math.geom2d.conic
Class Circle2D

java.lang.Object
  math.geom2d.curve.AbstractContinuousCurve2D
      math.geom2d.curve.AbstractSmoothCurve2D
          math.geom2d.conic.Ellipse2D
              math.geom2d.conic.Circle2D

All Implemented Interfaces:

Serializable, Cloneable, CircleLine2D, CirculinearBoundary2D, CirculinearContinuousCurve2D, CirculinearContour2D, CirculinearCurve2D, CirculinearElement2D, CirculinearShape2D, ContinuousCirculinearCurve2D, CircularShape2D, Conic2D, ContinuousCurve2D, Curve2D, SmoothCurve2D, Boundary2D, ContinuousBoundary2D, ContinuousOrientedCurve2D, OrientedCurve2D, SmoothBoundary2D, SmoothOrientedCurve2D, Shape2D

public class Circle2D
extends Ellipse2D
implements Cloneable, CirculinearElement2D, CirculinearBoundary2D, CircularShape2D, CircleLine2D

A circle in the plane, defined as the set of points located at an equal distance from the circle center. A circle is a particular ellipse, with first and second axis length equal.

Author:

dlegland

See Also:

Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from interface math.geom2d.conic.Conic2D

Conic2D.Type

Field Summary

protected double

r the radius of the circle.

Fields inherited from class math.geom2d.conic.Ellipse2D

direct, r1, r2, theta, xc, yc

Fields inherited from interface math.geom2d.Shape2D

ACCURACY

Constructor Summary

Circle2D()
Empty constructor: center 0,0 and radius 0.

Circle2D(double xcenter, double ycenter, double radius)
Create a new circle with specified center and radius

Circle2D(double xcenter, double ycenter, double radius, boolean direct)
Create a new circle with specified center, radius and orientation.

Circle2D(Point2D center, double radius)
Create a new circle with specified point center and radius

Circle2D(Point2D center, double radius, boolean direct)
Create a new circle with specified center, radius and orientation

Method Summary

GeneralPath	appendPath(GeneralPath path) Add the path of the ellipse to the given path.
CurveSet2D<? extends CircularShape2D>	clip(Box2D box) Clip the circle by a box.
Circle2D	clone() Overrides Object declaration to ensure Curve2D implementation are cloned as Curve2D.
boolean	contains(double x, double y) Return true if the point (x, y) lies exactly on the circle.
static Circle2D	create(Point2D center, double radius) Creates a circle from a center and a radius.
static Circle2D	create(Point2D p1, Point2D p2, Point2D p3) Creates a circle containing 3 points.
void	draw(Graphics2D g2) Draws the curve on the given Graphics2D object.
boolean	equals(Object obj)
CirculinearDomain2D	getBuffer(double dist) Computes the buffer of the shape, formed by the set of points located at a distance from the shape that is lower or equal to d.
double[]	getConicCoefficients() Returns Cartesian equation of the circle: (x-xc)^2 + (y-yc)^2 = r^2, giving: x^2 + 0*x*y + y^2 -2*xc*x -2*yc*y + xc*xc+yc*yc-r*r = 0.
Conic2D.Type	getConicType()
Collection<? extends Circle2D>	getContinuousCurves() Returns the collection of continuous curves which constitute this curve.
double	getDistance(double x, double y) get the distance of the shape to the given point, specified by x and y, or the distance of point to the frontier of the shape in the case of a plain (i.e. fillable) shape.
double	getDistance(Point2D point) get the distance of the shape to the given point, or the distance of point to the frontier of the shape in the case of a plain shape.
double	getEccentricity() Return 0, which is the eccentricity of a circle by definition.
Point2D	getFirstPoint() Get the first point of the circle, which is the same as the last point.
Point2D	getFocus1() Return the first focus, which for a circle is the same point as the center.
Point2D	getFocus2() Return the second focus, which for a circle is the same point as the center.
static Collection<Point2D>	getIntersections(Circle2D circle1, Circle2D circle2)
static Collection<Point2D>	getIntersections(CircularShape2D circle, LinearShape2D line) Compute intersections of a circle with a line.
Collection<Point2D>	getIntersections(LinearShape2D line) Compute intersections of the circle with a line.
Point2D	getLastPoint() Get the last point of the circle, which is the same as the first point.
double	getLength() Returns perimeter of the circle (equal to 2*PI*radius).
double	getLength(double pos)
Circle2D	getParallel(double d) Returns the parallel circle located at a distance d from this circle.
Point2D	getPoint(double t) Get the position of the curve from internal parametric representation, depending on the parameter t.
double	getPosition(double length)
double	getPosition(Point2D point) Get position of the point on the curve.
double	getRadius()
Circle2D	getReverseCurve() Returns the circle with same center and same radius, but with the other orientation.
double	getSignedDistance(double x, double y) The same as getSignedDistance(Point2D), but by passing 2 double as arguments.
double	getSignedDistance(Point2D point) Get the signed distance of the curve to the given point: this distance is positive if the point lies outside the shape, and is negative if the point lies inside the shape.
Collection<? extends Circle2D>	getSmoothPieces() Returns a set of smooth curves, which contains only the circle.
CircleArc2D	getSubCurve(double t0, double t1) Returns a new CircleArc2D. t0 and t1 are position on circle.
Circle2D	getSupportingCircle() Returns the circle itself.
Vector2D	getTangent(double t)
boolean	isCircle()
boolean	isInside(Point2D point) Test whether the point is inside the circle.
void	setCircle(double xc, double yc, double r) Deprecated. conics will become immutable in a future release
void	setCircle(Point2D center, double r) Deprecated. conics will become immutable in a future release
void	setRadius(double radius) Deprecated. conics will become immutable in a future release
String	toString()
CircleLine2D	transform(CircleInversion2D inv) Transforms the shape by a circle inversion.

