java.awt.geom
Class Area

java.lang.Object
  |
  +--java.awt.geom.Area

public class Area

extends Object

implements Shape, Cloneable

The Area class is a device-independent specification of an arbitrarily-shaped area. The Area object is defined as an object that performs certain binary CAG (Constructive Area Geometry) operations on other area-enclosing geometries, such as rectangles, ellipses, and polygons. The CAG operations are Add(union), Subtract, Intersect, and ExclusiveOR. For example, an Area can be made up of the area of a rectangle minus the area of an ellipse.

Constructor Summary

Area()
Default constructor which creates an empty area.

Area(Shape g)
The Area class creates an area geometry from the specified Shape object.

Method Summary

void	add(Area rhs) Adds the shape of the specified Area to the current shape.
Object	clone() clone function ...
boolean	contains(double x, double y) Tests if a specifed point lies inside the boundary of the shape.
boolean	contains(double x, double y, double w, double h) Tests whether or not the interior of the area completely contains the specified rectangular area.
boolean	contains(Point2D p) Tests if a specified Point2D lies inside the boundary of the shape.
boolean	contains(Rectangle2D r) Tests whether or not the interior of the area completely contains the specified Rectangle2D.
Area	createTransformedArea(AffineTransform t) Creates a new Area that is the geometry of this Area and transforms the new Area with the specified AffineTransform.
boolean	equals(Area rhs) Tests whether the two object's geometries are equal.
void	exclusiveOr(Area rhs) Sets the shape of this Area to be the combined area of the current shape and the shape of the specified Area, minus their intersection.
Rectangle	getBounds() Returns a bounding Rectangle that completely encloses the area.
Rectangle2D	getBounds2D() Returns a high precision bounding Rectangle2D that completely encloses the area.
PathIterator	getPathIterator(AffineTransform t) Creates a PathIterator for the outline of this Area object.
PathIterator	getPathIterator(AffineTransform t, double f) Creates a PathIterator for the flattened outline of this Area object.
void	intersect(Area rhs) Sets the shape of this Area to the intersection of the current shape and the shape of the specified Area.
boolean	intersects(double x, double y, double w, double h) Tests whether the interior of the area intersects the interior of the specified rectangular area.
boolean	intersects(Rectangle2D r) Tests whether the interior of the area intersects the interior of the specified Rectangle2D.
boolean	isEmpty() Tests whether this area contains any geometry.
boolean	isPolygonal() Tests whether the area consists entirely of straight edged polygonal geometry.
boolean	isRectangular() Tests whether the area is rectangular in shape.
boolean	isSingular() Tests whether the area is comprised of a single basic geometry.
void	reset() Removes all the basic geometry from this area and restores it to an empty area.
void	subtract(Area rhs) Subtracts the shape of the specified Area from the current shape.
void	transform(AffineTransform t) Transforms the geometry of this Area using the specified AffineTransform.

Methods inherited from class java.lang.Object

equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

Area

public Area()

Default constructor which creates an empty area.

Area

public Area(Shape g)

The Area class creates an area geometry from the specified Shape object. The geometry is explicitly closed, if the Shape is not already closed. The fill rule (even-odd or winding) specified by the geometry of the Shape is used to determine the resulting enclosed area.

Parameters:

g - the Shape from which the area is constructed

Method Detail

transform

public void transform(AffineTransform t)

Transforms the geometry of this Area using the specified AffineTransform. The geometry is transformed in place, which permanently changes the enclosed area defined by this object.

Parameters:

t - the matrix used to transform the area

reset

public void reset()

Removes all the basic geometry from this area and restores it to an empty area.

isEmpty

public boolean isEmpty()

Tests whether this area contains any geometry.

Returns:

true if this area contains no basic geometry, or is an empty area; false otherwise.

isPolygonal

public boolean isPolygonal()

Tests whether the area consists entirely of straight edged polygonal geometry.

Returns:

true if the area consists completely of polygon edges; false otherwise.

isRectangular

public boolean isRectangular()

Tests whether the area is rectangular in shape.

Returns:

true if the area is rectangular in shape; false otherwise.

isSingular

public boolean isSingular()

Tests whether the area is comprised of a single basic geometry.

Returns:

true if the area is comprised of a single basic geometry; false otherwise.

getBounds

public Rectangle getBounds()

Returns a bounding Rectangle that completely encloses the area.

Specified by:

getBounds in interface Shape

Returns:

the bounding Rectangle for the area.

getBounds2D

public Rectangle2D getBounds2D()

Returns a high precision bounding Rectangle2D that completely encloses the area.

