JavaTM 2 Platform
Standard Edition

java.awt
Class Polygon

java.lang.Object
  |
  +--java.awt.Polygon

public class Polygon
extends Object
implements Shape, Serializable

The Polygon class encapsulates a description of a closed, two-dimensional region within a coordinate space. This region is bounded by an arbitrary number of line segments, each of which is one side of the polygon. Internally, a polygon comprises of a list of (xy) coordinate pairs, where each pair defines a vertex of the polygon, and two successive pairs are the endpoints of a line that is a side of the polygon. The first and final pairs of (xy) points are joined by a line segment that closes the polygon.

Since:
JDK1.0
See Also:
Serialized Form

Field Summary
protected  Rectangle bounds
          Bounds of the polygon.
 int npoints
          The total number of points.
 int[] xpoints
          The array of x coordinates.
 int[] ypoints
          The array of y coordinates.
 
Constructor Summary
Polygon()
          Creates an empty polygon.
Polygon(int[] xpoints, int[] ypoints, int npoints)
          Constructs and initializes a Polygon from the specified parameters.
 
Method Summary
 void addPoint(int x, int y)
          Appends the specified coordinates to this Polygon.
 boolean contains(double x, double y)
          Tests if the specified coordinates are inside the boundary of the Shape.
 boolean contains(double x, double y, double w, double h)
          Tests if the interior of this Polygon entirely contains the specified set of rectangular coordinates.
 boolean contains(int x, int y)
          Determines whether the specified coordinates are contained in this Polygon.
 boolean contains(Point p)
          Determines whether the specified Point is inside this Polygon.
 boolean contains(Point2D p)
          Tests if a specified Point2D is inside the boundary of this Polygon.
 boolean contains(Rectangle2D r)
          Tests if the interior of this Polygon entirely contains the specified Rectangle2D.
 Rectangle getBoundingBox()
          Deprecated. As of JDK version 1.1, replaced by getBounds().
 Rectangle getBounds()
          Gets the bounding box of this Polygon.
 Rectangle2D getBounds2D()
          Returns the high precision bounding box of the Shape.
 PathIterator getPathIterator(AffineTransform at)
          Returns an iterator object that iterates along the boundary of this Polygon and provides access to the geometry of the outline of this Polygon.
 PathIterator getPathIterator(AffineTransform at, double flatness)
          Returns an iterator object that iterates along the boundary of the Shape and provides access to the geometry of the outline of the Shape.
 boolean inside(int x, int y)
          Deprecated. As of JDK version 1.1, replaced by contains(int, int).
 boolean intersects(double x, double y, double w, double h)
          Tests if the interior of this Polygon intersects the interior of a specified set of rectangular coordinates.
 boolean intersects(Rectangle2D r)
          Tests if the interior of this Polygon intersects the interior of a specified Rectangle2D.
 void translate(int deltaX, int deltaY)
          Translates the vertices of the Polygon by deltaX along the x axis and by deltaY along the y axis.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

npoints

public int npoints
The total number of points. This value can be NULL.
See Also:
addPoint(int, int)

xpoints

public int[] xpoints
The array of x coordinates.
See Also:
addPoint(int, int)

ypoints

public int[] ypoints
The array of y coordinates.
See Also:
addPoint(int, int)

bounds

protected Rectangle bounds
Bounds of the polygon. This value can be NULL. Please see the javadoc comments getBounds().
See Also:
getBoundingBox(), getBounds()
Constructor Detail

Polygon

public Polygon()
Creates an empty polygon.

Polygon

public Polygon(int[] xpoints,
               int[] ypoints,
               int npoints)
Constructs and initializes a Polygon from the specified parameters.
Parameters:
xpoints - an array of x coordinates
ypoints - an array of y coordinates
npoints - the total number of points in the Polygon
Throws:
NegativeArraySizeException - if the value of npoints is negative.
Method Detail

translate

public void translate(int deltaX,
                      int deltaY)
Translates the vertices of the Polygon by deltaX along the x axis and by deltaY along the y axis.
Parameters:
deltaX - the amount to translate along the x axis
deltaY - the amount to translate along the y axis
Since:
JDK1.1

addPoint

public void addPoint(int x,
                     int y)
Appends the specified coordinates to this Polygon.

If an operation that calculates the bounding box of this Polygon has already been performed, such as getBounds or contains, then this method updates the bounding box.

