lejos.robotics.geometry

Class Line2D

java.lang.Object

lejos.robotics.geometry.Line2D

All Implemented Interfaces:

java.lang.Cloneable, Shape

Direct Known Subclasses:

Line2D.Double, Line2D.Float

public abstract class Line2D
extends java.lang.Object
implements Shape, java.lang.Cloneable

An abstract class representing a line in two dimensional space

Author:

Lawrie Griffiths

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	Line2D.Double A line in 2D space using float coordinates
static class	Line2D.Float A line in 2D space using float coordinates

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	Line2D() This is an abstract class that cannot be instantiated: use Line2D.Float or Line2D.Double.

Method Summary

Modifier and Type	Method and Description
java.lang.Object	clone()
boolean	contains(double x, double y) Test if the shape contains the point (x,y)
boolean	contains(double x, double y, double w, double h) Test if the shape contains the rectangle with top left at (x,y), width w and height h.
boolean	contains(Point2D p) Test if the shape contains the Point2D
boolean	contains(Rectangle2D r) Test if the shape contains the Rectangle2D
RectangleInt32	getBounds() Get the bounding Rectangle for the shape
abstract Point2D	getP1() Get the start point of the line as a Point2D
abstract Point2D	getP2() Get the end point of the line as a Point2D
abstract double	getX1() Get the x coordinate of the start of the line
abstract double	getX2() Get the x coordinate of the end of the line
abstract double	getY1() Get the y coordinate of the start of the line
abstract double	getY2() Get the y coordinate of the end of the line
boolean	intersects(double x, double y, double w, double h) Test if the shape intersects the rectangle with top left at (x,y), width w and height h.
boolean	intersects(Rectangle2D r) Test if the shape intersects the Rectangle2D r
boolean	intersectsLine(double x1, double y1, double x2, double y2) Test if this line intersects a given line
boolean	intersectsLine(Line2D l) Tests if this line intersects a given line
static boolean	linesIntersect(double x1, double y1, double x2, double y2, double x3, double y3, double x4, double y4) Test if one line intersects another line
double	ptSegDist(double px, double py) Measures the shortest distance from the reference point to a point on this line segment.
static double	ptSegDist(double x1, double y1, double x2, double y2, double px, double py) Measures the shortest distance from the reference point to a point on the line segment.
double	ptSegDist(Point2D p) Measures the shortest distance from the reference point to a point on this line segment.
double	ptSegDistSq(double px, double py) Measures the square of the shortest distance from the reference point to a point on this line segment.
static double	ptSegDistSq(double x1, double y1, double x2, double y2, double px, double py) Measures the square of the shortest distance from the reference point to a point on the line segment.
double	ptSegDistSq(Point2D p) Measures the square of the shortest distance from the reference point to a point on this line segment.
int	relativeCCW(double px, double py) Returns an indicator of where the specified point lies with respect to the line.
static int	relativeCCW(double x1, double y1, double x2, double y2, double px, double py) Returns an indicator of where the specified point lies with respect to the line
int	relativeCCW(Point2D p) Returns an indicator of where the specified point lies with respect to the line
abstract void	setLine(double x1, double y1, double x2, double y2) Sets the end points of the line using double coordinates.
void	setLine(Line2D line) Set the end points of a line to the same as a given line
void	setLine(Point2D p1, Point2D p2) Sets the end points of the line from a given start and end point

Methods inherited from class java.lang.Object

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

Methods inherited from interface lejos.robotics.geometry.Shape

getBounds2D

Constructor Detail

Line2D

protected Line2D()

This is an abstract class that cannot be instantiated: use Line2D.Float or Line2D.Double.

