Java™ Platform
Standard Ed. 6

java.awt.geom
Class Arc2D

java.lang.Object
  extended by java.awt.geom.RectangularShape
      extended by java.awt.geom.Arc2D
All Implemented Interfaces:
Shape, Cloneable
Direct Known Subclasses:
Arc2D.Double, Arc2D.Float

public abstract class Arc2D
extends RectangularShape

Arc2D is the abstract superclass for all objects that store a 2D arc defined by a framing rectangle, start angle, angular extent (length of the arc), and a closure type (OPEN, CHORD, or PIE).

The arc is a partial section of a full ellipse which inscribes the framing rectangle of its parent RectangularShape. The angles are specified relative to the non-square framing rectangle such that 45 degrees always falls on the line from the center of the ellipse to the upper right corner of the framing rectangle. As a result, if the framing rectangle is noticeably longer along one axis than the other, the angles to the start and end of the arc segment will be skewed farther along the longer axis of the frame.

The actual storage representation of the coordinates is left to the subclass.

Since:
1.2

Nested Class Summary
static class Arc2D.Double
          This class defines an arc specified in double precision.
static class Arc2D.Float
          This class defines an arc specified in float precision.
 
Field Summary
static int CHORD
          The closure type for an arc closed by drawing a straight line segment from the start of the arc segment to the end of the arc segment.
static int OPEN
          The closure type for an open arc with no path segments connecting the two ends of the arc segment.
static int PIE
          The closure type for an arc closed by drawing straight line segments from the start of the arc segment to the center of the full ellipse and from that point to the end of the arc segment.
 
Constructor Summary
protected Arc2D(int type)
          This is an abstract class that cannot be instantiated directly.
 
Method Summary
 boolean contains(double x, double y)
          Determines whether or not the specified point is inside the boundary of the arc.
 boolean contains(double x, double y, double w, double h)
          Determines whether or not the interior of the arc entirely contains the specified rectangle.
 boolean contains(Rectangle2D r)
          Determines whether or not the interior of the arc entirely contains the specified rectangle.
 boolean containsAngle(double angle)
          Determines whether or not the specified angle is within the angular extents of the arc.
 boolean equals(Object obj)
          Determines whether or not the specified Object is equal to this Arc2D.
abstract  double getAngleExtent()
          Returns the angular extent of the arc.
abstract  double getAngleStart()
          Returns the starting angle of the arc.
 int getArcType()
          Returns the arc closure type of the arc: OPEN, CHORD, or PIE.
 Rectangle2D getBounds2D()
          Returns the high-precision framing rectangle of the arc.
 Point2D getEndPoint()
          Returns the ending point of the arc.
 PathIterator getPathIterator(AffineTransform at)
          Returns an iteration object that defines the boundary of the arc.
 Point2D getStartPoint()
          Returns the starting point of the arc.
 int hashCode()
          Returns the hashcode for this Arc2D.
 boolean intersects(double x, double y, double w, double h)
          Determines whether or not the interior of the arc intersects the interior of the specified rectangle.
protected abstract  Rectangle2D makeBounds(double x, double y, double w, double h)
          Constructs a Rectangle2D of the appropriate precision to hold the parameters calculated to be the framing rectangle of this arc.
abstract  void setAngleExtent(double angExt)
          Sets the angular extent of this arc to the specified double value.
 void setAngles(double x1, double y1, double x2, double y2)
          Sets the starting angle and angular extent of this arc using two sets of coordinates.
 void setAngles(Point2D p1, Point2D p2)
          Sets the starting angle and angular extent of this arc using two points.
abstract  void setAngleStart(double angSt)
          Sets the starting angle of this arc to the specified double value.
 void setAngleStart(Point2D p)
          Sets the starting angle of this arc to the angle that the specified point defines relative to the center of this arc.
 void setArc(Arc2D a)
          Sets this arc to be the same as the specified arc.
abstract  void setArc(double x, double y, double w, double h, double angSt, double angExt, int closure)
          Sets the location, size, angular extents, and closure type of this arc to the specified double values.
 void setArc(Point2D loc, Dimension2D size, double angSt, double angExt, int closure)
          Sets the location, size, angular extents, and closure type of this arc to the specified values.
 void setArc(Rectangle2D rect, double angSt, double angExt, int closure)
          Sets the location, size, angular extents, and closure type of this arc to the specified values.
 void setArcByCenter(double x, double y, double radius, double angSt, double angExt, int closure)
          Sets the position, bounds, angular extents, and closure type of this arc to the specified values.
 void setArcByTangent(Point2D p1, Point2D p2, Point2D p3, double radius)
          Sets the position, bounds, and angular extents of this arc to the specified value.
 void setArcType(int type)
          Sets the closure type of this arc to the specified value: OPEN, CHORD, or PIE.
 void setFrame(double x, double y, double w, double h)
          Sets the location and size of the framing rectangle of this Shape to the specified rectangular values.
 
