Area (Java Platform SE 8 ) (original) (raw)

java.lang.Object
- java.awt.geom.Area
All Implemented Interfaces:
Shape, Cloneable

public class Area
extends Object
implements Shape, Cloneable
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 areaaddition, 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 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 theArea 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 theArea 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 emptyArea will iterate no geometry in itsPathIterator 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 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

Constructors

Constructor	Description
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

All Methods Instance Methods Concrete Methods

Modifier and Type	Method	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 theShape, 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 specifiedAffineTransform.
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 thisArea 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 specifiedAffineTransform.

   * ### Methods inherited from class java.lang.[Object](../../../java/lang/Object.html "class in java.lang")  
   `[equals](../../../java/lang/Object.html#equals-java.lang.Object-), [finalize](../../../java/lang/Object.html#finalize--), [getClass](../../../java/lang/Object.html#getClass--), [hashCode](../../../java/lang/Object.html#hashCode--), [notify](../../../java/lang/Object.html#notify--), [notifyAll](../../../java/lang/Object.html#notifyAll--), [toString](../../../java/lang/Object.html#toString--), [wait](../../../java/lang/Object.html#wait--), [wait](../../../java/lang/Object.html#wait-long-), [wait](../../../java/lang/Object.html#wait-long-int-)`

Constructor Detail

 * #### Area  
 public Area()  
 Default constructor which creates an empty area.  
 Since:  
 1.2  
 * #### Area  
 public Area([Shape](../../../java/awt/Shape.html "interface in java.awt") s)  
 The `Area` class creates an area geometry from the specified [Shape](../../../java/awt/Shape.html "interface in java.awt") 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:  
 `s` \- the `Shape` from which the area is constructed  
 Throws:  
 `[NullPointerException](../../../java/lang/NullPointerException.html "class in java.lang")` \- if `s` is null  
 Since:  
 1.2

Method Detail

* #### add  
public void add([Area](../../../java/awt/geom/Area.html "class in java.awt.geom") rhs)  
Adds the shape of the specified `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)  
     ################     ################     ################  
     ##############         ##############     ################  
     ############             ############     ################  
     ##########                 ##########     ################  
     ########                     ########     ################  
     ######                         ######     ######    ######  
     ####                             ####     ####        ####  
     ##                                 ##     ##            ##  
       
Parameters:  
`rhs` \- the `Area` to be added to the current shape  
Throws:  
`[NullPointerException](../../../java/lang/NullPointerException.html "class in java.lang")` \- if `rhs` is null  
Since:  
1.2  
* #### subtract  
public void subtract([Area](../../../java/awt/geom/Area.html "class in java.awt.geom") rhs)  
Subtracts the shape of the specified `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)  
     ################     ################  
     ##############         ##############     ##  
     ############             ############     ####  
     ##########                 ##########     ######  
     ########                     ########     ########  
     ######                         ######     ######  
     ####                             ####     ####  
     ##                                 ##     ##  
       
Parameters:  
`rhs` \- the `Area` to be subtracted from the current shape  
Throws:  
`[NullPointerException](../../../java/lang/NullPointerException.html "class in java.lang")` \- if `rhs` is null  
Since:  
1.2  
* #### intersect  
public void intersect([Area](../../../java/awt/geom/Area.html "class in java.awt.geom") rhs)  
Sets the shape of this `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)  
     ################     ################     ################  
     ##############         ##############       ############  
     ############             ############         ########  
     ##########                 ##########           ####  
     ########                     ########  
     ######                         ######  
     ####                             ####  
     ##                                 ##  
       
Parameters:  
`rhs` \- the `Area` to be intersected with this`Area`  
Throws:  
`[NullPointerException](../../../java/lang/NullPointerException.html "class in java.lang")` \- if `rhs` is null  
Since:  
1.2  
* #### exclusiveOr  
public void exclusiveOr([Area](../../../java/awt/geom/Area.html "class in java.awt.geom") 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. 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)  
     ################     ################  
     ##############         ##############     ##            ##  
     ############             ############     ####        ####  
     ##########                 ##########     ######    ######  
     ########                     ########     ################  
     ######                         ######     ######    ######  
     ####                             ####     ####        ####  
     ##                                 ##     ##            ##  
       
Parameters:  
`rhs` \- the `Area` to be exclusive ORed with this`Area`.  
Throws:  
`[NullPointerException](../../../java/lang/NullPointerException.html "class in java.lang")` \- if `rhs` is null  
Since:  
1.2  
* #### reset  
public void reset()  
Removes all of the geometry from this `Area` and restores it to an empty area.  
Since:  
1.2  
* #### isEmpty  
public boolean isEmpty()  
Tests whether this `Area` object encloses any area.  
Returns:  
`true` if this `Area` object represents an empty area; `false` otherwise.  
Since:  
1.2  
* #### isPolygonal  
public boolean isPolygonal()  
Tests whether this `Area` consists entirely of straight edged polygonal geometry.  
Returns:  
`true` if the geometry of this`Area` consists entirely of line segments;`false` otherwise.  
Since:  
1.2  
* #### isRectangular  
public boolean isRectangular()  
Tests whether this `Area` is rectangular in shape.  
Returns:  
`true` if the geometry of this`Area` is rectangular in shape; `false` otherwise.  
Since:  
1.2  
* #### isSingular  
public boolean isSingular()  
Tests whether this `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](../../../java/awt/geom/PathIterator.html#SEG%5FMOVETO) segments that appear in the path.  
Returns:  
`true` if the `Area` is comprised of a single basic geometry; `false` otherwise.  
Since:  
1.2  
* #### getBounds2D  
public [Rectangle2D](../../../java/awt/geom/Rectangle2D.html "class in java.awt.geom") getBounds2D()  
Returns a high precision bounding [Rectangle2D](../../../java/awt/geom/Rectangle2D.html "class in java.awt.geom") 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.  
Specified by:  
`[getBounds2D](../../../java/awt/Shape.html#getBounds2D--)` in interface `[Shape](../../../java/awt/Shape.html "interface in java.awt")`  
Returns:  
the bounding `Rectangle2D` for the`Area`.  
Since:  
1.2  
See Also:  
[Shape.getBounds()](../../../java/awt/Shape.html#getBounds--)  
* #### getBounds  
public [Rectangle](../../../java/awt/Rectangle.html "class in java.awt") getBounds()  
Returns a bounding [Rectangle](../../../java/awt/Rectangle.html "class in java.awt") 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.  
Specified by:  
`[getBounds](../../../java/awt/Shape.html#getBounds--)` in interface `[Shape](../../../java/awt/Shape.html "interface in java.awt")`  
Returns:  
the bounding `Rectangle` for the`Area`.  
Since:  
1.2  
See Also:  
[Shape.getBounds2D()](../../../java/awt/Shape.html#getBounds2D--)  
* #### clone  
public [Object](../../../java/lang/Object.html "class in java.lang") clone()  
Returns an exact copy of this `Area` object.  
Overrides:  
`[clone](../../../java/lang/Object.html#clone--)` in class `[Object](../../../java/lang/Object.html "class in java.lang")`  
Returns:  
Created clone object  
Since:  
1.2  
See Also:  
[Cloneable](../../../java/lang/Cloneable.html "interface in java.lang")  
* #### equals  
public boolean equals([Area](../../../java/awt/geom/Area.html "class in java.awt.geom") other)  
Tests whether the geometries of the two `Area` objects are equal. This method will return false if the argument is null.  
Parameters:  
`other` \- the `Area` to be compared to this`Area`  
Returns:  
`true` if the two geometries are equal;`false` otherwise.  
Since:  
1.2  
* #### transform  
public void transform([AffineTransform](../../../java/awt/geom/AffineTransform.html "class in java.awt.geom") t)  
Transforms the geometry of this `Area` using the specified[AffineTransform](../../../java/awt/geom/AffineTransform.html "class in java.awt.geom"). 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](../../../java/lang/NullPointerException.html "class in java.lang")` \- if `t` is null  
Since:  
1.2  
* #### createTransformedArea  
public [Area](../../../java/awt/geom/Area.html "class in java.awt.geom") createTransformedArea([AffineTransform](../../../java/awt/geom/AffineTransform.html "class in java.awt.geom") t)  
Creates a new `Area` object that contains the same geometry as this `Area` transformed by 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.  
Throws:  
`[NullPointerException](../../../java/lang/NullPointerException.html "class in java.lang")` \- if `t` is null  
Since:  
1.2  
* #### contains  
public 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](../../../java/awt/Shape.html#def%5Finsideness).  
Specified by:  
`[contains](../../../java/awt/Shape.html#contains-double-double-)` in interface `[Shape](../../../java/awt/Shape.html "interface in java.awt")`  
Parameters:  
`x` \- the specified X coordinate to be tested  
`y` \- the specified Y coordinate to be tested  
Returns:  
`true` if the specified coordinates are inside the `Shape` boundary; `false` otherwise.  
Since:  
1.2  
* #### contains  
public boolean contains([Point2D](../../../java/awt/geom/Point2D.html "class in java.awt.geom") p)  
Specified by:  
