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:
Area
objects constructed from unclosed paths
are implicitly closed during construction as if those paths
had been filled by the Graphics2D.fill
method.
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:
Area
from an unclosed (open)
Shape
results in a closed outline in the
Area
object.
Area
from a Shape
which encloses no area (even when "closed") produces an
empty Area
. A common example of this issue
is that producing an Area
from a line will
be empty since the line encloses no area. An empty
Area
will iterate no geometry in its
PathIterator
objects.
Shape
may be split into
two (or more) subpaths each enclosing one of the
nonintersecting portions of the original path.
Area
may take more path segments to
describe the same geometry even when the original
outline is simple and obvious. The analysis that the
Area
class must perform on the path may
not reflect the same concepts of "simple and obvious"
as a human being perceives.
Constructor and Description 

Area()
Default constructor which creates an empty area.

Area(Shape s)
The
Area class creates an area geometry from the
specified Shape object. 
Modifier and Type  Method and Description 

void 
add(Area rhs)
Adds the shape of the specified
Area to the
shape of this Area . 
Object 
clone()
Returns an exact copy of this
Area object. 
boolean 
contains(double x,
double y)
Tests if the specified coordinates are inside the boundary of the
Shape , as described by the
definition of insideness. 
boolean 
contains(double x,
double y,
double w,
double h)
Tests if the interior of the
Shape entirely contains
the specified rectangular area. 
boolean 
contains(Point2D p)
Tests if a specified
Point2D is inside the boundary
of the Shape , as described by the
definition of insideness. 
boolean 
contains(Rectangle2D r)
Tests if the interior of the
Shape entirely contains the
specified Rectangle2D . 
Area 
createTransformedArea(AffineTransform t)
Creates a new
Area object that contains the same
geometry as this Area transformed by the specified
AffineTransform . 
boolean 
equals(Area other)
Tests whether the geometries of the two
Area objects
are equal. 
void 
exclusiveOr(Area rhs)
Sets the shape of this
Area to be the combined area
of its current shape and the shape of the specified Area ,
minus their intersection. 
Rectangle 
getBounds()
Returns a bounding
Rectangle that completely encloses
this Area . 
Rectangle2D 
getBounds2D()
Returns a high precision bounding
Rectangle2D that
completely encloses this Area . 
PathIterator 
getPathIterator(AffineTransform at)
Creates a
PathIterator for the outline of this
Area object. 
PathIterator 
getPathIterator(AffineTransform at,
double flatness)
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
its current shape and the shape of the specified Area . 
boolean 
intersects(double x,
double y,
double w,
double h)
Tests if the interior of the
Shape intersects the
interior of a specified rectangular area. 
boolean 
intersects(Rectangle2D r)
Tests if the interior of the
Shape intersects the
interior of a specified Rectangle2D . 
boolean 
isEmpty()
Tests whether this
Area object encloses any area. 
boolean 
isPolygonal()
Tests whether this
Area consists entirely of
straight edged polygonal geometry. 
boolean 
isRectangular()
Tests whether this
Area is rectangular in shape. 
boolean 
isSingular()
Tests whether this
Area is comprised of a single
closed subpath. 
void 
reset()
Removes all of the geometry from this
Area and
restores it to an empty area. 
void 
subtract(Area rhs)
Subtracts the shape of the specified
Area from the
shape of this Area . 
void 
transform(AffineTransform t)
Transforms the geometry of this
Area using the specified
AffineTransform . 
public Area()
public Area(Shape s)
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 (evenodd or winding) specified by the geometry of the
Shape
is used to determine the resulting enclosed area.s
 the Shape
from which the area is constructedNullPointerException
 if s
is nullpublic void add(Area rhs)
Area
to the
shape of this Area
.
The resulting shape of this Area
will include
the union of both shapes, or all areas that were contained
in either this or the specified Area
.
// 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) ################ ################ ################ ############## ############## ################ ############ ############ ################ ########## ########## ################ ######## ######## ################ ###### ###### ###### ###### #### #### #### #### ## ## ## ##
rhs
 the Area
to be added to the
current shapeNullPointerException
 if rhs
is nullpublic void subtract(Area rhs)
Area
from the
shape of this Area
.
The resulting shape of this Area
will include
areas that were contained only in this Area
and not in the specified Area
.
// 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) ################ ################ ############## ############## ## ############ ############ #### ########## ########## ###### ######## ######## ######## ###### ###### ###### #### #### #### ## ## ##
rhs
 the Area
to be subtracted from the
current shapeNullPointerException
 if rhs
is nullpublic void intersect(Area rhs)
Area
to the intersection of
its current shape and the shape of the specified Area
.
The resulting shape of this Area
will include
only areas that were contained in both this Area
and also in the specified Area
.
// 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) ################ ################ ################ ############## ############## ############ ############ ############ ######## ########## ########## #### ######## ######## ###### ###### #### #### ## ##
rhs
 the Area
to be intersected with this
Area
NullPointerException
 if rhs
is nullpublic void exclusiveOr(Area rhs)
Area
to be the combined area
of its current shape and the shape of the specified Area
,
minus their intersection.
The resulting shape of this Area
will include
only areas that were contained in either this Area
or in the specified Area
, 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) ################ ################ ############## ############## ## ## ############ ############ #### #### ########## ########## ###### ###### ######## ######## ################ ###### ###### ###### ###### #### #### #### #### ## ## ## ##
rhs
 the Area
to be exclusive ORed with this
Area
.NullPointerException
 if rhs
is nullpublic void reset()
Area
and
restores it to an empty area.public boolean isEmpty()
Area
object encloses any area.true
if this Area
object
represents an empty area; false
otherwise.public boolean isPolygonal()
Area
consists entirely of
straight edged polygonal geometry.true
