acm.graphics
Class GPolygon

java.lang.Object
  |
  +--acm.graphics.GObject
        |
        +--acm.graphics.GPolygon

public class GPolygon extends GObject

The GPolygon class is a graphical object whose appearance consists of a polygon.

[examples forthcoming]

Constructor Summary

GPolygon()

GPolygon(double x, double y)

Method Summary

void	addEdge(double dx, double dy) Adds an edge to the polygon whose components are given by the displacements dx and dy.
void	addEdgeInPolarCoordinates(double r, double theta) Adds an edge to the polygon specified in polar coordinates.
static double	angle(double x, double y) Returns the angle in degrees from the origin to the point (x, y).
Object	clone() Overrides clone in Object to make sure that the point arrays are copied rather than shared.
boolean	contains(double x, double y) Checks to see whether a point is inside the object.
static double	cosD(double angle) Returns the trigonometric sine of its argument where angle is expressed in degrees.
static double	distance(double x, double y) Computes the distance between the origin and the point (x, y).
static double	distance(double x0, double y0, double x1, double y1) Computes the distance between the points (x0, y0) and (x1, y1).
void	endPolygon() Ends the polygon and makes it available for display.
Rectangle	getBounds() Returns the bounding box of this object, which is defined to be the smallest rectangle that covers everything drawn by the figure.
double	getHeight() Returns the height of this polygon.
Polygon	getPolygon() Returns an AWT Polygon whose point are as close as possible to the ones in this GPolygon.
Dimension	getSize() Returns the size of this polygon.
double	getWidth() Returns the width of this polygon.
void	paint(Graphics g) Implements the paint operation for this graphical object.
void	rotate(double theta) Rotates the polygon around its origin by the angle theta, measured in degrees.
void	scale(double sx, double sy) Scales the polygon by the scale factors sx and sy.
static double	sinD(double angle) Returns the trigonometric sine of its argument where angle is expressed in degrees.
void	startPolygon() Starts a polygon at its origin.
void	startPolygon(double x, double y) Sets the start location of the polygon relative to its origin.
static double	tanD(double angle) Returns the trigonometric sine of its argument where angle is expressed in degrees.
static double	toDegrees(double radians) Converts an angle from radians to degrees.
static double	toRadians(double degrees) Converts an angle from degrees to radians.

Inherited Method Summary

void	addMouseListener(MouseListener listener) Adds a mouse listener to this graphical object. [Inherited from GObject]
void	addMouseMotionListener(MouseMotionListener listener) Adds a mouse motion listener to this graphical object. [Inherited from GObject]
Color	getColor() Returns the color used to display this object. [Inherited from GObject]
Color	getFillColor() Returns the color used to display the filled region of this object. [Inherited from GObject]
Point	getLocation() Returns the nearest Point corresponding to the location of this object. [Inherited from GObject]
double	getX() Returns the x-coordinate of the object. [Inherited from GObject]
double	getY() Returns the y-coordinate of the object. [Inherited from GObject]
boolean	isFilled() Returns whether this object is filled. [Inherited from GObject]
boolean	isVisible() Checks to see whether this object is visible. [Inherited from GObject]
void	moveToBack() Moves this object to the back of the display in stacking order. [Inherited from GObject]
void	moveToFront() Moves this object to the front of the display in stacking order. [Inherited from GObject]
void	removeMouseListener(MouseListener listener) Removes a mouse listener from this graphical object. [Inherited from GObject]
void	removeMouseMotionListener(MouseMotionListener listener) Removes a mouse motion listener from this graphical object. [Inherited from GObject]
void	setColor(Color c) Sets the color used to display this object. [Inherited from GObject]
void	setFillColor(Color c) Sets the color used to display the filled region of this object. [Inherited from GObject]
void	setFilled(boolean fill) Sets whether this object is filled. [Inherited from GObject]
void	setLocation(double x, double y) Sets the location of this object to the point (x, y). [Inherited from GObject]
void	setVisible(boolean visible) Sets whether this object is visible. [Inherited from GObject]
void	translate(double dx, double dy) Moves the object on the screen using the displacements dx and dy. [Inherited from GObject]

Constructor Detail

public GPolygon()

Constructs a new empty polygon at the origin.

Usage:

GPolygon gpoly = new GPolygon();

public GPolygon(double x, double y)

Constructs a new empty polygon at (x, y).