Specified by:

getBounds2D in interface Shape

Returns:

the bounding Rectangle2D for the area.

intersects

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

Tests whether the interior of the area intersects the interior of the specified rectangular area.

Specified by:

intersects in interface Shape

Parameters:

x, y - the coordinates of the upper left corner of the specified rectangular area

w - the width of the specified rectangular area

h - the height of teh specified rectangular area

Returns:

true if the interior intersects the specified rectangular area; false otherwise;

intersects

public boolean intersects(Rectangle2D r)

Tests whether the interior of the area intersects the interior of the specified Rectangle2D.

Specified by:

intersects in interface Shape

Parameters:

r - the Rectangle2D to test for intersection

Returns:

true if the interior intersects the specified Rectangle2D; false otherwise.

contains

public boolean contains(double x,
                        double y)

Tests if a specifed point lies inside the boundary of the shape.

Specified by:

contains in interface Shape

Parameters:

x, y - the specified point

Returns:

true if the point lies completely within the interior of the area; false otherwise.

contains

public boolean contains(Point2D p)

Tests if a specified Point2D lies inside the boundary of the shape.

Specified by:

contains in interface Shape

Parameters:

p - the Point2D to test

Returns:

true if the specified Point2D lies completely within the interior of the area; false otherwise.

contains

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

Tests whether or not the interior of the area completely contains the specified rectangular area.

Specified by:

contains in interface Shape

Parameters:

x, y - the coordinates of the upper left corner of the specified rectangular area

w - the width of the specified rectangular area

h - the height of the specified rectangular area

Returns:

true if the specified rectangular area lies completely within the interior of the area; false otherwise.

contains

public boolean contains(Rectangle2D r)

Tests whether or not the interior of the area completely contains the specified Rectangle2D.

Specified by:

contains in interface Shape

Parameters:

r - the Rectangle2D to test

Returns:

true if the Rectangle2D lies completely within the interior of the area; false otherwise.

add

public void add(Area rhs)

Adds the shape of the specified Area to the current shape. Addition is achieved through union.

Parameters:

rhs - the Area to be added to the current shape

subtract

public void subtract(Area rhs)

Subtracts the shape of the specified Area from the current shape.

Parameters:

rhs - the Area to be subtracted from the current shape

intersect

public void intersect(Area rhs)

Sets the shape of this Area to the intersection of the current shape and the shape of the specified Area.

Parameters:

rhs - the Area to be intersected with this Area

exclusiveOr

public void exclusiveOr(Area rhs)

Sets the shape of this Area to be the combined area of the current shape and the shape of the specified Area, minus their intersection.

Parameters:

rhs - the Area to be exclusive ORed with this Area.

clone

public Object clone()

clone function ... to be compatible with Cloneable

Returns:

Created clone object

Overrides:

clone in class Object

equals

public boolean equals(Area rhs)

Tests whether the two object's geometries are equal.

Parameters:

rhs - the Area to be compared to this Area

Returns:

true if the two area geometries are equal; false otherwise.

getPathIterator

public PathIterator getPathIterator(AffineTransform t)

Creates a PathIterator for the outline of this Area object. This Area object is unchanged.

Specified by:

getPathIterator in interface Shape

Parameters:

t - an optional AffineTransform to be applied to the coordinates as they are returned in the iteration, or null if untransformed coordinates are desired

Returns:

the PathIterator object that returns the geometry of the outline of this Area, one segment at a time.

getPathIterator

public PathIterator getPathIterator(AffineTransform t,
                                    double f)

Creates a PathIterator for the flattened outline of this Area object. Only uncurved path segments represented by the SEG_MOVETO, SEG_LINETO, and SEG_CLOSE point types are returned by the iterator. This Area object is unchanged.

Specified by:

getPathIterator in interface Shape

Parameters:

t - an optional AffineTransform to be applied to the coordinates as they are returned in the iteration, or null if untransformed coordinates are desired

flatness - the maximum amount that the control points for a given curve can vary from colinear before a subdivided curve is replaced by a straight line connecting the endpoints

Returns:

the PathIterator object that returns the geometry of the outline of this Area, one segment at a time.

createTransformedArea

public Area createTransformedArea(AffineTransform t)

Creates a new Area that is the geometry of this Area and transforms the new Area with the specified AffineTransform. This Area object is unchanged.

Parameters:

t - the specified AffineTransform used to transform the new Area

Returns:

a new Area object representing the transformed geometry.