public class Area extends Object implements Shape, Cloneable
Area
object stores and manipulates a
resolutionindependent description of an enclosed area of
2dimensional space.
Area
objects can be transformed and can perform
various Constructive Area Geometry (CAG) operations when combined
with other Area
objects.
The CAG operations include area
addition
, subtraction
,
intersection
, and exclusive or
.
See the linked method documentation for examples of the various
operations.
The Area
class implements the Shape
interface and provides full support for all of its hittesting
and path iteration facilities, but an Area
is more
specific than a generalized path in a number of ways:
 Only closed paths and subpaths are stored.
Area
objects constructed from unclosed paths are implicitly closed during construction as if those paths had been filled by theGraphics2D.fill
method.  The interiors of the individual stored subpaths are all nonempty and nonoverlapping. Paths are decomposed during construction into separate component nonoverlapping parts, empty pieces of the path are discarded, and then these nonempty and nonoverlapping properties are maintained through all subsequent CAG operations. Outlines of different component subpaths may touch each other, as long as they do not cross so that their enclosed areas overlap.
 The geometry of the path describing the outline of the
Area
resembles the path from which it was constructed only in that it describes the same enclosed 2dimensional area, but may use entirely different types and ordering of the path segments to do so.
Area
include:
 Creating an
Area
from an unclosed (open)Shape
results in a closed outline in theArea
object.  Creating an
Area
from aShape
which encloses no area (even when "closed") produces an emptyArea
. A common example of this issue is that producing anArea
from a line will be empty since the line encloses no area. An emptyArea
will iterate no geometry in itsPathIterator
objects.  A selfintersecting
Shape
may be split into two (or more) subpaths each enclosing one of the nonintersecting portions of the original path.  An
Area
may take more path segments to describe the same geometry even when the original outline is simple and obvious. The analysis that theArea
class must perform on the path may not reflect the same concepts of "simple and obvious" as a human being perceives.
 Since:
 1.2

Constructor Summary

Method Summary
Modifier and Type Method Description void
add(Area rhs)
Adds the shape of the specifiedArea
to the shape of thisArea
.Object
clone()
Returns an exact copy of thisArea
object.boolean
contains(double x, double y)
Tests if the specified coordinates are inside the boundary of theShape
, as described by the definition of insideness.boolean
contains(double x, double y, double w, double h)
Tests if the interior of theShape
entirely contains the specified rectangular area.boolean
contains(Point2D p)
Tests if a specifiedPoint2D
is inside the boundary of theShape
, as described by the definition of insideness.boolean
contains(Rectangle2D r)
Tests if the interior of theShape
entirely contains the specifiedRectangle2D
.Area
createTransformedArea(AffineTransform t)
Creates a newArea
object that contains the same geometry as thisArea
transformed by the specifiedAffineTransform
.boolean
equals(Area other)
Tests whether the geometries of the twoArea
objects are equal.void
exclusiveOr(Area rhs)
Sets the shape of thisArea
to be the combined area of its current shape and the shape of the specifiedArea
, minus their intersection.Rectangle
getBounds()
Returns a boundingRectangle
that completely encloses thisArea
.Rectangle2D
getBounds2D()
Returns a high precision boundingRectangle2D
that completely encloses thisArea
.PathIterator
getPathIterator(AffineTransform at)
Creates aPathIterator
for the outline of thisArea
object.PathIterator
getPathIterator(AffineTransform at, double flatness)
Creates aPathIterator
for the flattened outline of thisArea
object.void
intersect(Area rhs)
Sets the shape of thisArea
to the intersection of its current shape and the shape of the specifiedArea
.boolean
intersects(double x, double y, double w, double h)
Tests if the interior of theShape
intersects the interior of a specified rectangular area.boolean
intersects(Rectangle2D r)
Tests if the interior of theShape
intersects the interior of a specifiedRectangle2D
.boolean
isEmpty()
Tests whether thisArea
object encloses any area.boolean
isPolygonal()
Tests whether thisArea
consists entirely of straight edged polygonal geometry.boolean
isRectangular()
Tests whether thisArea
is rectangular in shape.boolean
isSingular()
Tests whether thisArea
is comprised of a single closed subpath.void
reset()
Removes all of the geometry from thisArea
and restores it to an empty area.void
subtract(Area rhs)
Subtracts the shape of the specifiedArea
from the shape of thisArea
.void
transform(AffineTransform t)
Transforms the geometry of thisArea
using the specifiedAffineTransform
.