Methods inherited from class math.geom2d.conic.Ellipse2D

contains, create, create, create, create, create, fill, getAngle, getBoundaryCurves, getBoundingBox, getCenter, getCurvature, getDomain, getGeneralPath, getProjectedPoint, getProjectedVector, getRho, getSemiMajorAxisLength, getSemiMinorAxisLength, getT0, getT1, getVector1, getVector2, getWindingAngle, isBounded, isClosed, isDirect, isEmpty, project, reduceCentered, setCenter, setCenter, setEllipse, setEllipse, setEllipse, setEllipse, transform, transformCentered

Methods inherited from class math.geom2d.curve.AbstractSmoothCurve2D

getLeftTangent, getRightTangent, getSingularPoints, isSingular

Methods inherited from class math.geom2d.curve.AbstractContinuousCurve2D

getAsAWTShape, getAsPolyline, wrapCurve

Methods inherited from class java.lang.Object

finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Methods inherited from interface math.geom2d.curve.ContinuousCurve2D

getAsPolyline, getLeftTangent, getRightTangent, isClosed

Methods inherited from interface math.geom2d.curve.Curve2D

getAsAWTShape, getSingularPoints, getT0, getT1, isSingular, project

Methods inherited from interface math.geom2d.Shape2D

contains, getBoundingBox, isBounded, isEmpty

Methods inherited from interface math.geom2d.domain.SmoothBoundary2D

transform

Methods inherited from interface math.geom2d.curve.SmoothCurve2D

getCurvature

Methods inherited from interface math.geom2d.domain.Boundary2D

fill, getBoundaryCurves, getDomain

Field Detail

r

protected double r

the radius of the circle.

Constructor Detail

Circle2D

public Circle2D()

Empty constructor: center 0,0 and radius 0.

Circle2D

public Circle2D(Point2D center,
                double radius)

Create a new circle with specified point center and radius

Circle2D

public Circle2D(Point2D center,
                double radius,
                boolean direct)

Create a new circle with specified center, radius and orientation

Circle2D

public Circle2D(double xcenter,
                double ycenter,
                double radius)

Create a new circle with specified center and radius

Circle2D

public Circle2D(double xcenter,
                double ycenter,
                double radius,
                boolean direct)

Create a new circle with specified center, radius and orientation.

Method Detail

create

public static Circle2D create(Point2D center,
                              double radius)

Creates a circle from a center and a radius.

create

public static Circle2D create(Point2D p1,
                              Point2D p2,
                              Point2D p3)

Creates a circle containing 3 points.

getIntersections

public static Collection<Point2D> getIntersections(Circle2D circle1,
                                                   Circle2D circle2)

getIntersections

public static Collection<Point2D> getIntersections(CircularShape2D circle,
                                                   LinearShape2D line)

Compute intersections of a circle with a line. Return an array of Point2D, of size 0, 1 or 2 depending on the distance between circle and line. If there are 2 intersections points, the first one in the array is the first one on the line.

getRadius

public double getRadius()

setRadius

@Deprecated
public void setRadius(double radius)

Deprecated. conics will become immutable in a future release

setCircle

@Deprecated
public void setCircle(double xc,
                                 double yc,
                                 double r)

Deprecated. conics will become immutable in a future release

setCircle

@Deprecated
public void setCircle(Point2D center,
                                 double r)

Deprecated. conics will become immutable in a future release

getSupportingCircle

public Circle2D getSupportingCircle()

Returns the circle itself.

