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Chapter 19 java.awt Reference |
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Polygon
Name
Polygon
![[Graphic: Figure from the text]](./figs/polygon.gif)
Description
The Polygon class encapsulates a collection of points used to create a series of line segments.
Class Definition
public class java.awt.Polygon
extends java.lang.Object
implements java.awt.Shape, java.io.Serializable {
// Variables
protected Rectangle bounds; 
public int npoints;
public int xpoints[];
public int ypoints[];
// Constructors
public Polygon();
public Polygon (int xpoints[], int ypoints, int npoints);
// Instance Methods
public void addPoint (int x, int y);
public boolean contains (int x, int y);
public boolean contains (Point p);
public Rectangle getBoundingBox(); 
public Rectangle getBounds();
public boolean inside (int x,int y);
public void translate (int deltaX, int deltaY);
}
Variables
bounds
protected Rectangle bounds
The rectangle that describes the boundaries of the Polygon.
npoints
public int npoints
The number of elements to use in the xpoints and ypoints arrays.
xpoints
public int xpoints[]
The array of x coordinates for each point.
ypoints
public int ypoints[]
The array of y coordinates for each point.
Constructors
Polygon
public Polygon()
- Description
-
Constructs an empty Polygon object with no points.
public Polygon (int xPoints[], int yPoints[], int numPoints)
- Parameters
-
- xPoints[]
-
The initial array of x coordinates for each point.
- yPoints[]
-
The initial array of y coordinates for each point.
- numPoints
-
The number of elements in both xPoints and yPoints arrays to use.
- xPoints[]
- Throws
-
- ArrayIndexOutOfBoundsException
-
If numPoints > xPoints.length or numPoints > yPoints.length.
- ArrayIndexOutOfBoundsException
- Description
-
Constructs a Polygon object with the set of points provided.
Instance Methods
addPoint
public void addPoint (int x, int y)
- Parameters
-
- x
-
The x coordinate of the point to be added.
- y
-
The y coordinate of the point to be added.
- x
- Description
-
Adds the point (x, y) to the end of the list of points for the Polygon.
contains
public boolean contains (int x, int y)
- Parameters
-
- x
-
The x coordinate to test.
- y
-
The y coordinate to test.
- x
- Returns
-
true if the Polygon contains the point; false otherwise.
public boolean contains (Point p)
- Parameters
-
- p
-
The point to be tested.
- p
- Returns
-
true if the Polygon contains the point; false otherwise.
getBoundingBox
public Rectangle getBoundingBox()
- Returns
-
Bounding Rectangle of the points within the Polygon.
- Description
-
Returns the smallest Rectangle that contains all the points within the Polygon. Replaced by getBounds().
getBounds
public Rectangle getBounds()
- Implements
-
Shape.getBounds()
- Returns
-
Bounding Rectangle of the points within the Polygon.
- Description
-
Returns the smallest Rectangle that contains all the points within the Polygon.
inside
public boolean inside (int x,int y)
- Parameters
-
- x
-
The x coordinate of the point to be checked.
- y
-
The y coordinate of the point to be checked.
- x
- Returns
-
true if (x, y) within Polygon, false otherwise.
- Description
-
Checks to see if the (x, y) point is within an area that would be filled if the Polygon was drawn with Graphics.fillPolygon(). Replaced by contains(int, int).
translate
public void translate (int deltaX, int deltaY)
- Parameters
-
- deltaX
-
Amount to move horizontally.
- deltaY
-
Amount to move vertically.
- deltaX
- Description
-
Moves the Polygon to the location (x+deltaX, y+deltaY).
See Also
Graphics, Object, Rectangle
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