```
public class Circle
extends Object
```
This class provides operations for handling the usage of Circles and arcs in Geometries.
Date: Oct 15, 2007

Author:

Tom Acree

Nested Class Summary

Nested Classes
Modifier and Type Class Description

class Circle.Arc

Constructor Summary

Constructors
Modifier	Constructor	Description
`protected`	`Circle()`	Creates a circle whose center is at the origin and whose radius is 0.
	`Circle(double xCenter, double yCenter, double radius)`	Create a circle using the x/y coordinates for the center.
	`Circle(double xLeft, double yUpper, double xRight, double yLower)`	Creates a circle based on bounding box.
	`Circle(double x1, double y1, double x2, double y2, double x3, double y3)`	Three point method of circle construction.
	`Circle(Coordinate center, double radius)`	Create a circle with a defined center and radius
	`Circle(Coordinate point1, Coordinate point2, Coordinate point3)`	Three point method of circle construction.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`Circle.Arc`	`createArc(Coordinate p1, Coordinate p2, Coordinate p3)`
`double`	`distanceFromCenter(Coordinate p)`
`boolean`	`equals(Object o)`
`double`	`getAngle(Coordinate p)`	Returns the angle of the point from the center and the horizontal line from the center.
`Coordinate`	`getCenter()`
`Coordinate`	`getPoint(double angle)`
`double`	`getRadius()`
`int`	`hashCode()`
`static Coordinate[]`	`linearizeArc(double x1, double y1, double x2, double y2, double x3, double y3)`	Given 2 points defining an arc on the circle, interpolates the circle into a collection of points that provide connected chords that approximate the arc based on the tolerance value.
`static Coordinate[]`	`linearizeArc(double x1, double y1, double x2, double y2, double x3, double y3, double tolerence)`	Given 2 points defining an arc on the circle, interpolates the circle into a collection of points that provide connected chords that approximate the arc based on the tolerance value.
`Coordinate[]`	`linearizeArc(Coordinate p1, Coordinate p2, Coordinate p3, double tolerence)`	Given 2 points defining an arc on the circle, interpolates the circle into a collection of points that provide connected chords that approximate the arc based on the tolerance value.
`static Coordinate[]`	`linearizeCircle(double x1, double y1, double x2, double y2, double x3, double y3)`	Given a circle defined by the 3 points, creates a linearized interpolation of the circle starting and ending on the first coordinate.
`static Coordinate[]`	`linearizeCircle(Coordinate p1, Coordinate p2, Coordinate p3, double tolerance)`	Given a circle defined by the 3 points, creates a linearized interpolation of the circle starting and ending on the first coordinate.
`void`	`move(double x, double y)`	Move the circle to a new center
`static double`	`normalizeAngle(double angle)`	Returns an angle between 0 and 2*PI.
`void`	`shift(double deltaX, double deltaY)`	shift the center of the circle by delta X and delta Y
`static double`	`subtractAngles(double a1, double a2)`	Returns the angle between the angles a1 and a2 in radians.
`String`	`toString()`

Methods inherited from class Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait

- Constructor Detail
  - Circle
```
protected Circle()
```
    Creates a circle whose center is at the origin and whose radius is 0.
  - Circle
```
public Circle(Coordinate center,
              double radius)
```
    Create a circle with a defined center and radius
    
    Parameters:
    
    center - The coordinate representing the center of the circle
    
    radius - The radius of the circle
  - Circle
```
public Circle(double xCenter,
              double yCenter,
              double radius)
```
    Create a circle using the x/y coordinates for the center.
    
    Parameters:
    
    xCenter - The x coordinate of the circle's center
    
    yCenter - The y coordinate of the circle's center
    
    radius - the radius of the circle
  - Circle
```
public Circle(double xLeft,
              double yUpper,
              double xRight,
              double yLower)
```
    Creates a circle based on bounding box. It is possible for the user of this class to pass bounds to this method that do not represent a square. If this is the case, we must force the bounding rectangle to be a square. To this end, we check the box and set the side of the box to the larger dimension of the rectangle
  - Circle
```
public Circle(Coordinate point1,
              Coordinate point2,
              Coordinate point3)
```
    Three point method of circle construction. All three points must be on the circumference of the circle.
  - Circle
```
public Circle(double x1,
              double y1,
              double x2,
              double y2,
              double x3,
              double y3)
```
    Three point method of circle construction. All three points must be on the circumference of the circle.
- Method Detail
  - shift
```
public void shift(double deltaX,
                  double deltaY)
```
    shift the center of the circle by delta X and delta Y
  - move
```
public void move(double x,
                 double y)
```
    Move the circle to a new center
  - getCenter
```
public Coordinate getCenter()
```
  - getRadius
```
public double getRadius()
```
  - linearizeArc
```
public static Coordinate[] linearizeArc(double x1,
                                        double y1,
                                        double x2,
                                        double y2,
                                        double x3,
                                        double y3,
                                        double tolerence)
```
    Given 2 points defining an arc on the circle, interpolates the circle into a collection of points that provide connected chords that approximate the arc based on the tolerance value. The tolerance value specifies the maximum distance between a chord and the circle.
    
    Parameters:
    
    x1 - x coordinate of point 1
    
    y1 - y coordinate of point 1
    
    x2 - x coordinate of point 2
    
    y2 - y coordinate of point 2
    
    x3 - x coordinate of point 3
    
    y3 - y coordinate of point 3
    
    tolerence - maximum distance between the center of the chord and the outer edge of the circle
    
    Returns:
    
    an ordered list of Coordinates representing a series of chords approximating the arc.
  - linearizeArc
```
public static Coordinate[] linearizeArc(double x1,
                                        double y1,
                                        double x2,
                                        double y2,
                                        double x3,
                                        double y3)
```
    Given 2 points defining an arc on the circle, interpolates the circle into a collection of points that provide connected chords that approximate the arc based on the tolerance value. This method uses a tolerence value of 1/100 of the length of the radius.
    
    Parameters:
    
    x1 - x coordinate of point 1
    
    y1 - y coordinate of point 1
    
    x2 - x coordinate of point 2
    
    y2 - y coordinate of point 2
    
    x3 - x coordinate of point 3
    
    y3 - y coordinate of point 3
    
    Returns:
    
    an ordered list of Coordinates representing a series of chords approximating the arc.
  - linearizeCircle
```
public static Coordinate[] linearizeCircle(double x1,
                                           double y1,
                                           double x2,
                                           double y2,
                                           double x3,
                                           double y3)
```
    Given a circle defined by the 3 points, creates a linearized interpolation of the circle starting and ending on the first coordinate. This method uses a tolerence value of 1/100 of the length of the radius.
    
    Parameters:
    
    x1 - x coordinate of point 1
    
    y1 - y coordinate of point 1
    
    x2 - x coordinate of point 2
    
    y2 - y coordinate of point 2
    
    x3 - x coordinate of point 3
    
    y3 - y coordinate of point 3
    
    Returns:
    
    an ordered list of Coordinates representing a series of chords approximating the arc.
  - linearizeCircle
```
public static Coordinate[] linearizeCircle(Coordinate p1,
                                           Coordinate p2,
                                           Coordinate p3,
                                           double tolerance)
```
    Given a circle defined by the 3 points, creates a linearized interpolation of the circle starting and ending on the first coordinate.
    
    Parameters:
    
    p1 - coordinate on the circle
    
    p2 - another coordinate on the circle
    
    p3 - yet another coordinate on the circle
    
    tolerance - maximum distance between the center of the chord and the outer edge of the circle
    
    Returns:
    
    an ordered list of Coordinates representing a series of chords approximating the circle.
  - linearizeArc
```
public Coordinate[] linearizeArc(Coordinate p1,
                                 Coordinate p2,
                                 Coordinate p3,
                                 double tolerence)
```
    Given 2 points defining an arc on the circle, interpolates the circle into a collection of points that provide connected chords that approximate the arc based on the tolerance value. The tolerance value specifies the maximum distance between a chord and the circle.
    
    Parameters:
    
    p1 - begin coordinate of the arc
    
    p2 - any other point on the arc
    
    p3 - end coordinate of the arc
    
    tolerence - maximum distance between the center of the chord and the outer edge of the circle
    
    Returns:
    
    an ordered list of Coordinates representing a series of chords approximating the arc.
  - equals
```
public boolean equals(Object o)
```
    Overrides:
    
    equals in class Object
  - hashCode
```
public int hashCode()
```
    Overrides:
    
    hashCode in class Object
  - toString
```
public String toString()
```
    Overrides:
    
    toString in class Object
  - getAngle
```
public double getAngle(Coordinate p)
```
    Returns the angle of the point from the center and the horizontal line from the center.
    
    Parameters:
    
    p - a point in space
    
    Returns:
    
    The angle of the point from the center of the circle
  - getPoint
```
public Coordinate getPoint(double angle)
```
  - distanceFromCenter
```
public double distanceFromCenter(Coordinate p)
```
    Parameters:
    
    p - A point in space
    
    Returns:
    
    The distance the point is from the center of the circle
  - createArc
```
public Circle.Arc createArc(Coordinate p1,
                            Coordinate p2,
                            Coordinate p3)
```
  - normalizeAngle
```
public static double normalizeAngle(double angle)
```
    Returns an angle between 0 and 2*PI. For example, 4*PI would get returned as 2*PI since they are equivalent.
    
    Parameters:
    
    angle - an angle in radians to normalize
    
    Returns:
    
    an angle between 0 and 2*PI
  - subtractAngles
```
public static double subtractAngles(double a1,
                                    double a2)
```
    Returns the angle between the angles a1 and a2 in radians. Angle is calculated in the counterclockwise direction.
    
    Parameters:
    
    a1 - first angle
    
    a2 - second angle
    
    Returns:
    
    the angle between a1 and a2 in the clockwise direction

Class Circle

Nested Class Summary

Constructor Summary

Method Summary

Methods inherited from class Object

Constructor Detail

Circle

Circle

Circle

Circle

Circle

Circle

Method Detail

shift

move

getCenter

getRadius

linearizeArc

linearizeArc

linearizeCircle

linearizeCircle

linearizeArc

equals

hashCode

toString

getAngle

getPoint

distanceFromCenter

createArc

normalizeAngle

subtractAngles