`[contains](../../../java/awt/Shape.html#contains-java.awt.geom.Point2D-)` in interface `[Shape](../../../java/awt/Shape.html "interface in java.awt")`  
Parameters:  
`p` \- the specified `Point2D` to be tested  
Returns:  
`true` if the specified `Point2D` is inside the boundary of the `Shape`;`false` otherwise.  
Since:  
1.2  
* #### contains  
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 rectangular 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](../../../java/awt/geom/Area.html "class in java.awt.geom") class performs more accurate geometric computations than most`Shape` objects and therefore can be used if a more precise answer is required.  
Specified by:  
`[contains](../../../java/awt/Shape.html#contains-double-double-double-double-)` in interface `[Shape](../../../java/awt/Shape.html "interface in java.awt")`  
Parameters:  
`x` \- the X coordinate of the upper-left corner of the specified rectangular area  
`y` \- the Y coordinate 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 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  
See Also:  
[Area](../../../java/awt/geom/Area.html "class in java.awt.geom"), [Shape.intersects(double, double, double, double)](../../../java/awt/Shape.html#intersects-double-double-double-double-)  
* #### contains  
public boolean contains([Rectangle2D](../../../java/awt/geom/Rectangle2D.html "class in java.awt.geom") 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](../../../java/awt/geom/Area.html "class in java.awt.geom") class performs more accurate geometric computations than most`Shape` objects and therefore can be used if a more precise answer is required.  
Specified by:  
`[contains](../../../java/awt/Shape.html#contains-java.awt.geom.Rectangle2D-)` in interface `[Shape](../../../java/awt/Shape.html "interface in java.awt")`  
Parameters:  
`r` \- The specified `Rectangle2D`  
Returns:  
`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  
See Also:  
[Shape.contains(double, double, double, double)](../../../java/awt/Shape.html#contains-double-double-double-double-)  
* #### intersects  
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](../../../java/awt/geom/Area.html "class in java.awt.geom") 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 by:  
`[intersects](../../../java/awt/Shape.html#intersects-double-double-double-double-)` in interface `[Shape](../../../java/awt/Shape.html "interface in java.awt")`  
Parameters:  
`x` \- the X coordinate of the upper-left corner of the specified rectangular area  
`y` \- the Y coordinate 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 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  
See Also:  
[Area](../../../java/awt/geom/Area.html "class in java.awt.geom")  
* #### intersects  
public boolean intersects([Rectangle2D](../../../java/awt/geom/Rectangle2D.html "class in java.awt.geom") 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](../../../java/awt/geom/Area.html "class in java.awt.geom") 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 by:  
`[intersects](../../../java/awt/Shape.html#intersects-java.awt.geom.Rectangle2D-)` in interface `[Shape](../../../java/awt/Shape.html "interface in java.awt")`  
Parameters:  
`r` \- the specified `Rectangle2D`  
Returns:  
`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  
See Also:  
[Shape.intersects(double, double, double, double)](../../../java/awt/Shape.html#intersects-double-double-double-double-)  
* #### getPathIterator  
public [PathIterator](../../../java/awt/geom/PathIterator.html "interface in java.awt.geom") getPathIterator([AffineTransform](../../../java/awt/geom/AffineTransform.html "class in java.awt.geom") at)  
Creates a [PathIterator](../../../java/awt/geom/PathIterator.html "interface in java.awt.geom") for the outline of this`Area` object. This `Area` object is unchanged.  
Specified by:  
`[getPathIterator](../../../java/awt/Shape.html#getPathIterator-java.awt.geom.AffineTransform-)` in interface `[Shape](../../../java/awt/Shape.html "interface in java.awt")`  
Parameters:  
`at` \- 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.  
Since:  
1.2  
* #### getPathIterator  
public [PathIterator](../../../java/awt/geom/PathIterator.html "interface in java.awt.geom") getPathIterator([AffineTransform](../../../java/awt/geom/AffineTransform.html "class in java.awt.geom") at,  
                                    double flatness)  
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](../../../java/awt/Shape.html#getPathIterator-java.awt.geom.AffineTransform-double-)` in interface `[Shape](../../../java/awt/Shape.html "interface in java.awt")`  
Parameters:  
`at` \- 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 end points  
Returns:  
the `PathIterator` object that returns the geometry of the outline of this `Area`, one segment at a time.  
Since:  
1.2

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Area (Java Platform SE 8 ) (original) (raw)

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