java.awt.geom

Class Arc2D

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

Implemented Interfaces:: Cloneable, Shape

Known Direct Subclasses:: Arc2D.Double, Arc2D.Float

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.

Since:: 1.2

Nested Class Summary
`static class`	`Arc2D.Double` This class implements an arc in double precision.
`static class`	`Arc2D.Float` This class implements an arc in float precision.

Field Summary
`static int`	`CHORD` A closed arc with a single segment connecting the endpoints (a chord).
`static int`	`OPEN` An open arc, with no segment connecting the endpoints.
`static int`	`PIE` 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
`boolean`	`contains(double x, double y)` Determines if the arc contains the given point.
`boolean`	`contains(double x, double y, double w, double h)` Tests if a given rectangle is contained in the area of the arc.
`boolean`	`contains(Rectangle2D r)` Tests if a given rectangle is contained in the area of the arc.
`boolean`	`containsAngle(double a)` Tests if the given angle, in degrees, is included in the arc.
`abstract double`	`getAngleExtent()` Get the extent angle of the arc in degrees.
`abstract double`	`getAngleStart()` Get the starting angle of the arc in degrees.
`int`	`getArcType()` Return the closure type of the arc.
`Rectangle2D`	`getBounds2D()` Gets the bounds of the arc.
`Point2D`	`getEndPoint()` Returns the ending point of the arc.
`PathIterator`	`getPathIterator(AffineTransform at)` Returns an iterator over this arc, with an optional transformation.
`Point2D`	`getStartPoint()` Returns the starting point of the arc.
`boolean`	`intersects(double x, double y, double w, double h)` Tests if a given rectangle intersects the area of the arc.
`protected abstract Rectangle2D`	`makeBounds(double x, double y, double w, double h)` Construct a bounding box in a precision appropriate for the subclass.
`abstract void`	`setAngleExtent(double extent)` Set the extent, in degrees.
`abstract void`	`setAngleStart(double start)` Set the start, in degrees.
`void`	`setAngleStart(Point2D p)` Sets the starting angle to the angle of the given point relative to the center of the arc.
`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.
`void`	`setAngles(Point2D p1, Point2D p2)` Sets the starting and extent angles to those of the given points relative to the center of the arc.
`abstract void`	`setArc(double x, double y, double w, double h, double start, double extent, int type)` Set the parameters of the arc.
`void`	`setArc(Arc2D a)` Set the parameters of the arc from the given one.
`void`	`setArc(Point2D p, Dimension2D d, double start, double extent, int type)` Set the parameters of the arc.
`void`	`setArc(Rectangle2D r, double start, double extent, int type)` Set the parameters of the arc.
`void`	`setArcByCenter(double x, double y, double r, double start, double extent, int type)` Set the parameters of the arc.
`void`	`setArcByTangent(Point2D p1, Point2D p2, Point2D p3, double r)` Sets the parameters of the arc by finding the tangents of two lines, and using the specified radius.
`void`	`setArcType(int type)` Set the closure type of this arc.
`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.

Methods inherited from class java.awt.geom.RectangularShape
`clone`, `contains`, `contains`, `getBounds`, `getCenterX`, `getCenterY`, `getFrame`, `getHeight`, `getMaxX`, `getMaxY`, `getMinX`, `getMinY`, `getPathIterator`, `getWidth`, `getX`, `getY`, `intersects`, `isEmpty`, `setFrame`, `setFrame`, `setFrame`, `setFrameFromCenter`, `setFrameFromCenter`, `setFrameFromDiagonal`, `setFrameFromDiagonal`

Methods inherited from class java.lang.Object
`clone`, `equals`, `extends Object> getClass`, `finalize`, `hashCode`, `notify`, `notifyAll`, `toString`, `wait`, `wait`, `wait`

CHORD

public static final int CHORD

A closed arc with a single segment connecting the endpoints (a chord).
Field Value:
1

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.
Field Value:
0

PIE

public static final int PIE

A closed arc with two segments, one from each endpoint, meeting at the center of the ellipse.
Field Value:
2

Arc2D

protected Arc2D(int type)

Create a new arc, with the specified closure type.
Parameters:
type - one of OPEN, CHORD, or PIE.
Throws:
IllegalArgumentException - if type is invalid

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. The area considered 'inside' an arc of type OPEN is the same as the area inside an equivalent filled CHORD-type arc. The area considered 'inside' a CHORD-type arc is the same as the filled area.
Specified by:
contains in interface Shape
Parameters:
x - the x coordinate to test
y - the y coordinate to test
Returns:
true if the point is inside the arc

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.
Specified by:
contains in interface Shape
Parameters:
x - the x coordinate of the rectangle
y - the y coordinate of the rectangle
w - the width of the rectangle
h - the height of the rectangle
Returns:
true if the arc contains the rectangle

contains

public boolean contains(Rectangle2D r)

Tests if a given rectangle is contained in the area of the arc.
Specified by:
contains in interface Shape
Overrides:
contains in interface RectangularShape
Parameters:
r - the rectangle
Returns:
true if the arc contains the rectangle

containsAngle

public boolean containsAngle(double a)

Tests if the given angle, in degrees, is included in the arc. All angles are normalized to be between 0 and 360 degrees.
Parameters:
a - the angle to test
Returns:
true if it is contained

getAngleExtent

public abstract double getAngleExtent()

Get the extent angle of the arc in degrees.
Returns:
the extent angle
See Also:
setAngleExtent(double)

getAngleStart

public abstract double getAngleStart()

Get the starting angle of the arc in degrees.
Returns:
the starting angle
See Also:
setAngleStart(double)

getArcType

public int getArcType()