Method Detail

getX1

public abstract double getX1()

Get the x coordinate of the start of the line

Returns:

the x coordinate as a double

getY1

public abstract double getY1()

Get the y coordinate of the start of the line

Returns:

the y coordinate as a double

getP1

public abstract Point2D getP1()

Get the start point of the line as a Point2D

Returns:

the Point2D

getX2

public abstract double getX2()

Get the x coordinate of the end of the line

Returns:

the x coordinate as a double

getY2

public abstract double getY2()

Get the y coordinate of the end of the line

Returns:

the y coordinate as a double

getP2

public abstract Point2D getP2()

Get the end point of the line as a Point2D

Returns:

the Point2D

setLine

public abstract void setLine(double x1,
                             double y1,
                             double x2,
                             double y2)

Sets the end points of the line using double coordinates.

Parameters:

x1 - the x coordinate of the start point

y1 - the y coordinate of the start point

x2 - the x coordinate of the end point

y2 - the y coordinate of the end point

setLine

public void setLine(Point2D p1,
                    Point2D p2)

Sets the end points of the line from a given start and end point

Parameters:

p1 - the start point

p2 - the end point

setLine

public void setLine(Line2D line)

Set the end points of a line to the same as a given line

Parameters:

line - the given line

contains

public boolean contains(double x,
                        double y)

Description copied from interface: Shape

Test if the shape contains the point (x,y)

Specified by:

contains in interface Shape

Parameters:

x - the x co-ordinate of the point

y - the y co-ordinate of the point

Returns:

true iff the shape contains the point

contains

public boolean contains(Point2D p)

Description copied from interface: Shape

Test if the shape contains the Point2D

Specified by:

contains in interface Shape

Parameters:

p - the Point2D

Returns:

true iff the shape contains the point

contains

public boolean contains(double x,
                        double y,
                        double w,
                        double h)

Description copied from interface: Shape

Test if the shape contains the rectangle with top left at (x,y), width w and height h.

Specified by:

contains in interface Shape

Parameters:

x - the x-coordinate of the top left point of the rectangle

y - the y-coordinate of the top left point of the rectangle

w - the width of the rectangle

h - the height of the rectangle

Returns:

true iff the shape contains the rectangle

contains

public boolean contains(Rectangle2D r)

Description copied from interface: Shape

Test if the shape contains the Rectangle2D

Specified by:

contains in interface Shape

Parameters:

r - the Rectangle2D

Returns:

true iff the shape contains the Rectangle2D

intersects

public boolean intersects(double x,
                          double y,
                          double w,
                          double h)

Description copied from interface: Shape

Test if the shape intersects the rectangle with top left at (x,y), width w and height h.

Specified by:

intersects in interface Shape

Parameters:

x - the x-coordinate of the top left point of the rectangle

y - the y-coordinate of the top left point of the rectangle

w - the width of the rectangle

h - the height of the rectangle

Returns:

true iff the shape intersects the rectangle

intersectsLine

public boolean intersectsLine(double x1,
                              double y1,
                              double x2,
                              double y2)

Test if this line intersects a given line

Parameters:

x1 - the x coordinate of the start of the given line

y1 - the y coordinate of the start of the given line

x2 - the x coordinate of the end of the given line

y2 - the y coordinate of the end of the given line

Returns:

true iff the lines intersect

intersectsLine

public boolean intersectsLine(Line2D l)

Tests if this line intersects a given line

Parameters:

l - the given line

Returns:

true iff the lines intersect

linesIntersect

public static boolean linesIntersect(double x1,
                                     double y1,
                                     double x2,
                                     double y2,
                                     double x3,
                                     double y3,
                                     double x4,
                                     double y4)

Test if one line intersects another line

Parameters:

x1 - the x coordinate of the start of the first line

y1 - the y coordinate of the start of the first line

x2 - the x coordinate of the end of the first line

y2 - the y coordinate of the end of the first line

x3 - the x coordinate of the start of the second line

y3 - the y coordinate of the start of the second line

x4 - the x coordinate of the end of the second line

y4 - the y coordinate of the end of the second line

Returns:

true iff the lines intersect

getBounds

public RectangleInt32 getBounds()

Description copied from interface: Shape

Get the bounding Rectangle for the shape

Specified by:

getBounds in interface Shape

Returns:

the bounding Rectangle

clone

public java.lang.Object clone()