Specified by:

getSupportingCircle in interface CircularShape2D

getConicType

public Conic2D.Type getConicType()

Specified by:

getConicType in interface Conic2D

Overrides:

getConicType in class Ellipse2D

isCircle

public boolean isCircle()

Overrides:

isCircle in class Ellipse2D

getConicCoefficients

public double[] getConicCoefficients()

Returns Cartesian equation of the circle:

(x-xc)^2 + (y-yc)^2 = r^2, giving:

x^2 + 0*x*y + y^2 -2*xc*x -2*yc*y + xc*xc+yc*yc-r*r = 0.

Specified by:

getConicCoefficients in interface Conic2D

Overrides:

getConicCoefficients in class Ellipse2D

getEccentricity

public double getEccentricity()

Return 0, which is the eccentricity of a circle by definition.

Specified by:

getEccentricity in interface Conic2D

Overrides:

getEccentricity in class Ellipse2D

getFocus1

public Point2D getFocus1()

Return the first focus, which for a circle is the same point as the center.

Overrides:

getFocus1 in class Ellipse2D

getFocus2

public Point2D getFocus2()

Return the second focus, which for a circle is the same point as the center.

Overrides:

getFocus2 in class Ellipse2D

getBuffer

public CirculinearDomain2D getBuffer(double dist)

Description copied from interface: CirculinearShape2D

Computes the buffer of the shape, formed by the set of points located at a distance from the shape that is lower or equal to d.

Specified by:

getBuffer in interface CirculinearShape2D

Parameters:

dist - the maximal distance between a point of the buffer and the shape

Returns:

the buffer of the shape

getParallel

public Circle2D getParallel(double d)

Returns the parallel circle located at a distance d from this circle. For direct circle, distance is positive outside of the circle, and negative inside. This is the contrary for indirect circles.

Specified by:

getParallel in interface CircleLine2D

Specified by:

getParallel in interface CirculinearContinuousCurve2D

Specified by:

getParallel in interface CirculinearContour2D

Specified by:

getParallel in interface CirculinearCurve2D

Specified by:

getParallel in interface CirculinearElement2D

Specified by:

getParallel in interface ContinuousCirculinearCurve2D

Overrides:

getParallel in class Ellipse2D

Parameters:

d - the distance between the original curve and he parallel curve.

Returns:

the parallel curve

getLength

public double getLength()

Returns perimeter of the circle (equal to 2*PI*radius).

Specified by:

getLength in interface CirculinearCurve2D

Returns:

the length of the curve

getLength

public double getLength(double pos)

Specified by:

getLength in interface CirculinearCurve2D

Returns:

the length from the beginning to the position given by pos

getPosition

public double getPosition(double length)

Specified by:

getPosition in interface CirculinearCurve2D

Returns:

the position located at distance 'length' from the origin

transform

public CircleLine2D transform(CircleInversion2D inv)

Description copied from interface: CirculinearShape2D

Transforms the shape by a circle inversion. The result is still an instance a CirculinearShape2D.

Specified by:

transform in interface CircleLine2D

Specified by:

transform in interface CirculinearBoundary2D

Specified by:

transform in interface CirculinearContinuousCurve2D

Specified by:

transform in interface CirculinearContour2D

Specified by:

transform in interface CirculinearCurve2D

Specified by:

transform in interface CirculinearElement2D

Specified by:

transform in interface CirculinearShape2D

Specified by:

transform in interface ContinuousCirculinearCurve2D

Parameters:

inv - the circle inversion

Returns:

the transformed shape

getTangent

public Vector2D getTangent(double t)

Specified by:

getTangent in interface SmoothCurve2D

Overrides:

getTangent in class Ellipse2D

getSmoothPieces

public Collection<? extends Circle2D> getSmoothPieces()

Returns a set of smooth curves, which contains only the circle.

