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java.awt.geom

Class Arc2D

java.lang.Object
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+--java.awt.geom.RectangularShape
   |
   +--java.awt.geom.Arc2D


public abstract class Arc2D

extends RectangularShape

This class represents all arcs (segments of an ellipse in 2-D space). The arcs are defined by starting angle and extent (arc length) in degrees, as opposed to radians (like the rest of Java), and can be open, chorded, or wedge shaped. The angles are skewed according to the ellipse, so that 45 degrees always points to the upper right corner (positive x, negative y) of the bounding rectangle. A positive extent draws a counterclockwise arc, and while the angle can be any value, the path iterator only traverses the first 360 degrees. Storage is up to the subclasses.

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Field Summary

static intCHORD

A closed arc with a single segment connecting the endpoints (a chord).
static intOPEN

An open arc, with no segment connecting the endpoints.
static intPIE

A closed arc with two segments, one from each endpoint, meeting at the center of the ellipse.

Constructor Summary

Arc2D(int type)

Create a new arc, with the specified closure type.

Method Summary

booleancontains(double x, double y)

Determines if the arc contains the given point.
booleancontains(double x, double y, double w, double h)

Tests if a given rectangle is contained in the area of the arc.
booleancontains(java.awt.geom.Rectangle2D r)

Tests if a given rectangle is contained in the area of the arc.
booleancontainsAngle(double a)

Tests if the given angle, in degrees, is included in the arc.
doublegetAngleExtent()

Get the extent angle of the arc in degrees.
doublegetAngleStart()

Get the starting angle of the arc in degrees.
intgetArcType()

Return the closure type of the arc.
java.awt.geom.Rectangle2DgetBounds2D()

Gets the bounds of the arc.
java.awt.geom.Point2DgetEndPoint()

Returns the ending point of the arc.
java.awt.geom.PathIteratorgetPathIterator(java.awt.geom.AffineTransform at)

Returns an iterator over this arc, with an optional transformation.
java.awt.geom.Point2DgetStartPoint()

Returns the starting point of the arc.
booleanintersects(double x, double y, double w, double h)

Tests if a given rectangle intersects the area of the arc.
java.awt.geom.Rectangle2DmakeBounds(double x, double y, double w, double h)

Construct a bounding box in a precision appropriate for the subclass.
voidsetAngleExtent(double extent)

Set the extent, in degrees.
voidsetAngleStart(double start)

Set the start, in degrees.
voidsetAngleStart(java.awt.geom.Point2D p)

Sets the starting angle to the angle of the given point relative to the center of the arc.
voidsetAngles(double x1, double y1, double x2, double y2)

Sets the starting and extent angles to those of the given points relative to the center of the arc.
voidsetAngles(java.awt.geom.Point2D p1, java.awt.geom.Point2D p2)

Sets the starting and extent angles to those of the given points relative to the center of the arc.
voidsetArc(double x, double y, double w, double h, double start, double extent, int type)

Set the parameters of the arc.
voidsetArc(java.awt.geom.Point2D p, java.awt.geom.Dimension2D d, double start, double extent, int type)

Set the parameters of the arc.
voidsetArc(java.awt.geom.Rectangle2D r, double start, double extent, int type)

Set the parameters of the arc.
voidsetArc(java.awt.geom.Arc2D a)

Set the parameters of the arc from the given one.
voidsetArcByCenter(double x, double y, double r, double start, double extent, int type)

Set the parameters of the arc.
voidsetArcByTangent(java.awt.geom.Point2D p1, java.awt.geom.Point2D p2, java.awt.geom.Point2D p3, double r)

Sets the parameters of the arc by finding the tangents of two lines, and using the specified radius.
voidsetArcType(int type)

Set the closure type of this arc.
voidsetFrame(double x, double y, double w, double h)

Sets the location and bounds of the ellipse of which this arc is a part.

Field Details

CHORD

public static final int CHORD

A closed arc with a single segment connecting the endpoints (a chord).


OPEN

public static final int OPEN

An open arc, with no segment connecting the endpoints. This type of arc still contains the same points as a chorded version.


PIE

public static final int PIE

A closed arc with two segments, one from each endpoint, meeting at the center of the ellipse.


Constructor Details

Arc2D

protected Arc2D(int type)

Create a new arc, with the specified closure type.

Parameters:

Throws:


Method Details

contains

public boolean contains(double x, double y)

Determines if the arc contains the given point. If the bounding box is empty, then this will return false.

