Direction2D

java.lang.Object
- net.algart.math.geom.Direction2D

All Implemented Interfaces:

java.lang.Cloneable
```
public class Direction2D
extends java.lang.Object
implements java.lang.Cloneable
```
2D direction: an angle φ + corresponding unit vector (cos φ, sin φ)

This class is immutable and thread-safe: there are no ways to modify settings of the created instance.

AlgART Laboratory 2007–2014

Since:

JDK 1.0

Version:

1.0

Author:

Daniel Alievsky

Method Summary

Methods
Modifier and Type	Method and Description
`java.lang.Object`	`clone()` Creates an identical copy of this object.
`void`	`copyFrom(Direction2D other)` Sets the current direction identical to `other`.
`boolean`	`equals(java.lang.Object obj)` Indicates whether some other direction is equal to this one, i.e. if the angle returned by `getAngle()` is the same for both directions.
`double`	`getAngle()` Returns the angle: current direction is (cos φ, sin φ), φ = method result (in radians).
`double`	`getAngleBetweenDirections(Direction2D other)` Returns the shortes angle (0..π, in radians) between the given directions.
`static Direction2D`	`getInstance()` Creates a direction (1, 0), φ = 0.
`static Direction2D`	`getInstance(double fi)` Creates a direction (cos φ, sin φ), φ = `fi` argument (in radians).
`double`	`getUnitVectorX()` Returns cos φ, current direction is (cos φ, sin φ).
`double`	`getUnitVectorY()` Returns sin φ, current direction is (cos φ, sin φ).
`int`	`hashCode()` Returns the hash code for this direction.
`void`	`inverse()` Rotates current direction by π: new direction angle will be φ + π, where φ is current direction angle.
`void`	`revive()` Revive direction vector: the direction angle φ is changed to an equivalent angle in 0<=φ<2π range (if current φ is not in this range), and the values cos φ and sin φ are recalculated.
`void`	`rotate(Rotation2D rot)` Rotates current direction: new direction angle will be φ + rot.getRotationAngle(), where φ is current direction angle.
`void`	`rotateBack(Rotation2D rot)` Rotates current direction: new direction angle will be φ - rot.getRotationAngle(), where φ is current direction angle.
`void`	`setAngle(double fi)` Sets the angle: new direction will be (cos φ, sin φ), φ = `fi` argument (in radians).
`java.lang.String`	`toString()` Returns some string representation of this object.

Methods inherited from class java.lang.Object
finalize, getClass, notify, notifyAll, wait, wait, wait

- Method Detail
  - getInstance
```
public static Direction2D getInstance()
```
    Creates a direction (1, 0), φ = 0.
  - getInstance
```
public static Direction2D getInstance(double fi)
```
    Creates a direction (cos φ, sin φ), φ = fi argument (in radians).
  - setAngle
```
public void setAngle(double fi)
```
    Sets the angle: new direction will be (cos φ, sin φ), φ = fi argument (in radians).
  - getAngle
```
public double getAngle()
```
    Returns the angle: current direction is (cos φ, sin φ), φ = method result (in radians).
  - getUnitVectorX
```
public double getUnitVectorX()
```
    Returns cos φ, current direction is (cos φ, sin φ).
  - getUnitVectorY
```
public double getUnitVectorY()
```
    Returns sin φ, current direction is (cos φ, sin φ).
  - getAngleBetweenDirections
```
public double getAngleBetweenDirections(Direction2D other)
```
    Returns the shortes angle (0..π, in radians) between the given directions.
  - revive
```
public void revive()
```
    Revive direction vector: the direction angle φ is changed to an equivalent angle in 0<=φ<2π range (if current φ is not in this range), and the values cos φ and sin φ are recalculated. This method should be called sometimes in any long sequence of rotate or rotateBack methods.
  - rotate
```
public void rotate(Rotation2D rot)
```
    Rotates current direction: new direction angle will be φ + rot.getRotationAngle(), where φ is current direction angle.
  - rotateBack
```
public void rotateBack(Rotation2D rot)
```
    Rotates current direction: new direction angle will be φ - rot.getRotationAngle(), where φ is current direction angle.
  - inverse
```
public void inverse()
```
    Rotates current direction by π: new direction angle will be φ + π, where φ is current direction angle.
  - copyFrom
```
public void copyFrom(Direction2D other)
```
    Sets the current direction identical to other.
  - toString
```
public java.lang.String toString()
```
    Returns some string representation of this object.
    
    Overrides:
    
    toString in class java.lang.Object
  - hashCode
```
public int hashCode()
```
    Returns the hash code for this direction.
    
    Overrides:
    
    hashCode in class java.lang.Object
  - equals
```
public boolean equals(java.lang.Object obj)
```
    Indicates whether some other direction is equal to this one, i.e. if the angle returned by getAngle() is the same for both directions.
    Note: if the difference between directions is 2kπ, the directions are not considered to be equal, though their unit vector are identical.
    
    Overrides:
    
    equals in class java.lang.Object
  - clone
```
public java.lang.Object clone()
```
    Creates an identical copy of this object.
    
    Overrides:
    
    clone in class java.lang.Object

Class Direction2D

Method Summary

Methods inherited from class java.lang.Object

Method Detail

getInstance

getInstance

setAngle

getAngle

getUnitVectorX

getUnitVectorY

getAngleBetweenDirections

revive

rotate

rotateBack

inverse

copyFrom

toString

hashCode

equals

clone