if the geometry of this
Area
consists entirely of line segments;
false
otherwise.public boolean isRectangular()
Area
is rectangular in shape.true
if the geometry of this
Area
is rectangular in shape; false
otherwise.public boolean isSingular()
Area
is comprised of a single
closed subpath. This method returns true
if the
path contains 0 or 1 subpaths, or false
if the path
contains more than 1 subpath. The subpaths are counted by the
number of SEG_MOVETO
segments
that appear in the path.true
if the Area
is comprised
of a single basic geometry; false
otherwise.public Rectangle2D getBounds2D()
Rectangle2D
that
completely encloses this Area
.
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.
getBounds2D
in interface Shape
Rectangle2D
for the
Area
.Shape.getBounds()
public Rectangle getBounds()
Rectangle
that completely encloses
this Area
.
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.
getBounds
in interface Shape
Rectangle
for the
Area
.Shape.getBounds2D()
public Object clone()
Area
object.public boolean equals(Area other)
Area
objects
are equal.
This method will return false if the argument is null.other
 the Area
to be compared to this
Area
true
if the two geometries are equal;
false
otherwise.public void transform(AffineTransform t)
Area
using the specified
AffineTransform
. The geometry is transformed in place, which
permanently changes the enclosed area defined by this object.t
 the transformation used to transform the areaNullPointerException
 if t
is nullpublic Area createTransformedArea(AffineTransform t)
Area
object that contains the same
geometry as this Area
transformed by the specified
AffineTransform
. This Area
object
is unchanged.t
 the specified AffineTransform
used to transform
the new Area
Area
object representing the transformed
geometry.NullPointerException
 if t
is nullpublic boolean contains(double x, double y)
Shape
, as described by the
definition of insideness.public boolean contains(Point2D p)
Point2D
is inside the boundary
of the Shape
, as described by the
definition of insideness.public boolean contains(double x, double y, double w, double h)
Shape
entirely contains
the specified rectangular area. All coordinates that lie inside
the rectangular area must lie within the Shape
for the
entire rectanglar area to be considered contained within the
Shape
.
The Shape.contains()
method allows a Shape
implementation to conservatively return false
when:
intersect
method returns true
and
Shape
entirely contains the rectangular area are
prohibitively expensive.
Shapes
this method might
return false
even though the Shape
contains
the rectangular area.
The Area
class performs
more accurate geometric computations than most
Shape
objects and therefore can be used if a more precise
answer is required.contains
in interface Shape
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 areatrue
if the interior of the Shape
entirely contains the specified rectangular area;
false
otherwise or, if the Shape
contains the rectangular area and the
intersects
method returns true
and the containment calculations would be too expensive to
perform.Area
,
Shape.intersects(double, double, double, double)
public boolean contains(Rectangle2D r)
Shape
entirely contains the
specified Rectangle2D
.
The Shape.contains()
method allows a Shape
implementation to conservatively return false
when:
intersect
method returns true
and
Shape
entirely contains the Rectangle2D
are prohibitively expensive.
Shapes
this method might
return false
even though the Shape
contains
the Rectangle2D
.
The Area
class performs
more accurate geometric computations than most
Shape
objects and therefore can be used if a more precise
answer is required.contains
in interface Shape
r
 The specified Rectangle2D
true
if the interior of the Shape
entirely contains the Rectangle2D
;
false
otherwise or, if the Shape
contains the Rectangle2D
and the
intersects
method returns true
and the containment calculations would be too expensive to
perform.Shape.contains(double, double, double, double)
public boolean intersects(double x, double y, double w, double h)
Shape
intersects the
interior of a specified rectangular area.
The rectangular area is considered to intersect the Shape
if any point is contained in both the interior of the
Shape
and the specified rectangular area.
The Shape.intersects()
method allows a Shape
implementation to conservatively return true
when:
Shape
intersect, but
Shapes
this method might
return true
even though the rectangular area does not
intersect the Shape
.
The Area
class performs
more accurate computations of geometric intersection than most
Shape
objects and therefore can be used if a more precise
answer is required.intersects
in interface Shape
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 areatrue
if the interior of the Shape
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.Area
public boolean intersects(Rectangle2D r)
Shape
intersects the
interior of a specified Rectangle2D
.
The Shape.intersects()
method allows a Shape
implementation to conservatively return true
when:
Rectangle2D
and the
Shape
intersect, but
Shapes
this method might
return true
even though the Rectangle2D
does not
intersect the Shape
.
The Area
class performs
more accurate computations of geometric intersection than most
Shape
objects and therefore can be used if a more precise
answer is required.intersects
in interface Shape
r
 the specified Rectangle2D
true
if the interior of the Shape
and
the interior of the specified Rectangle2D
intersect, or are both highly likely to intersect and intersection
calculations would be too expensive to perform; false
otherwise.Shape.intersects(double, double, double, double)
public PathIterator getPathIterator(AffineTransform at)
getPathIterator
in interface Shape
at
 an optional AffineTransform
to be applied to
the coordinates as they are returned in the iteration, or
null
if untransformed coordinates are desiredPathIterator
object that returns the
geometry of the outline of this Area
, one
segment at a time.public PathIterator getPathIterator(AffineTransform at, double flatness)
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.getPathIterator
in interface Shape
at
 an optional AffineTransform
to be
applied to the coordinates as they are returned in the
iteration, or null
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 pointsPathIterator
object that returns the
geometry of the outline of this Area
, one segment
at a time.
For further API reference and developer documentation, see Java SE Documentation. That documentation contains more detailed, developertargeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples.
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