java.awt.geom.Area
is new.
java.lang.Object
public class Area
An Area object stores and manipulates a resolution-independent description of an enclosed area of 2-dimensional 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 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.
The Area class implements the Shape interface and provides full support for all of its hit-testing and path iteration facilities, but an Area is more specific than a generalized path in a number of ways:
Only closed paths and sub-paths are stored. Area objects constructed from unclosed paths are implicitly closed during construction as if those paths had been filled by the Graphics2D.fill method.
The interiors of the individual stored sub-paths are all non-empty and non-overlapping. Paths are decomposed during construction into separate component non-overlapping parts, empty pieces of the path are discarded, and then these non-empty and non-overlapping properties are maintained through all subsequent CAG operations. Outlines of different component sub-paths 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 2-dimensional area, but may use entirely different types and ordering of the path segments to do so.
Interesting issues which are not always obvious when using the Area include:
Creating an Area from an unclosed (open) Shape results in a closed outline in the Area object.
Creating an 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.
A self-intersecting Shape may be split into two (or more) sub-paths each enclosing one of the non-intersecting 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 the Area 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 | |
|---|---|
|
Area
() Default constructor which creates an empty area. |
|
|
Area
(
Shape
s) 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 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
the Shape.
|
| boolean |
contains
(double x, double y, double w, double h) Tests
if
the Shape entirely
|
| boolean |
contains
(
Point2D
Tests if a specified Point2D |
| boolean |
contains
(
Rectangle2D
Tests
if
the Shape entirely
|
| 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 Shape
a
|
| boolean |
intersects
(
Rectangle2D
Tests
if
the Shape
a
|
| 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 . |
| Methods inherited from class java.lang. Object |
|---|
| equals , finalize , getClass , hashCode , notify , notifyAll , toString , wait , wait , wait |
| Constructor Detail |
|---|
public Area()
Since:
1.2
public Area(Shape s)
Since:
1.2
| Method Detail |
|---|
public void add(Area rhs)
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)
################ ################ ################
############## ############## ################
############ ############ ################
########## ########## ################
######## ######## ################
###### ###### ###### ######
#### #### #### ####
## ## ## ##
Since:
1.2
public void subtract(Area rhs)
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)
################ ################
############## ############## ##
############ ############ ####
########## ########## ######
######## ######## ########
###### ###### ######
#### #### ####
## ## ##
Since:
1.2
public void intersect(Area rhs)
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)
################ ################ ################
############## ############## ############
############ ############ ########
########## ########## ####
######## ########
###### ######
#### ####
## ##
Since:
1.2
public void exclusiveOr(Area rhs)
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)
################ ################
############## ############## ## ##
############ ############ #### ####
########## ########## ###### ######
######## ######## ################
###### ###### ###### ######
#### #### #### ####
## ## ## ##
Since:
1.2
public void reset()
Since:
1.2
public boolean isEmpty()
Since:
1.2
public boolean isPolygonal()
Since:
1.2
public boolean isRectangular()
Since:
1.2
public boolean isSingular()
Since:
1.2
public Rectangle2D getBounds2D()
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:
1.2
public Rectangle getBounds()
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.
Since:
1.2
public Object clone()
Since:
1.2
public boolean equals(Area other)
Since:
1.2
public void transform(AffineTransform t)
Since:
1.2
public Area createTransformedArea(AffineTransform t)
Since:
1.2
public boolean contains(double x,
double y)
Tests if the specified coordinates are inside the boundary of the Shape.
x - the specified X coordinate to be tested
y - the specified Y coordinate to be tested
true if the specified coordinates are inside the Shape boundary; false otherwise.
Since:
1.2
public boolean contains(Point2D p)
is
Shape.
specified
Point2D to
be tested
is inside
boundary
Shape;
Since:
1.2
public boolean contains(double x,
double y,
double w,
double h)
Tests if the interior of the 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:
the intersect method returns true and
the calculations to determine whether or not the Shape entirely contains the rectangular area are prohibitively expensive.
This means that for some 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.
x
X coordinate
upper-left
y - the Y coordinate of the upper-left corner of the specified rectangular area
true 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.
Since:
1.2
public boolean contains(Rectangle2D r)
Tests if the interior of the Shape entirely contains the specified Rectangle2D. The Shape.contains() method allows a Shape implementation to conservatively return false when:
the intersect method returns true and
the calculations to determine whether or not the Shape entirely contains the Rectangle2D are prohibitively expensive.
This means that for some 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.
The specified
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.
Since:
1.2
public 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. 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:
there is a high probability that the rectangular area and the Shape intersect, but
the calculations to accurately determine this intersection are prohibitively expensive.
This means that for some 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.
x
X coordinate
upper-left
y - the Y coordinate of the upper-left corner of the specified rectangular area
the
true 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.
Since:
1.2
public boolean intersects(Rectangle2D r)
Tests if the interior of the Shape intersects the interior of a specified Rectangle2D. The Shape.intersects() method allows a Shape implementation to conservatively return true when:
there is a high probability that the Rectangle2D and the Shape intersect, but
the calculations to accurately determine this intersection are prohibitively expensive.
This means that for some 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.
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.
Since:
1.2
public PathIterator getPathIterator(AffineTransform at)
Since:
1.2
public PathIterator getPathIterator(AffineTransform at,
double flatness)
end points
Since:
1.2