jumbo.euclid
Class Real2

java.lang.Object
  |
  +--jumbo.euclid.Status
        |
        +--jumbo.euclid.Real2

Direct Known Subclasses:

Complex, Coordinate2, Vector2

public class Real2

extends Status

Real2 - a pair of FPt numbers - no other assumptions

Contains two doubles. Can be used as-is, but there are some specialised derived classes (e.g. Complex (a complex number), Point2 (x,y coords), etc),

The default value is 0.0, 0.0.

Field Summary

double	x the first floating point value
double	y the second floating point value

Constructor Summary

Real2()

Real2(double x, double y)

Real2(Real2 r)
copy constructor

Method Summary

static Real2[]	addPolygonOnLine(Real2 point1, Real2 point2, int nPoints, int end, Real2 repelPoint) creates a polygon (returns points[]) from two points.
void	clear() set to 0, 0
double	dotProduct(Real2 r) get dot product
double	elementAt(int elem) get either value; counts from ZERO
boolean	equals(Real2 r)
double	getAngle() get angle between origin and this point (i.e polar coords) - uses atan2 (i.e.
static Angle	getAngle(Real2 p1, Real2 p2, Real2 p3) get angle between 3 Real2s (the second is in the centre).
double	getLength() get length of Real2 if centered on origin
Real2	getMidPoint(Real2 p) point midway between 'this' and 'p'
Real2	getUnitVector() get unit vector
double	getX() get X value
double	getY() get Y value
Real2	makePoint(double rad, double theta) make a new point at (dist, theta) from this
Real2	multiplyBy(double f) multiply a point by a scalar
void	negative() multiply both components by -1; MODIFIES 'this'
Real2	plus(Real2 r2) add two points - vector sum;
void	setX(double xx)
void	setY(double yy)
void	sortAscending() sorts x and y so that x <= y
void	sortDescending() sorts x and y so that x >= y
Real2	subtract(Real2 r2) subtract two points - vector difference;
void	swap() swaps the x and y values
java.lang.String	toString()
void	transformBy(Transform2 t) transforms the point by a rot-trans matrix; MODIFIES 'this'

Methods inherited from class jumbo.euclid.Status

NYI

Methods inherited from class java.lang.Object

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

Field Detail

x

public double x

the first floating point value

y

public double y

the second floating point value

Constructor Detail

Real2

public Real2()

Real2

public Real2(double x,
             double y)

Real2

public Real2(Real2 r)

copy constructor

Method Detail

swap

public void swap()

swaps the x and y values

sortAscending

public void sortAscending()

sorts x and y so that x <= y

sortDescending

public void sortDescending()

sorts x and y so that x >= y

clear

public void clear()

set to 0, 0

setX

public void setX(double xx)

setY

public void setY(double yy)

equals

public boolean equals(Real2 r)

plus

public Real2 plus(Real2 r2)

add two points - vector sum;

subtract

public Real2 subtract(Real2 r2)

subtract two points - vector difference;

negative

public void negative()

multiply both components by -1; MODIFIES 'this'

multiplyBy

public Real2 multiplyBy(double f)

multiply a point by a scalar

getX

public double getX()

get X value

getY

public double getY()

get Y value

elementAt

public double elementAt(int elem)
                 throws java.lang.ArrayIndexOutOfBoundsException

get either value; counts from ZERO

getLength

public double getLength()

get length of Real2 if centered on origin

getMidPoint

public Real2 getMidPoint(Real2 p)

point midway between 'this' and 'p'

getUnitVector

public Real2 getUnitVector()
                    throws ZeroVectorException

get unit vector

Throws:

ZeroVectorException - this was of zero length

dotProduct

public double dotProduct(Real2 r)

get dot product

getAngle

public static Angle getAngle(Real2 p1,
                             Real2 p2,
                             Real2 p3)

get angle between 3 Real2s (the second is in the centre). angle is CLOCKWISE from p1 to p3

transformBy

public void transformBy(Transform2 t)

transforms the point by a rot-trans matrix; MODIFIES 'this'

addPolygonOnLine

public static Real2[] addPolygonOnLine(Real2 point1,
                                       Real2 point2,
                                       int nPoints,
                                       int end,
                                       Real2 repelPoint)

creates a polygon (returns points[]) from two points. Serial numbers of points are 0 and end (i.e. point1 is points[0] and point2 is points[end]. if end == 0, end=>1

getAngle

public double getAngle()

get angle between origin and this point (i.e polar coords) - uses atan2 (i.e. anticlockwise from X axis); if x == y == 0.0 presumably returns NaN

makePoint

public Real2 makePoint(double rad,
                       double theta)

make a new point at (dist, theta) from this

Parameters:

double - rad the distance to new point

double - angle the angle to new point (anticlockwise from X axis), i.e. theta=0 gives (rad, 0), theta=PI/2 gives (0, rad)

Returns:

Real2 new point

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object