Parameters:
x, y - the specified coordinates
See Also:
getBounds(), contains(java.awt.Point)

getBounds

public Rectangle getBounds()
Gets the bounding box of this Polygon. The bounding box is the smallest Rectangle whose sides are parallel to the x and y axes of the coordinate space, and can completely contain the Polygon.
Specified by:
getBounds in interface Shape
Returns:
a Rectangle that defines the bounds of this Polygon.
Since:
JDK1.1

getBoundingBox

public Rectangle getBoundingBox()
Deprecated. As of JDK version 1.1, replaced by getBounds().


contains

public boolean contains(Point p)
Determines whether the specified Point is inside this Polygon. Uses an even-odd insideness rule (also known as an alternating rule).
Parameters:
p - the specified Point to be tested
Returns:
true if the Polygon contains the Point; false otherwise.

contains

public boolean contains(int x,
                        int y)
Determines whether the specified coordinates are contained in this Polygon.

(The contains method is based on code by Hanpeter van Vliet [hvvliet@inter.nl.net].)

Parameters:
x, y - the specified coordinates to be tested
Returns:
true if this Polygon contains the specified coordinates, (xy); false otherwise.
Since:
JDK1.1

inside

public boolean inside(int x,
                      int y)
Deprecated. As of JDK version 1.1, replaced by contains(int, int).


getBounds2D

public Rectangle2D getBounds2D()
Returns the high precision bounding box of the Shape.
Specified by:
getBounds2D in interface Shape
Returns:
a Rectangle2D that precisely bounds the Shape.

contains

public boolean contains(double x,
                        double y)
Tests if the specified coordinates are inside the boundary of the Shape.
Specified by:
contains in interface Shape
Parameters:
x, y - the specified coordinates
Returns:
true if the Shape contains the specified coordinates; false otherwise.

contains

public boolean contains(Point2D p)
Tests if a specified Point2D is inside the boundary of this Polygon.
Specified by:
contains in interface Shape
Parameters:
p - a specified Point2D
Returns:
true if this Polygon contains the specified Point2D; false otherwise.

intersects

public boolean intersects(double x,
                          double y,
                          double w,
                          double h)
Tests if the interior of this Polygon intersects the interior of a specified set of rectangular coordinates.
Specified by:
intersects in interface Shape
Parameters:
x, y - the coordinates of the specified rectangular shape's top-left corner
w - the width of the specified rectangular shape
h - the height of the specified rectangular shape
Returns:
true if the interior of this Polygon and the interior of the specified set of rectangular coordinates intersect each other; false otherwise.

intersects

public boolean intersects(Rectangle2D r)
Tests if the interior of this Polygon intersects the interior of a specified Rectangle2D.
Specified by:
intersects in interface Shape
Parameters:
r - a specified Rectangle2D
Returns:
true if this Polygon and the interior of the specified Rectangle2D intersect each other; false otherwise.

contains

public boolean contains(double x,
                        double y,
                        double w,
                        double h)
Tests if the interior of this Polygon entirely contains the specified set of rectangular coordinates.
Specified by:
contains in interface Shape
Parameters:
x, y - the coordinate of the top-left corner of the specified set of rectangular coordinates
w - the width of the set of rectangular coordinates
h - the height of the set of rectangular coordinates
Returns:
true if this Polygon entirely contains the specified set of rectangular coordinates; false otherwise.

contains

public boolean contains(Rectangle2D r)
Tests if the interior of this Polygon entirely contains the specified Rectangle2D.
Specified by:
contains in interface Shape
Parameters:
r - the specified Rectangle2D
Returns:
true if this Polygon entirely contains the specified Rectangle2D; false otherwise.

getPathIterator

public PathIterator getPathIterator(AffineTransform at)
Returns an iterator object that iterates along the boundary of this Polygon and provides access to the geometry of the outline of this Polygon. An optional AffineTransform can be specified so that the coordinates returned in the iteration are transformed accordingly.
Specified by:
getPathIterator in interface Shape
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:
a PathIterator object that provides access to the geometry of this Polygon.

getPathIterator

public PathIterator getPathIterator(AffineTransform at,
                                    double flatness)
Returns an iterator object that iterates along the boundary of the Shape and provides access to the geometry of the outline of the Shape. Only SEG_MOVETO, SEG_LINETO, and SEG_CLOSE point types are returned by the iterator. Since polygons are already flat, the flatness parameter is ignored. An optional AffineTransform can be specified in which case the coordinates returned in the iteration are transformed accordingly.
Specified by:
getPathIterator in interface Shape
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 endpoints. Since polygons are already flat the flatness parameter is ignored.
Returns:
a PathIterator object that provides access to the Shape object's geometry.

JavaTM 2 Platform
Standard Edition

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