Parameters:

Returns:


contains

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

Tests if a given rectangle is contained in the area of the arc.

Parameters:

Returns:


contains

public boolean contains(java.awt.geom.Rectangle2D r)

Tests if a given rectangle is contained in the area of the arc.

Parameters:

Returns:


containsAngle

public boolean containsAngle(double a)

Tests if the given angle, in degrees, is included in the arc. XXX Does this normalize all angles to -180 - 180 first?

Parameters:

Returns:


getAngleExtent

public double getAngleExtent()

Get the extent angle of the arc in degrees.

Returns:

See Also:


getAngleStart

public double getAngleStart()

Get the starting angle of the arc in degrees.

Returns:

See Also:


getArcType

public int getArcType()

Return the closure type of the arc.

Returns:

See Also:


getBounds2D

public Rectangle2D getBounds2D()

Gets the bounds of the arc. This is much tighter than getBounds, as it takes into consideration the start and end angles, and the center point of a pie wedge, rather than just the overall ellipse.

Returns:

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getEndPoint

public Point2D getEndPoint()

Returns the ending point of the arc.

Returns:


getPathIterator

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

Returns an iterator over this arc, with an optional transformation. This iterator is threadsafe, so future modifications to the arc do not affect the iteration.

Parameters:

Returns:


getStartPoint

public Point2D getStartPoint()

Returns the starting point of the arc.

Returns:


intersects

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

Tests if a given rectangle intersects the area of the arc.

Parameters:

Returns:


makeBounds

protected Rectangle2D makeBounds(double x, double y, double w, double h)

Construct a bounding box in a precision appropriate for the subclass.

Parameters:

Returns:


setAngleExtent

public void setAngleExtent(double extent)

Set the extent, in degrees.

Parameters:

See Also:


setAngleStart

public void setAngleStart(double start)

Set the start, in degrees.

Parameters:

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setAngleStart

public void setAngleStart(java.awt.geom.Point2D p)

Sets the starting angle to the angle of the given point relative to the center of the arc. The extent remains constant; in other words, this rotates the arc.

Parameters:

Throws:

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setAngles

public void setAngles(double x1, double y1, double x2, double y2)

Sets the starting and extent angles to those of the given points relative to the center of the arc. The arc will be non-empty, and will extend counterclockwise.

Parameters:

See Also:


setAngles

public void setAngles(java.awt.geom.Point2D p1, java.awt.geom.Point2D p2)

Sets the starting and extent angles to those of the given points relative to the center of the arc. The arc will be non-empty, and will extend counterclockwise.

Parameters:

Throws:

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setArc

public void setArc(double x, double y, double w, double h, double start, double extent, int type)

Set the parameters of the arc. The angles are in degrees, and a positive extent sweeps counterclockwise (from the positive x-axis to the negative y-axis).

Parameters:

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setArc

public void setArc(java.awt.geom.Arc2D a)

Set the parameters of the arc from the given one.

Parameters:

Throws:


setArc

public void setArc(java.awt.geom.Point2D p, java.awt.geom.Dimension2D d, double start, double extent, int type)

Set the parameters of the arc. The angles are in degrees, and a positive extent sweeps counterclockwise (from the positive x-axis to the negative y-axis).

Parameters:

Throws:


setArc

public void setArc(java.awt.geom.Rectangle2D r, double start, double extent, int type)

Set the parameters of the arc. The angles are in degrees, and a positive extent sweeps counterclockwise (from the positive x-axis to the negative y-axis).

Parameters:

Throws:


setArcByCenter

public void setArcByCenter(double x, double y, double r, double start, double extent, int type)

Set the parameters of the arc. The angles are in degrees, and a positive extent sweeps counterclockwise (from the positive x-axis to the negative y-axis). This controls the center point and radius, so the arc will be circular.

Parameters:

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setArcByTangent

public void setArcByTangent(java.awt.geom.Point2D p1, java.awt.geom.Point2D p2, java.awt.geom.Point2D p3, double r)

Sets the parameters of the arc by finding the tangents of two lines, and using the specified radius. The arc will be circular, will begin on the tangent point of the line extending from p1 to p2, and will end on the tangent point of the line extending from p2 to p3. XXX What happens if the points are colinear, or the radius negative?

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setArcType

public void setArcType(int type)

Set the closure type of this arc.

Parameters:

Throws:

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setFrame

public void setFrame(double x, double y, double w, double h)

Sets the location and bounds of the ellipse of which this arc is a part.

Parameters:

See Also: