x + b1

where :

• the first (a0, b0) line is defined by this Vector2D and the point p0
• the second (a1, b1) line is defined by the Vector2D v1 and the point p1

Parameters:

p0 - origin of the first line (defined by this vector)

v1 - vector defining the second line

p1 - origin of the second line

Returns:

the intersection Point

clone

public java.lang.Object clone()

Overrides:

clone in class java.lang.Object

transform

public Vector2D transform(java.awt.geom.AffineTransform tr)

Return the Vector2D after an AffineTransform.

Parameters:

tr - the AffineTransform

Returns:

a new Vector2D which is the result of the AffineTransform by tr

transform

public static java.awt.geom.Point2D transform(java.awt.geom.Point2D p,
                                              java.awt.geom.AffineTransform tr)

Return a Point2D transformed after an affine transformation.

Parameters:

p - the point

tr - the AffineTransform

Returns:

a Point2D which is the result of the AffineTransform of p by tr