math.geom2d.conic
Class Circle2D

java.lang.Object
  math.geom2d.conic.Ellipse2D
      math.geom2d.conic.Circle2D

All Implemented Interfaces:

java.awt.Shape, Conic2D, Boundary2D, ContinuousBoundary2D, ContinuousCurve2D, ContinuousOrientedCurve2D, Curve2D, OrientedCurve2D, SmoothCurve2D, SmoothOrientedCurve2D, Shape2D

public class Circle2D
extends Ellipse2D

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

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.conic.Conic2D

CIRCLE, ELLIPSE, HYPERBOLA, NOT_A_CONIC, PARABOLA, POINT, STRAIGHT_LINE, TWO_LINES

Fields inherited from interface math.geom2d.curve.ContinuousCurve2D

CLOSED_EDGE, LOOP, OPEN_EDGE

Fields inherited from interface math.geom2d.Shape2D

ACCURACY, defaultClipWindow, EMPTY_SET

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 and radius

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

Method Summary

java.awt.geom.GeneralPath	appendPath(java.awt.geom.GeneralPath path) Add the path of the ellipse to the given path.
CurveSet2D<? extends SmoothOrientedCurve2D>	clip(Box2D box) Clip the circle by a box.
boolean	contains(double x, double y) Return true if the point (x, y) lies exactly on the circle.
boolean	equals(java.lang.Object obj)
java.awt.Rectangle	getBounds() Return bounding box of the circle.
java.awt.geom.Rectangle2D	getBounds2D() Return more precise bounds of the circle.
double[]	getCartesianEquation() return 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.
int	getConicType()
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(java.awt.geom.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, whihc 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.
protected java.awt.geom.GeneralPath	getGeneralPath()
java.util.Collection<Point2D>	getIntersections(StraightObject2D 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	getLength1() Returns the length of the first semi-axis of the ellipse.
double	getLength2() Returns the length of the second semi-axis of the ellipse.
java.awt.geom.PathIterator	getPathIterator(java.awt.geom.AffineTransform trans) Return pathiterator for this circle.
java.awt.geom.PathIterator	getPathIterator(java.awt.geom.AffineTransform trans, double flatness) Return pathiterator for this circle.
Point2D	getPoint(double t) Get the position of the curve from internal parametric representation, depending on the parameter t.
Point2D	getPoint(double t, Point2D point) Get the position of the curve from internal parametric representation, depending on the parameter t.
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(java.awt.geom.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.
CircleArc2D	getSubCurve(double t0, double t1) return a new CircleArc2D. t0 and t1 are position on circle.
Vector2D	getTangent(double t)
boolean	isCircle()
boolean	isDegenerated()
boolean	isEllipse()
boolean	isHyperbola()
boolean	isParabola()
boolean	isPoint()
boolean	isStraightLine()
boolean	isTwoLines()
void	setCircle(double xc, double yc, double r)
void	setCircle(Point2D center, double r)
void	setRadius(double radius)

Methods inherited from class math.geom2d.conic.Ellipse2D

contains, contains, contains, getAngle, getAsPolyline, getBoundaryCurves, getBoundingBox, getCenter, getContinuousCurves, getCurvature, getProjectedPoint, getProjectedVector, getRho, getSmoothPieces, getT0, getT1, getVector1, getVector2, getWindingAngle, intersects, intersects, isBounded, isClosed, isDirect, isInside, project, setCenter, setCenter, setEllipse, setEllipse, setEllipse, setEllipse, toString, transform

Methods inherited from class java.lang.Object

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

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(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 and radius

Method Detail

getLength

public double getLength()

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

getRadius

public double getRadius()

setRadius

public void setRadius(double radius)

setCircle

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

setCircle

public void setCircle(Point2D center,
                      double r)

getConicType

public int getConicType()

Specified by:

getConicType in interface Conic2D

Overrides:

getConicType in class Ellipse2D

isEllipse

public boolean isEllipse()

Overrides:

isEllipse in class Ellipse2D

isParabola

public boolean isParabola()

Overrides:

isParabola in class Ellipse2D

isHyperbola

public boolean isHyperbola()

Overrides:

isHyperbola in class Ellipse2D

isCircle

public boolean isCircle()

Overrides:

isCircle in class Ellipse2D

isStraightLine

public boolean isStraightLine()

Overrides:

isStraightLine in class Ellipse2D

isTwoLines

public boolean isTwoLines()

Overrides:

isTwoLines in class Ellipse2D

isPoint

public boolean isPoint()

Overrides:

isPoint in class Ellipse2D

isDegenerated

public boolean isDegenerated()

Overrides:

isDegenerated in class Ellipse2D

getCartesianEquation

public double[] getCartesianEquation()

return 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:

getCartesianEquation in interface Conic2D

Overrides:

getCartesianEquation in class Ellipse2D

getLength1

public double getLength1()

Returns the length of the first semi-axis of the ellipse.

Overrides:

getLength1 in class Ellipse2D

getLength2

public double getLength2()

Returns the length of the second semi-axis of the ellipse.

Overrides:

getLength2 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, whihc 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

getTangent

public Vector2D getTangent(double t)

Specified by:

getTangent in interface SmoothCurve2D

Overrides:

getTangent in class Ellipse2D

getSignedDistance

public double getSignedDistance(java.awt.geom.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

getPoint

public Point2D getPoint(double t,
                        Point2D point)

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 Conic2D

Specified by:

getReverseCurve in interface Boundary2D

Specified by:

getReverseCurve in interface ContinuousBoundary2D

Specified by:

getReverseCurve in interface ContinuousCurve2D

Specified by:

getReverseCurve in interface ContinuousOrientedCurve2D

Specified by:

getReverseCurve in interface Curve2D

Specified by:

getReverseCurve in interface OrientedCurve2D

Specified by:

getReverseCurve in interface SmoothCurve2D

Specified by:

getReverseCurve in interface SmoothOrientedCurve2D

Overrides:

getReverseCurve in class Ellipse2D

getSubCurve

public CircleArc2D getSubCurve(double t0,
                               double t1)

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

Specified by:

getSubCurve in interface ContinuousCurve2D

Specified by:

getSubCurve in interface ContinuousOrientedCurve2D

Specified by:

getSubCurve in interface Curve2D

Specified by:

getSubCurve in interface SmoothCurve2D

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.

getDistance

public double getDistance(java.awt.geom.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 java.util.Collection<Point2D> getIntersections(StraightObject2D line)

Compute intersections of the circle with a line. Return an array of Point2D, of size 0, 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 SmoothOrientedCurve2D> 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 Conic2D

Specified by:

clip in interface ContinuousCurve2D

Specified by:

clip in interface ContinuousOrientedCurve2D

Specified by:

clip in interface Curve2D

Specified by:

clip in interface OrientedCurve2D

Specified by:

clip in interface SmoothCurve2D

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 java.awt.Shape

Overrides:

contains in class Ellipse2D

getBounds

public java.awt.Rectangle getBounds()

Return bounding box of the circle.

Specified by:

getBounds in interface java.awt.Shape

Overrides:

getBounds in class Ellipse2D

getBounds2D

public java.awt.geom.Rectangle2D getBounds2D()

Return more precise bounds of the circle.

Specified by:

getBounds2D in interface java.awt.Shape

Overrides:

getBounds2D in class Ellipse2D

appendPath

public java.awt.geom.GeneralPath appendPath(java.awt.geom.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

getGeneralPath

protected java.awt.geom.GeneralPath getGeneralPath()

Overrides:

getGeneralPath in class Ellipse2D

getPathIterator

public java.awt.geom.PathIterator getPathIterator(java.awt.geom.AffineTransform trans)

Return pathiterator for this circle.

Specified by:

getPathIterator in interface java.awt.Shape

Overrides:

getPathIterator in class Ellipse2D

getPathIterator

public java.awt.geom.PathIterator getPathIterator(java.awt.geom.AffineTransform trans,
                                                  double flatness)

Return pathiterator for this circle.

Specified by:

getPathIterator in interface java.awt.Shape

Overrides:

getPathIterator in class Ellipse2D

equals

public boolean equals(java.lang.Object obj)

Overrides:

equals in class Ellipse2D