acm.graphics

Class GTurtle

java.lang.Object

acm.graphics.GObject

acm.graphics.GTurtle

All Implemented Interfaces:

java.lang.Cloneable

public class GTurtle
extends GObject

The GTurtle class simulates a turtle moving on a canvas. This class is similar to the GPen class, but keeps track of both a position and a direction.

Constructor Summary

Constructors

Constructor and Description
GTurtle() Creates a new GTurtle object.
GTurtle(double x, double y) Creates a new GPen positioned at the point (x, y).

Method Summary

Methods

Modifier and Type	Method and Description
boolean	contains(double x, double y) Contains is defined to be false for the GPen object to avoid having the trace intercept mouse clicks.
void	erasePath() Erases the entire path drawn by the turtle but does not change its position.
void	forward() Moves the turtle forward by its own size.
void	forward(double distance) Moves the turtle forward in its current direction by the specified distance.
GRectangle	getBounds() Returns the bounding box for the entire figure traced by the turtle.
double	getDirection() Returns the direction specified by setDirection.
double	getSpeed() Returns the current speed of the turtle.
int	getTurtleSize() Returns the size of the turtle.
void	hideTurtle() Hides the turtle.
boolean	isPenDown() Returns whether the pen is down, as described in setPenDown.
boolean	isTurtleVisible() Returns whether the turtle is visible.
void	left(double angle) Changes the direction of the turtle so that it moves the specified number of degrees to the left.
static void	main(java.lang.String[] args) Makes it possible for a GTurtle to be run under the control of a GraphicsProgram object.
void	move(double dx, double dy) Moves the turtle by the specified displacements.
void	paint(java.awt.Graphics g) Implements the paint operation for this graphical object.
void	penDown() Lowers the pen.
void	penUp() Raises the pen.
void	right(double angle) Changes the direction of the turtle so that it moves the specified number of degrees to the right.
void	setColor(java.awt.Color color) Sets the color of the turtle's pen.
void	setDirection(double dir) Sets the direction in which the turtle is moving.
void	setLocation(double x, double y) Moves the turtle to the point (x, y) without drawing a line.
void	setSize(int size) Sets the size of the turtle.
void	setSpeed(double speed) Sets the speed of the turtle, which must be a number between 0 (slowest) and 1 (fastest).
void	showTurtle() Makes the turtle visible.

Methods inherited from class acm.graphics.GObject

addActionListener, addMouseListener, addMouseMotionListener, contains, fireActionEvent, fireActionEvent, getColor, getHeight, getLocation, getParent, getSize, getWidth, getX, getY, isVisible, movePolar, pause, removeActionListener, removeMouseListener, removeMouseMotionListener, sendBackward, sendForward, sendToBack, sendToFront, setLocation, setParent, setVisible, toString

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

GTurtle

public GTurtle()

Creates a new GTurtle object.

GTurtle

public GTurtle(double x,
       double y)

Creates a new GPen positioned at the point (x, y).

Parameters:

x - The initial x coordinate of the turtle

y - The initial y coordinate of the turtle

Method Detail

erasePath

public void erasePath()

Erases the entire path drawn by the turtle but does not change its position.

setLocation

public void setLocation(double x,
               double y)

Moves the turtle to the point (x, y) without drawing a line.

Overrides:

setLocation in class GObject

Parameters:

x - The x-coordinate of the new position

y - The y-coordinate of the new position

move

public void move(double dx,
        double dy)

Moves the turtle by the specified displacements. The turtle draws a line if its pen is down, but otherwise simply moves. This definition is included because it exists in the GObject superclass but will usually be avoided in favor of forward.

Overrides:

move in class GObject

Parameters:

dx - The distance to move the object in the x direction (positive is rightward)

dy - The distance to move the object in the y direction (positive is downward)

forward

public void forward(double distance)

Moves the turtle forward in its current direction by the specified distance. The turtle draws a line if its pen is down, but otherwise simply moves.

Parameters:

distance - The distance to move in the current direction

forward

public final void forward()

Moves the turtle forward by its own size.

setDirection

public void setDirection(double dir)

Sets the direction in which the turtle is moving.

Parameters:

dir - The direction in which the turtle is moving

getDirection

public double getDirection()

Returns the direction specified by setDirection.

Returns:

The direction in which the turtle is moving

left

public final void left(double angle)

Changes the direction of the turtle so that it moves the specified number of degrees to the left.

Parameters:

angle - The angle to turn, measured in degrees

right

public final void right(double angle)

Changes the direction of the turtle so that it moves the specified number of degrees to the right.

Parameters:

angle - The angle to turn, measured in degrees

isPenDown

public boolean isPenDown()

Returns whether the pen is down, as described in setPenDown.

Returns:

true if the pen is down, false otherwise

penDown

public final void penDown()

Lowers the pen.

penUp

public final void penUp()

Raises the pen.

setColor

public void setColor(java.awt.Color color)

Sets the color of the turtle's pen.

Overrides:

setColor in class GObject

Parameters:

color - The new color for the pen

isTurtleVisible

public boolean isTurtleVisible()

Returns whether the turtle is visible.

Returns:

true if the turtle is visible, otherwise false

showTurtle

public final void showTurtle()

Makes the turtle visible.

hideTurtle

public final void hideTurtle()

Hides the turtle.

setSpeed

public void setSpeed(double speed)

Sets the speed of the turtle, which must be a number between 0 (slowest) and 1 (fastest). Setting speed to a value less than one makes the turtle move slowly, thereby making it easy to see exactly how a figure is being drawn.

Parameters:

speed - The speed of the turtle (0 is slowest, 1 is fastest)

getSpeed

public double getSpeed()

Returns the current speed of the turtle.

Returns:

The current speed of the turtle (0 is slowest, 1 is fastest)

setSize

public void setSize(int size)

Sets the size of the turtle.

Parameters:

The - size of the turtle image in pixels

getTurtleSize

public int getTurtleSize()

Returns the size of the turtle.

Returns:

The size of the turtle image in pixels

paint

public void paint(java.awt.Graphics g)

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

Specified by:

paint in class GObject

Parameters:

g - The graphics context into which the painting is done

getBounds

public GRectangle getBounds()

Returns the bounding box for the entire figure traced by the turtle.

Specified by:

getBounds in class GObject

Returns:

A GRectangle representing the bounding box

contains

public boolean contains(double x,
               double y)

Contains is defined to be false for the GPen object to avoid having the trace intercept mouse clicks.

Overrides:

contains in class GObject

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

main

public static void main(java.lang.String[] args)

Makes it possible for a GTurtle to be run under the control of a GraphicsProgram object.

Parameters:

args - An array of string arguments