Specified by:

getSmoothPieces in interface CirculinearContinuousCurve2D

Specified by:

getSmoothPieces in interface ContinuousCirculinearCurve2D

Specified by:

getSmoothPieces in interface ContinuousCurve2D

Overrides:

getSmoothPieces in class AbstractSmoothCurve2D

isInside

public boolean isInside(Point2D point)

Test whether the point is inside the circle. The test is performed by translating the point, and re-scaling it such that its coordinates are expressed in unit circle basis.

Specified by:

isInside in interface Boundary2D

Specified by:

isInside in interface OrientedCurve2D

Overrides:

isInside in class Ellipse2D

Parameters:

point - a point in the plane

Returns:

true if the point is on the left side of the curve.

getSignedDistance

public double getSignedDistance(Point2D point)

Description copied from interface: OrientedCurve2D

Get the signed distance of the curve to the given point: this distance is positive if the point lies outside the shape, and is negative if the point lies inside the shape. In this case, absolute value of distance is equals to the distance to the border of the shape.

Specified by:

getSignedDistance in interface OrientedCurve2D

Overrides:

getSignedDistance in class Ellipse2D

Parameters:

point - a point of the plane

Returns:

the signed distance to the curve

getSignedDistance

public double getSignedDistance(double x,
                                double y)

Description copied from interface: OrientedCurve2D

The same as getSignedDistance(Point2D), but by passing 2 double as arguments.

Specified by:

getSignedDistance in interface OrientedCurve2D

Overrides:

getSignedDistance in class Ellipse2D

Parameters:

x - x-coord of a point

y - y-coord of a point

Returns:

the signed distance of the point (x,y) to the curve

getPoint

public Point2D getPoint(double t)

Get the position of the curve from internal parametric representation, depending on the parameter t. This parameter is between the two limits 0 and 2*Math.PI.

Specified by:

getPoint in interface Curve2D

Overrides:

getPoint in class Ellipse2D

getFirstPoint

public Point2D getFirstPoint()

Get the first point of the circle, which is the same as the last point.

Specified by:

getFirstPoint in interface Curve2D

Overrides:

getFirstPoint in class Ellipse2D

Returns:

the first point of the curve

getLastPoint

public Point2D getLastPoint()

Get the last point of the circle, which is the same as the first point.

Specified by:

getLastPoint in interface Curve2D

Overrides:

getLastPoint in class Ellipse2D

Returns:

the last point of the curve.

getPosition

public double getPosition(Point2D point)

Description copied from interface: Curve2D

Get position of the point on the curve. If the point does not belong to the curve, return Double.NaN.

Specified by:

getPosition in interface Curve2D

Overrides:

getPosition in class Ellipse2D

Parameters:

point - a point belonging to the curve

Returns:

the position of the point on the curve

getReverseCurve

public Circle2D getReverseCurve()

Returns the circle with same center and same radius, but with the other orientation.

Specified by:

getReverseCurve in interface CircleLine2D

Specified by:

getReverseCurve in interface CirculinearBoundary2D

Specified by:

getReverseCurve in interface CirculinearContinuousCurve2D

Specified by:

getReverseCurve in interface CirculinearContour2D

Specified by:

getReverseCurve in interface CirculinearCurve2D

Specified by:

getReverseCurve in interface CirculinearElement2D

Specified by:

getReverseCurve in interface ContinuousCirculinearCurve2D

Specified by:

getReverseCurve in interface CircularShape2D

Specified by:

getReverseCurve in interface Conic2D

Specified by:

getReverseCurve in interface ContinuousCurve2D

Specified by:

getReverseCurve in interface Curve2D

Specified by:

getReverseCurve in interface SmoothCurve2D

Specified by:

getReverseCurve in interface Boundary2D

Specified by:

getReverseCurve in interface ContinuousBoundary2D

Specified by:

getReverseCurve in interface ContinuousOrientedCurve2D

Specified by:

getReverseCurve in interface OrientedCurve2D

Specified by:

getReverseCurve in interface SmoothBoundary2D

Specified by:

getReverseCurve in interface SmoothOrientedCurve2D

Overrides:

getReverseCurve in class Ellipse2D

getSubCurve

public CircleArc2D getSubCurve(double t0,
                               double t1)

Returns a new CircleArc2D. t0 and t1 are position on circle.