Constructor Details

Area
public Area()Default constructor which creates an empty area. Since:
 1.2

Area
TheArea
class creates an area geometry from the specifiedShape
object. The geometry is explicitly closed, if theShape
is not already closed. The fill rule (evenodd or winding) specified by the geometry of theShape
is used to determine the resulting enclosed area. Parameters:
s
 theShape
from which the area is constructed Throws:
NullPointerException
 ifs
is null Since:
 1.2


Method Details

add
Adds the shape of the specifiedArea
to the shape of thisArea
. The resulting shape of thisArea
will include the union of both shapes, or all areas that were contained in either this or the specifiedArea
.// Example: Area a1 = new Area([triangle 0,0 => 8,0 => 0,8]); Area a2 = new Area([triangle 0,0 => 8,0 => 8,8]); a1.add(a2); a1(before) + a2 = a1(after) ################ ################ ################ ############## ############## ################ ############ ############ ################ ########## ########## ################ ######## ######## ################ ###### ###### ###### ###### #### #### #### #### ## ## ## ##
 Parameters:
rhs
 theArea
to be added to the current shape Throws:
NullPointerException
 ifrhs
is null Since:
 1.2

subtract
Subtracts the shape of the specifiedArea
from the shape of thisArea
. The resulting shape of thisArea
will include areas that were contained only in thisArea
and not in the specifiedArea
.// Example: Area a1 = new Area([triangle 0,0 => 8,0 => 0,8]); Area a2 = new Area([triangle 0,0 => 8,0 => 8,8]); a1.subtract(a2); a1(before)  a2 = a1(after) ################ ################ ############## ############## ## ############ ############ #### ########## ########## ###### ######## ######## ######## ###### ###### ###### #### #### #### ## ## ##
 Parameters:
rhs
 theArea
to be subtracted from the current shape Throws:
NullPointerException
 ifrhs
is null Since:
 1.2

intersect
Sets the shape of thisArea
to the intersection of its current shape and the shape of the specifiedArea
. The resulting shape of thisArea
will include only areas that were contained in both thisArea
and also in the specifiedArea
.// Example: Area a1 = new Area([triangle 0,0 => 8,0 => 0,8]); Area a2 = new Area([triangle 0,0 => 8,0 => 8,8]); a1.intersect(a2); a1(before) intersect a2 = a1(after) ################ ################ ################ ############## ############## ############ ############ ############ ######## ########## ########## #### ######## ######## ###### ###### #### #### ## ##
 Parameters:
rhs
 theArea
to be intersected with thisArea
 Throws:
NullPointerException
 ifrhs
is null Since:
 1.2

exclusiveOr
Sets the shape of thisArea
to be the combined area of its current shape and the shape of the specifiedArea
, minus their intersection. The resulting shape of thisArea
will include only areas that were contained in either thisArea
or in the specifiedArea
, but not in both.// Example: Area a1 = new Area([triangle 0,0 => 8,0 => 0,8]); Area a2 = new Area([triangle 0,0 => 8,0 => 8,8]); a1.exclusiveOr(a2); a1(before) xor a2 = a1(after) ################ ################ ############## ############## ## ## ############ ############ #### #### ########## ########## ###### ###### ######## ######## ################ ###### ###### ###### ###### #### #### #### #### ## ## ## ##
 Parameters:
rhs
 theArea
to be exclusive ORed with thisArea
. Throws:
NullPointerException
 ifrhs
is null Since:
 1.2

reset
public void reset()Removes all of the geometry from thisArea
and restores it to an empty area. Since:
 1.2

isEmpty
public boolean isEmpty()Tests whether thisArea
object encloses any area. Returns:
true
if thisArea
object represents an empty area;false
otherwise. Since:
 1.2