Return the closure type of the arc.
Returns:
the closure type
See Also:
OPEN, CHORD, PIE, setArcType(int)

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.
Specified by:
getBounds2D in interface Shape
Returns:
the bounds of the arc
See Also:
getBounds()

getEndPoint

public Point2D getEndPoint()

Returns the ending point of the arc.
Returns:
the end point

getPathIterator

public PathIterator getPathIterator(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.
Specified by:
getPathIterator in interface Shape
Parameters:
at - the transformation, or null
Returns:
a path iterator

getStartPoint

public Point2D getStartPoint()

Returns the starting point of the arc.
Returns:
the start point

intersects

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

Tests if a given rectangle intersects the area of the arc. For a definition of the 'inside' area, see the contains() method.
Specified by:
intersects in interface Shape
Parameters:
x - the x coordinate of the rectangle
y - the y coordinate of the rectangle
w - the width of the rectangle
h - the height of the rectangle
Returns:
true if the two shapes share common points
See Also:
contains(double,double)

makeBounds

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

Construct a bounding box in a precision appropriate for the subclass.
Parameters:
x - the x coordinate
y - the y coordinate
w - the width
h - the height
Returns:
the rectangle for use in getBounds2D

setAngleExtent

public abstract void setAngleExtent(double extent)

Set the extent, in degrees.
Parameters:
extent - the new extent angle
See Also:
getAngleExtent()

setAngleStart

public abstract void setAngleStart(double start)

Set the start, in degrees.
Parameters:
start - the new start angle
See Also:
getAngleStart()

setAngleStart

public void setAngleStart(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:
p - the new start point
Throws:
NullPointerException - if p is null
See Also:
getStartPoint(), getAngleStart()

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:
x1 - the first x coordinate
y1 - the first y coordinate
x2 - the second x coordinate
y2 - the second y coordinate
See Also:
setAngleStart(Point2D)

setAngles

public void setAngles(Point2D p1,
                      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:
p1 - the first point
p2 - the second point
Throws:
NullPointerException - if either point is null
See Also:
setAngleStart(Point2D)

setArc

public abstract 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:
x - the new x coordinate of the upper left of the bounding box
y - the new y coordinate of the upper left of the bounding box
w - the new width of the bounding box
h - the new height of the bounding box
start - the start angle, in degrees
extent - the arc extent, in degrees
type - one of OPEN, CHORD, or PIE
Throws:
IllegalArgumentException - if type is invalid

setArc

public void setArc(Arc2D a)

Set the parameters of the arc from the given one.
Parameters:
a - the arc to copy
Throws:
NullPointerException - if a is null

setArc

public void setArc(Point2D p,
                   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:
p - the upper left point of the bounding box
d - the dimensions of the bounding box
start - the start angle, in degrees
extent - the arc extent, in degrees
type - one of OPEN, CHORD, or PIE
Throws:
IllegalArgumentException - if type is invalid
NullPointerException - if p or d is null

setArc

public void setArc(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:
r - the new bounding box
start - the start angle, in degrees
extent - the arc extent, in degrees
type - one of OPEN, CHORD, or PIE
Throws:
IllegalArgumentException - if type is invalid
NullPointerException - if r is null

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:
x - the x coordinate of the center of the circle
y - the y coordinate of the center of the circle
r - the radius of the circle
start - the start angle, in degrees
extent - the arc extent, in degrees
type - one of OPEN, CHORD, or PIE
Throws:
IllegalArgumentException - if type is invalid

setArcByTangent

public void setArcByTangent(Point2D p1,
                            Point2D p2,
                            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?
Parameters:
p1 - the first point
p2 - the tangent line intersection point
p3 - the third point
r - the radius of the arc
Throws:
NullPointerException - if any point is null

setArcType

public void setArcType(int type)

Set the closure type of this arc.
Parameters:
type - one of OPEN, CHORD, or PIE
Throws:
IllegalArgumentException - if type is invalid
See Also:
getArcType()

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.
Overrides:
setFrame in interface RectangularShape
Parameters:
x - the new x coordinate
y - the new y coordinate
w - the new width
h - the new height
See Also:
getFrame()

Arc2D.java -- represents an arc in 2-D space Copyright (C) 2002, 2003, 2004 Free Software Foundation This file is part of GNU Classpath. GNU Classpath is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2, or (at your option) any later version. GNU Classpath is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with GNU Classpath; see the file COPYING. If not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. Linking this library statically or dynamically with other modules is making a combined work based on this library. Thus, the terms and conditions of the GNU General Public License cover the whole combination. As a special exception, the copyright holders of this library give you permission to link this library with independent modules to produce an executable, regardless of the license terms of these independent modules, and to copy and distribute the resulting executable under terms of your choice, provided that you also meet, for each linked independent module, the terms and conditions of the license of that module. An independent module is a module which is not derived from or based on this library. If you modify this library, you may extend this exception to your version of the library, but you are not obligated to do so. If you do not wish to do so, delete this exception statement from your version.

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java.awt.geom

Class Arc2D

Nested Class Summary

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.awt.geom.RectangularShape

Methods inherited from class java.lang.Object

Field Details

CHORD

OPEN

PIE

Constructor Details

Arc2D

Method Details

contains

contains

contains

containsAngle

getAngleExtent

getAngleStart

getArcType

getBounds2D

getEndPoint

getPathIterator

getStartPoint

intersects

makeBounds

setAngleExtent

setAngleStart

setAngleStart

setAngles

setAngles

setArc

setArc

setArc

setArc

setArcByCenter

setArcByTangent

setArcType

setFrame