Specified by:

getSubCurve in interface CirculinearContinuousCurve2D

Specified by:

getSubCurve in interface CirculinearCurve2D

Specified by:

getSubCurve in interface CirculinearElement2D

Specified by:

getSubCurve in interface ContinuousCirculinearCurve2D

Specified by:

getSubCurve in interface CircularShape2D

Specified by:

getSubCurve in interface ContinuousCurve2D

Specified by:

getSubCurve in interface Curve2D

Specified by:

getSubCurve in interface SmoothCurve2D

Specified by:

getSubCurve in interface ContinuousOrientedCurve2D

Specified by:

getSubCurve in interface SmoothOrientedCurve2D

Overrides:

getSubCurve in class Ellipse2D

Parameters:

t0 - position of the start of the sub-curve

t1 - position of the end of the sub-curve

Returns:

the portion of original curve comprised between t0 and t1.

getContinuousCurves

public Collection<? extends Circle2D> getContinuousCurves()

Description copied from interface: Curve2D

Returns the collection of continuous curves which constitute this curve.

Specified by:

getContinuousCurves in interface CirculinearBoundary2D

Specified by:

getContinuousCurves in interface CirculinearCurve2D

Specified by:

getContinuousCurves in interface Curve2D

Overrides:

getContinuousCurves in class Ellipse2D

Returns:

a collection of continuous curves.

getDistance

public double getDistance(Point2D point)

Description copied from interface: Shape2D

get the distance of the shape to the given point, or the distance of point to the frontier of the shape in the case of a plain shape.

Specified by:

getDistance in interface Shape2D

Overrides:

getDistance in class Ellipse2D

getDistance

public double getDistance(double x,
                          double y)

Description copied from interface: Shape2D

get the distance of the shape to the given point, specified by x and y, or the distance of point to the frontier of the shape in the case of a plain (i.e. fillable) shape.

Specified by:

getDistance in interface Shape2D

Overrides:

getDistance in class Ellipse2D

getIntersections

public Collection<Point2D> getIntersections(LinearShape2D line)

Compute intersections of the circle with a line. Return an array of Point2D, of size 0, 1 or 2 depending on the distance between circle and line. If there are 2 intersections points, the first one in the array is the first one on the line.

Specified by:

getIntersections in interface Curve2D

Overrides:

getIntersections in class Ellipse2D

clip

public CurveSet2D<? extends CircularShape2D> clip(Box2D box)

Clip the circle by a box. The result is an instance of CurveSet2D, which contains only instances of CircleArc2D or Circle2D. If the circle is not clipped, the result is an instance of CurveSet2D which contains 0 curves.

Specified by:

clip in interface CirculinearBoundary2D

Specified by:

clip in interface CirculinearContinuousCurve2D

Specified by:

clip in interface CirculinearCurve2D

Specified by:

clip in interface CirculinearElement2D

Specified by:

clip in interface ContinuousCirculinearCurve2D

Specified by:

clip in interface CircularShape2D

Specified by:

clip in interface Conic2D

Specified by:

clip in interface ContinuousCurve2D

Specified by:

clip in interface Curve2D

Specified by:

clip in interface SmoothCurve2D

Specified by:

clip in interface ContinuousOrientedCurve2D

Specified by:

clip in interface OrientedCurve2D

Specified by:

clip in interface SmoothOrientedCurve2D

Specified by:

clip in interface Shape2D

Overrides:

clip in class Ellipse2D

Parameters:

box - the clipping box

Returns:

the clipped shape

contains

public boolean contains(double x,
                        double y)

Return true if the point (x, y) lies exactly on the circle.

Specified by:

contains in interface Shape2D

Overrides:

contains in class Ellipse2D

appendPath

public GeneralPath appendPath(GeneralPath path)

Description copied from class: Ellipse2D

Add the path of the ellipse to the given path.

Specified by:

appendPath in interface ContinuousCurve2D

Overrides:

appendPath in class Ellipse2D

Parameters:

path - the path to be completed

Returns:

the completed path

draw

public void draw(Graphics2D g2)

Description copied from interface: Curve2D

Draws the curve on the given Graphics2D object.

Specified by:

draw in interface Curve2D

Specified by:

draw in interface Shape2D

Overrides:

draw in class Ellipse2D

Parameters:

g2 - the graphics to draw the curve

toString

public String toString()

Overrides:

toString in class Ellipse2D

equals

public boolean equals(Object obj)

Overrides:

equals in class Ellipse2D

clone

public Circle2D clone()

Description copied from interface: Curve2D

Overrides Object declaration to ensure Curve2D implementation are cloned as Curve2D.

Specified by:

clone in interface Curve2D

Overrides:

clone in class Ellipse2D

Returns:

the cloned curve