Methods inherited from class java.awt.geom.RectangularShape
clone, contains, getBounds, getCenterX, getCenterY, getFrame, getHeight, getMaxX, getMaxY, getMinX, getMinY, getPathIterator, getWidth, getX, getY, intersects, isEmpty, setFrame, setFrame, setFrameFromCenter, setFrameFromCenter, setFrameFromDiagonal, setFrameFromDiagonal
 
Methods inherited from class java.lang.Object
finalize, getClass, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

OPEN

public static final int OPEN
The closure type for an open arc with no path segments connecting the two ends of the arc segment.

Since:
1.2
See Also:
Constant Field Values

CHORD

public static final int CHORD
The closure type for an arc closed by drawing a straight line segment from the start of the arc segment to the end of the arc segment.

Since:
1.2
See Also:
Constant Field Values

PIE

public static final int PIE
The closure type for an arc closed by drawing straight line segments from the start of the arc segment to the center of the full ellipse and from that point to the end of the arc segment.

Since:
1.2
See Also:
Constant Field Values
Constructor Detail

Arc2D

protected Arc2D(int type)
This is an abstract class that cannot be instantiated directly. Type-specific implementation subclasses are available for instantiation and provide a number of formats for storing the information necessary to satisfy the various accessor methods below.

Parameters:
type - The closure type of this arc: OPEN, CHORD, or PIE.
Since:
1.2
See Also:
Arc2D.Float, Arc2D.Double
Method Detail

getAngleStart

public abstract double getAngleStart()
Returns the starting angle of the arc.

Returns:
A double value that represents the starting angle of the arc in degrees.
Since:
1.2
See Also:
setAngleStart(double)

getAngleExtent

public abstract double getAngleExtent()
Returns the angular extent of the arc.

Returns:
A double value that represents the angular extent of the arc in degrees.
Since:
1.2
See Also:
setAngleExtent(double)

getArcType

public int getArcType()
Returns the arc closure type of the arc: OPEN, CHORD, or PIE.

Returns:
One of the integer constant closure types defined in this class.
Since:
1.2
See Also:
setArcType(int)

getStartPoint

public Point2D getStartPoint()
Returns the starting point of the arc. This point is the intersection of the ray from the center defined by the starting angle and the elliptical boundary of the arc.

Returns:
A Point2D object representing the x,y coordinates of the starting point of the arc.
Since:
1.2

getEndPoint

public Point2D getEndPoint()
Returns the ending point of the arc. This point is the intersection of the ray from the center defined by the starting angle plus the angular extent of the arc and the elliptical boundary of the arc.

Returns:
A Point2D object representing the x,y coordinates of the ending point of the arc.
Since:
1.2

setArc

public abstract void setArc(double x,
                            double y,
                            double w,
                            double h,
                            double angSt,
                            double angExt,
                            int closure)
Sets the location, size, angular extents, and closure type of this arc to the specified double values.

Parameters:
x - The X coordinate of the upper-left corner of the arc.
y - The Y coordinate of the upper-left corner of the arc.
w - The overall width of the full ellipse of which this arc is a partial section.
h - The overall height of the full ellipse of which this arc is a partial section.
angSt - The starting angle of the arc in degrees.
angExt - The angular extent of the arc in degrees.
closure - The closure type for the arc: OPEN, CHORD, or PIE.
Since:
1.2

setArc

public void setArc(Point2D loc,
                   Dimension2D size,
                   double angSt,
                   double angExt,
                   int closure)
Sets the location, size, angular extents, and closure type of this arc to the specified values.

Parameters:
loc - The Point2D representing the coordinates of the upper-left corner of the arc.
size - The Dimension2D representing the width and height of the full ellipse of which this arc is a partial section.
angSt - The starting angle of the arc in degrees.
angExt - The angular extent of the arc in degrees.
closure - The closure type for the arc: OPEN, CHORD, or PIE.
Since:
1.2

setArc

public void setArc(Rectangle2D rect,
                   double angSt,
                   double angExt,
                   int closure)
Sets the location, size, angular extents, and closure type of this arc to the specified values.

Parameters:
rect - The framing rectangle that defines the outer boundary of the full ellipse of which this arc is a partial section.
angSt - The starting angle of the arc in degrees.
angExt - The angular extent of the arc in degrees.
closure - The closure type for the arc: OPEN, CHORD, or PIE.
Since:
1.2

setArc

public void setArc(Arc2D a)
Sets this arc to be the same as the specified arc.

Parameters:
a - The Arc2D to use to set the arc's values.
Since:
1.2

setArcByCenter

public void setArcByCenter(double x,
                           double y,
                           double radius,
                           double angSt,
                           double angExt,
                           int closure)
Sets the position, bounds, angular extents, and closure type of this arc to the specified values. The arc is defined by a center point and a radius rather than a framing rectangle for the full ellipse.

Parameters:
x - The X coordinate of the center of the arc.
y - The Y coordinate of the center of the arc.
radius - The radius of the arc.
angSt - The starting angle of the arc in degrees.
angExt - The angular extent of the arc in degrees.
closure - The closure type for the arc: OPEN, CHORD, or PIE.
Since:
1.2

setArcByTangent

public void setArcByTangent(Point2D p1,
                            Point2D p2,
                            Point2D p3,
                            double radius)
Sets the position, bounds, and angular extents of this arc to the specified value. The starting angle of the arc is tangent to the line specified by points (p1, p2), the ending angle is tangent to the line specified by points (p2, p3), and the arc has the specified radius.

Parameters:
p1 - The first point that defines the arc. The starting angle of the arc is tangent to the line specified by points (p1, p2).
p2 - The second point that defines the arc. The starting angle of the arc is tangent to the line specified by points (p1, p2). The ending angle of the arc is tangent to the line specified by points (p2, p3).
p3 - The third point that defines the arc. The ending angle of the arc is tangent to the line specified by points (p2, p3).
radius - The radius of the arc.
Since:
1.2

setAngleStart

public abstract void setAngleStart(double angSt)
Sets the starting angle of this arc to the specified double value.

Parameters:
angSt - The starting angle of the arc in degrees.
Since:
1.2
See Also:
getAngleStart()

setAngleExtent

public abstract void setAngleExtent(double angExt)
Sets the angular extent of this arc to the specified double value.

Parameters:
angExt - The angular extent of the arc in degrees.
Since:
1.2
See Also:
getAngleExtent()

setAngleStart

public void setAngleStart(Point2D p)
Sets the starting angle of this arc to the angle that the specified point defines relative to the center of this arc. The angular extent of the arc will remain the same.

Parameters:
p - The Point2D that defines the starting angle.
Since:
1.2
See Also:
getAngleStart()

setAngles

public void setAngles(double x1,
                      double y1,
                      double x2,
                      double y2)
Sets the starting angle and angular extent of this arc using two sets of coordinates. The first set of coordinates is used to determine the angle of the starting point relative to the arc's center. The second set of coordinates is used to determine the angle of the end point relative to the arc's center. The arc will always be non-empty and extend counterclockwise from the first point around to the second point.

Parameters:
x1 - The X coordinate of the arc's starting point.
y1 - The Y coordinate of the arc's starting point.
x2 - The X coordinate of the arc's ending point.
y2 - The Y coordinate of the arc's ending point.
Since:
1.2

setAngles

public void setAngles(Point2D p1,
                      Point2D p2)
Sets the starting angle and angular extent of this arc using two points. The first point is used to determine the angle of the starting point relative to the arc's center. The second point is used to determine the angle of the end point relative to the arc's center. The arc will always be non-empty and extend counterclockwise from the first point around to the second point.

Parameters:
p1 - The Point2D that defines the arc's starting point.
p2 - The Point2D that defines the arc's ending point.
Since:
1.2

setArcType

public void setArcType(int type)
Sets the closure type of this arc to the specified value: OPEN, CHORD, or PIE.

Parameters:
type - The integer constant that represents the closure type of this arc: OPEN, CHORD, or PIE.
Throws:
IllegalArgumentException - if type is not 0, 1, or 2.+
Since:
1.2
See Also:
getArcType()

setFrame

public void setFrame(double x,
                     double y,
                     double w,
                     double h)
Sets the location and size of the framing rectangle of this Shape to the specified rectangular values. Note that the arc partially inscribes the framing rectangle of this RectangularShape.