Overrides:

clone in class java.lang.Object

relativeCCW

public static int relativeCCW(double x1,
                              double y1,
                              double x2,
                              double y2,
                              double px,
                              double py)

Returns an indicator of where the specified point lies with respect to the line

Parameters:

x1 - the x coordinate of the start of the line

y1 - the y coordinate of the start of the line

x2 - the x coordinate of the end of the line

y2 - the y coordinate of the end of the line

px - the x coordinate of the specified point

py - the y coordinate of the specified point

Returns:

0 iff the point is on the line else 1 or -1 depending on whether the point in to the left or ahead of the line, or to the right or behind the line segment

relativeCCW

public int relativeCCW(Point2D p)

Returns an indicator of where the specified point lies with respect to the line

Parameters:

p - the specified point

Returns:

0 iff the point is on the line else 1 or -1 depending on whether the point in to the left or ahead of the line, or to the right or behind the line segment

relativeCCW

public int relativeCCW(double px,
                       double py)

Returns an indicator of where the specified point lies with respect to the line.

Parameters:

px - the x coordinate of the specified point

py - the y coordinate of the specified point

Returns:

0 iff the point is on the line else 1 or -1 depending on whether the point in to the left or ahead of the line, or to the right or behind the line segment

intersects

public boolean intersects(Rectangle2D r)

Description copied from interface: Shape

Test if the shape intersects the Rectangle2D r

Specified by:

intersects in interface Shape

Parameters:

r - the Recangle2D

Returns:

true iff the shape intersects the Rectangle2D

ptSegDistSq

public static double ptSegDistSq(double x1,
                                 double y1,
                                 double x2,
                                 double y2,
                                 double px,
                                 double py)

Measures the square of the shortest distance from the reference point to a point on the line segment. If the point is on the segment, the result will be 0.

Parameters:

x1 - the first x coordinate of the segment

y1 - the first y coordinate of the segment

x2 - the second x coordinate of the segment

y2 - the second y coordinate of the segment

px - the x coordinate of the point

py - the y coordinate of the point

Returns:

the square of the distance from the point to the segment

ptSegDist

public static double ptSegDist(double x1,
                               double y1,
                               double x2,
                               double y2,
                               double px,
                               double py)

Measures the shortest distance from the reference point to a point on the line segment. If the point is on the segment, the result will be 0.

Parameters:

x1 - the first x coordinate of the segment

y1 - the first y coordinate of the segment

x2 - the second x coordinate of the segment

y2 - the second y coordinate of the segment

px - the x coordinate of the point

py - the y coordinate of the point

Returns:

the distance from the point to the segment

ptSegDistSq

public double ptSegDistSq(double px,
                          double py)

Measures the square of the shortest distance from the reference point to a point on this line segment. If the point is on the segment, the result will be 0.

Parameters:

px - the x coordinate of the point

py - the y coordinate of the point

Returns:

the square of the distance from the point to the segment

See Also:

ptSegDistSq(double, double, double, double, double, double)

ptSegDistSq

public double ptSegDistSq(Point2D p)

Measures the square of the shortest distance from the reference point to a point on this line segment. If the point is on the segment, the result will be 0.

Parameters:

p - the point

Returns:

the square of the distance from the point to the segment

Throws:

java.lang.NullPointerException - if p is null

See Also:

ptSegDistSq(double, double, double, double, double, double)

ptSegDist

public double ptSegDist(double px,
                        double py)

Measures the shortest distance from the reference point to a point on this line segment. If the point is on the segment, the result will be 0.

Parameters:

px - the x coordinate of the point

py - the y coordinate of the point

Returns:

the distance from the point to the segment

See Also:

ptSegDist(double, double, double, double, double, double)

ptSegDist

public double ptSegDist(Point2D p)

Measures the shortest distance from the reference point to a point on this line segment. If the point is on the segment, the result will be 0.

Parameters:

p - the point

Returns:

the distance from the point to the segment

Throws:

java.lang.NullPointerException - if p is null

See Also:

ptSegDist(double, double, double, double, double, double)