Usage:

GPolygon gpoly = new GPolygon(x, y);

Parameters:

x	The x-coordinate of the origin of the polygon
y	The y-coordinate of the origin of the polygon

Method Detail

public void addEdge(double dx, double dy)

Adds an edge to the polygon whose components are given by the displacements dx and dy.

Usage:

gpoly.addEdge(dx, dy);

Parameters:

dx	The x displacement through which the edge moves
dy	The y displacement through which the edge moves

public void addEdgeInPolarCoordinates(double r, double theta)

Adds an edge to the polygon specified in polar coordinates. The length of the edge is given by r, and the edge extends in direction theta, measured in degrees counterclockwise from the +x axis.

Usage:

gpoly.addEdgeInPolarCoordinates(r, theta);

Parameters:

r	The length of the edge
theta	The angle at which the edge extends measured in degrees

public static double angle(double x, double y)

Returns the angle in degrees from the origin to the point (x, y). This method is easier to use than atan2 because it specifies the displacements in the usual x/y order and because it takes care of the fact that the Java coordinate system is flipped. The point (0, 0) is arbitrarily defined to be at angle 0.

public Object clone()

Overrides clone in Object to make sure that the point arrays are copied rather than shared.

public boolean contains(double x, double y)

Checks to see whether a point is inside the object.

Usage:

if (gpoly.contains(x, y)) . . .

Parameters:

x	The x-coordinate of the point being tested
y	The y-coordinate of the point being tested

Returns:

true if the point (x, y) is inside the object, and false otherwise

public static double cosD(double angle)

Returns the trigonometric sine of its argument where angle is expressed in degrees.

public static double distance(double x, double y)

Computes the distance between the origin and the point (x, y).

public static double distance(double x0, double y0, double x1, double y1)

Computes the distance between the points (x0, y0) and (x1, y1).

public void endPolygon()

Ends the polygon and makes it available for display.

Usage:

gpoly.endPolygon();

public Rectangle getBounds()

Returns the bounding box of this object, which is defined to be the smallest rectangle that covers everything drawn by the figure.

Usage:	Rectangle bounds = gpoly.getBounds();
Returns:	The bounding box for this object

public double getHeight()

Returns the height of this polygon.

Usage:	double height = gpoly.getHeight();
Returns:	The height of this object on the screen

public Polygon getPolygon()

Returns an AWT Polygon whose point are as close as possible to the ones in this GPolygon.

Usage:	Polygon p = gpoly.getPolygon();
Returns:	An AWT polygon corresponding to this object

public Dimension getSize()

Returns the size of this polygon.

Usage:	Dimension size = gpoly.getSize();
Returns:	The size of this object

public double getWidth()

Returns the width of this polygon.

Usage:	double width = gpoly.getWidth();
Returns:	The width of this object

public void paint(Graphics g)

Implements the paint operation for this graphical object. This method is not called directly by clients.

public void rotate(double theta)

Rotates the polygon around its origin by the angle theta, measured in degrees.

Usage:

gpoly.rotate(theta);

Parameter:

theta

The angle of rotation in degrees counterclockwise

public void scale(double sx, double sy)

Scales the polygon by the scale factors sx and sy.

Usage:

gpoly.scale(sx, sy);

Parameters:

sx	The factor used to scale all coordinates in the x direction
sy	The factor used to scale all coordinates in the y direction

public static double sinD(double angle)

Returns the trigonometric sine of its argument where angle is expressed in degrees.

public final void startPolygon()

Starts a polygon at its origin.

Usage:

gpoly.startPolygon();

public void startPolygon(double x, double y)

Sets the start location of the polygon relative to its origin.

Usage:

gpoly.startPolygon(x, y);

Parameters:

x	The x-coordinate of the start of the figure relative to the polygon origin
y	The y-coordinate of the start of the figure relative to the polygon origin

public static double tanD(double angle)

Returns the trigonometric sine of its argument where angle is expressed in degrees.

public static double toDegrees(double radians)

Converts an angle from radians to degrees. This method is defined in the Math class, but was added only in JDK1.2, which is not supported in all browsers.

public static double toRadians(double degrees)

Converts an angle from degrees to radians. This method is defined in the Math class, but was added only in JDK1.2, which is not supported in all browsers.