isPolygonal
public boolean isPolygonal()Tests whether thisArea
consists entirely of straight edged polygonal geometry. Returns:
true
if the geometry of thisArea
consists entirely of line segments;false
otherwise. Since:
 1.2

isRectangular
public boolean isRectangular()Tests whether thisArea
is rectangular in shape. Returns:
true
if the geometry of thisArea
is rectangular in shape;false
otherwise. Since:
 1.2

isSingular
public boolean isSingular()Tests whether thisArea
is comprised of a single closed subpath. This method returnstrue
if the path contains 0 or 1 subpaths, orfalse
if the path contains more than 1 subpath. The subpaths are counted by the number ofSEG_MOVETO
segments that appear in the path. Returns:
true
if theArea
is comprised of a single basic geometry;false
otherwise. Since:
 1.2

getBounds2D
Returns a high precision boundingRectangle2D
that completely encloses thisArea
.The Area class will attempt to return the tightest bounding box possible for the Shape. The bounding box will not be padded to include the control points of curves in the outline of the Shape, but should tightly fit the actual geometry of the outline itself.
 Specified by:
getBounds2D
in interfaceShape
 Returns:
 the bounding
Rectangle2D
for theArea
.  Since:
 1.2
 See Also:
Shape.getBounds()

getBounds
Returns a boundingRectangle
that completely encloses thisArea
.The Area class will attempt to return the tightest bounding box possible for the Shape. The bounding box will not be padded to include the control points of curves in the outline of the Shape, but should tightly fit the actual geometry of the outline itself. Since the returned object represents the bounding box with integers, the bounding box can only be as tight as the nearest integer coordinates that encompass the geometry of the Shape.
 Specified by:
getBounds
in interfaceShape
 Returns:
 the bounding
Rectangle
for theArea
.  Since:
 1.2
 See Also:
Shape.getBounds2D()

clone
Returns an exact copy of thisArea
object. 
equals
Tests whether the geometries of the twoArea
objects are equal. This method will return false if the argument is null. Parameters:
other
 theArea
to be compared to thisArea
 Returns:
true
if the two geometries are equal;false
otherwise. Since:
 1.2

transform
Transforms the geometry of thisArea
using the specifiedAffineTransform
. The geometry is transformed in place, which permanently changes the enclosed area defined by this object. Parameters:
t
 the transformation used to transform the area Throws:
NullPointerException
 ift
is null Since:
 1.2

createTransformedArea
Creates a newArea
object that contains the same geometry as thisArea
transformed by the specifiedAffineTransform
. ThisArea
object is unchanged. Parameters:
t
 the specifiedAffineTransform
used to transform the newArea
 Returns:
 a new
Area
object representing the transformed geometry.  Throws:
NullPointerException
 ift
is null Since:
 1.2

contains
public boolean contains(double x, double y)Tests if the specified coordinates are inside the boundary of theShape
, as described by the definition of insideness. 
contains
Tests if a specifiedPoint2D
is inside the boundary of theShape
, as described by the definition of insideness. 
contains
public boolean contains(double x, double y, double w, double h)Tests if the interior of theShape
entirely contains the specified rectangular area. All coordinates that lie inside the rectangular area must lie within theShape
for the entire rectangular area to be considered contained within theShape
.The
Shape.contains()
method allows aShape
implementation to conservatively returnfalse
when:
the
intersect
method returnstrue
and 
the calculations to determine whether or not the
Shape
entirely contains the rectangular area are prohibitively expensive.
Shapes
this method might returnfalse
even though theShape
contains the rectangular area. TheArea
class performs more accurate geometric computations than mostShape
objects and therefore can be used if a more precise answer is required. Specified by:
contains
in interfaceShape
 Parameters:
x
 the X coordinate of the upperleft corner of the specified rectangular areay
 the Y coordinate of the upperleft corner of the specified rectangular areaw
 the width of the specified rectangular areah
 the height of the specified rectangular area Returns:
true
if the interior of theShape
entirely contains the specified rectangular area;false
otherwise or, if theShape
contains the rectangular area and theintersects
method returnstrue
and the containment calculations would be too expensive to perform. Since:
 1.2
 See Also:
Area
,Shape.intersects(double, double, double, double)