Specified by:
setFrame in class RectangularShape
Parameters:
x - the X coordinate of the upper-left corner of the specified rectangular shape
y - the Y coordinate of the upper-left corner of the specified rectangular shape
w - the width of the specified rectangular shape
h - the height of the specified rectangular shape
Since:
1.2
See Also:
RectangularShape.getFrame()

getBounds2D

public Rectangle2D getBounds2D()
Returns the high-precision framing rectangle of the arc. The framing rectangle contains only the part of this Arc2D that is in between the starting and ending angles and contains the pie wedge, if this Arc2D has a PIE closure type.

This method differs from the getBounds in that the getBounds method only returns the bounds of the enclosing ellipse of this Arc2D without considering the starting and ending angles of this Arc2D.

Returns:
the Rectangle2D that represents the arc's framing rectangle.
Since:
1.2
See Also:
Shape.getBounds()

makeBounds

protected abstract Rectangle2D makeBounds(double x,
                                          double y,
                                          double w,
                                          double h)
Constructs a Rectangle2D of the appropriate precision to hold the parameters calculated to be the framing rectangle of this arc.

Parameters:
x - The X coordinate of the upper-left corner of the framing rectangle.
y - The Y coordinate of the upper-left corner of the framing rectangle.
w - The width of the framing rectangle.
h - The height of the framing rectangle.
Returns:
a Rectangle2D that is the framing rectangle of this arc.
Since:
1.2

containsAngle

public boolean containsAngle(double angle)
Determines whether or not the specified angle is within the angular extents of the arc.

Parameters:
angle - The angle to test.
Returns:
true if the arc contains the angle, false if the arc doesn't contain the angle.
Since:
1.2

contains

public boolean contains(double x,
                        double y)
Determines whether or not the specified point is inside the boundary of the arc.

Parameters:
x - The X coordinate of the point to test.
y - The Y coordinate of the point to test.
Returns:
true if the point lies within the bound of the arc, false if the point lies outside of the arc's bounds.
Since:
1.2

intersects

public boolean intersects(double x,
                          double y,
                          double w,
                          double h)
Determines whether or not the interior of the arc intersects the interior of the specified rectangle.

Parameters:
x - The X coordinate of the rectangle's upper-left corner.
y - The Y coordinate of the rectangle's upper-left corner.
w - The width of the rectangle.
h - The height of the rectangle.
Returns:
true if the arc intersects the rectangle, false if the arc doesn't intersect the rectangle.
Since:
1.2
See Also:
Area

contains

public boolean contains(double x,
                        double y,
                        double w,
                        double h)
Determines whether or not the interior of the arc entirely contains the specified rectangle.

Parameters:
x - The X coordinate of the rectangle's upper-left corner.
y - The Y coordinate of the rectangle's upper-left corner.
w - The width of the rectangle.
h - The height of the rectangle.
Returns:
true if the arc contains the rectangle, false if the arc doesn't contain the rectangle.
Since:
1.2
See Also:
Area, Shape.intersects(double, double, double, double)

contains

public boolean contains(Rectangle2D r)
Determines whether or not the interior of the arc entirely contains the specified rectangle.

Specified by:
contains in interface Shape
Overrides:
contains in class RectangularShape
Parameters:
r - The Rectangle2D to test.
Returns:
true if the arc contains the rectangle, false if the arc doesn't contain the rectangle.
Since:
1.2
See Also:
Shape.contains(double, double, double, double)

getPathIterator

public PathIterator getPathIterator(AffineTransform at)
Returns an iteration object that defines the boundary of the arc. This iterator is multithread safe. Arc2D guarantees that modifications to the geometry of the arc do not affect any iterations of that geometry that are already in process.

Parameters:
at - an optional AffineTransform to be applied to the coordinates as they are returned in the iteration, or null if the untransformed coordinates are desired.
Returns:
A PathIterator that defines the arc's boundary.
Since:
1.2

hashCode

public int hashCode()
Returns the hashcode for this Arc2D.

Overrides:
hashCode in class Object
Returns:
the hashcode for this Arc2D.
Since:
1.6
See Also:
Object.equals(java.lang.Object), Hashtable

equals

public boolean equals(Object obj)
Determines whether or not the specified Object is equal to this Arc2D. The specified Object is equal to this Arc2D if it is an instance of Arc2D and if its location, size, arc extents and type are the same as this Arc2D.

Overrides:
equals in class Object
Parameters:
obj - an Object to be compared with this Arc2D.
Returns:
true if obj is an instance of Arc2D and has the same values; false otherwise.
Since:
1.6
See Also:
Object.hashCode(), Hashtable

Java™ Platform
Standard Ed. 6

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