Class java.awt.Polygon - JDK 5 Documentation v1.1.8, Java 2 SDK 英文文档

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Class java.awt.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 (x, y) 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 (x, y) points are joined by a line segment that closes the polygon.

bounds
npoints: The total number of points.
xpoints: The array of x coordinates.
ypoints: The array of y coordinates.

Polygon(): Creates an empty polygon.
Polygon(int[], int[], int): Constructs and initializes a polygon from the specified parameters.

addPoint(int, int): Appends a point to this polygon.
contains(int, int): Determines whether the specified point is contained by this polygon.
contains(Point): Determines whether the specified point is inside the Polygon.
getBoundingBox(): Deprecated.
getBounds(): Gets the bounding box of this polygon.
inside(int, int): Deprecated.
translate(int, int): Translates the vertices by deltaX along the x axis and by deltaY along the y axis.

npoints

 public int npoints

The total number of points.

xpoints

 public int xpoints[]

The array of x coordinates.

ypoints

 public int ypoints[]

The array of y coordinates.

bounds

 protected Rectangle bounds

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.

translate

 public void translate(int deltaX,
                       int deltaY)

Translates the vertices 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

addPoint

 public void addPoint(int x,
                      int y)

Appends a point 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 - the x coordinate of the point.; y - the y coordinate of the point.
See Also:: getBounds, contains

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 that can completely contain the polygon.

Returns:: a rectangle that defines the bounds of this polygon.

getBoundingBox

 public Rectangle getBoundingBox()

Note: getBoundingBox() is deprecated. As of JDK version 1.1, replaced by getBounds().

contains

 public boolean contains(Point p)

Determines whether the specified point is inside the Polygon. Uses an even-odd insideness rule (also known as an alternating rule).

Parameters:: p - the point to be tested

contains

 public boolean contains(int x,
                         int y)

Determines whether the specified point is contained by this polygon.

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

Parameters:: x - the x coordinate of the point to be tested.; y - the y coordinate of the point to be tested.
Returns:: true if the point (x, y) is contained by this polygon; false otherwise.

inside

 public boolean inside(int x,
                       int y)

Note: inside() is deprecated. As of JDK version 1.1, replaced by contains(int, int).

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