the

contains
Tests if the interior of theShape
entirely contains the specifiedRectangle2D
. TheShape.contains()
method allows aShape
implementation to conservatively returnfalse
when:
the
intersect
method returnstrue
and 
the calculations to determine whether or not the
Shape
entirely contains theRectangle2D
are prohibitively expensive.
Shapes
this method might returnfalse
even though theShape
contains theRectangle2D
. TheArea
class performs more accurate geometric computations than mostShape
objects and therefore can be used if a more precise answer is required. Specified by:
contains
in interfaceShape
 Parameters:
r
 The specifiedRectangle2D
 Returns:
true
if the interior of theShape
entirely contains theRectangle2D
;false
otherwise or, if theShape
contains theRectangle2D
and theintersects
method returnstrue
and the containment calculations would be too expensive to perform. Since:
 1.2
 See Also:
Shape.contains(double, double, double, double)

the

intersects
public boolean intersects(double x, double y, double w, double h)Tests if the interior of theShape
intersects the interior of a specified rectangular area. The rectangular area is considered to intersect theShape
if any point is contained in both the interior of theShape
and the specified rectangular area.The
Shape.intersects()
method allows aShape
implementation to conservatively returntrue
when:
there is a high probability that the rectangular area and the
Shape
intersect, but  the calculations to accurately determine this intersection are prohibitively expensive.
Shapes
this method might returntrue
even though the rectangular area does not intersect theShape
. TheArea
class performs more accurate computations of geometric intersection than mostShape
objects and therefore can be used if a more precise answer is required. Specified by:
intersects
in interfaceShape
 Parameters:
x
 the X coordinate of the upperleft corner of the specified rectangular areay
 the Y coordinate of the upperleft corner of the specified rectangular areaw
 the width of the specified rectangular areah
 the height of the specified rectangular area Returns:
true
if the interior of theShape
and the interior of the rectangular area intersect, or are both highly likely to intersect and intersection calculations would be too expensive to perform;false
otherwise. Since:
 1.2
 See Also:
Area

there is a high probability that the rectangular area and the

intersects
Tests if the interior of theShape
intersects the interior of a specifiedRectangle2D
. TheShape.intersects()
method allows aShape
implementation to conservatively returntrue
when:
there is a high probability that the
Rectangle2D
and theShape
intersect, but  the calculations to accurately determine this intersection are prohibitively expensive.
Shapes
this method might returntrue
even though theRectangle2D
does not intersect theShape
. TheArea
class performs more accurate computations of geometric intersection than mostShape
objects and therefore can be used if a more precise answer is required. Specified by:
intersects
in interfaceShape
 Parameters:
r
 the specifiedRectangle2D
 Returns:
true
if the interior of theShape
and the interior of the specifiedRectangle2D
intersect, or are both highly likely to intersect and intersection calculations would be too expensive to perform;false
otherwise. Since:
 1.2
 See Also:
Shape.intersects(double, double, double, double)

there is a high probability that the

getPathIterator
 Specified by:
getPathIterator
in interfaceShape
 Parameters:
at
 an optionalAffineTransform
to be applied to the coordinates as they are returned in the iteration, ornull
if untransformed coordinates are desired Returns:
 the
PathIterator
object that returns the geometry of the outline of thisArea
, one segment at a time.  Since:
 1.2

getPathIterator
Creates aPathIterator
for the flattened outline of thisArea
object. Only uncurved path segments represented by the SEG_MOVETO, SEG_LINETO, and SEG_CLOSE point types are returned by the iterator. ThisArea
object is unchanged. Specified by:
getPathIterator
in interfaceShape
 Parameters:
at
 an optionalAffineTransform
to be applied to the coordinates as they are returned in the iteration, ornull
if untransformed coordinates are desiredflatness
 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 end points Returns:
 the
PathIterator
object that returns the geometry of the outline of thisArea
, one segment at a time.  Since:
 1.2
