slogo.turtle

Class JTurtle

java.lang.Object

slogo.turtle.JTurtle

public class JTurtle
extends java.lang.Object

This class is a simple MoboLogo/Slogo turtle model for illustrating rudimentary MVC for turtles and simple Graphics2D concepts

Field Summary

Fields

Modifier and Type	Field and Description
private java.awt.geom.Point2D	addedPoint
(package private) static int	HEIGHT
(package private) double	myHeading
(package private) java.awt.geom.Point2D	myLinePoint
private java.util.List<TurtleListener>	myListeners
(package private) java.awt.geom.Point2D	myNextPoint
(package private) java.awt.geom.Point2D	myPoint
(package private) Renderer	myRenderer
boolean	pen
(package private) static int	START_X
(package private) static int	START_Y
(package private) static java.util.ArrayList<java.awt.geom.Point2D>	trail
boolean	visible
(package private) static int	WIDTH

Constructor Summary

Constructors

Modifier	Constructor and Description
	JTurtle() Create a turtle using the default (triangle) image.
	JTurtle(java.awt.Image img) Creates a turtle using the given image
private	JTurtle(Renderer renderer)

Method Summary

Modifier and Type	Method and Description
void	addTurtleListener(TurtleListener listener) Add a listener.
void	clearLine() Clears all points within the trail so that the line can be erased.
void	draw(java.awt.Graphics g) Draw the turtle, pass in a Graphics2D object.
void	drawLine(java.awt.Graphics g)
void	drawOldLine(java.util.ArrayList<java.awt.geom.Point2D> al, java.awt.Graphics g)
java.awt.Rectangle	getBounds(java.awt.Rectangle r) Mirrors the functionality of JComponent/Component.
double	getHeading() Returns the naive view of heading, 0 degrees = north
java.lang.String	getPen()
java.awt.geom.Point2D	getPoint() Returns the turtle's point (should be centroid)
void	move(int steps) Moves the turtle forward.
void	notifyListeners() Ask all registered listeners to process this turtle
void	reset() Reposition turtle at the origin, facing north.
void	setHeading(double radians) Set heading in radians, notify listeners.
void	setHeading(int degrees) Set heading in degrees, notify listeners.
boolean	setPenDown()
boolean	setPenDownHome()
boolean	setPenUp()
void	setPoint(java.awt.geom.Point2D p) Sets the turtles point, notifies listeners.
protected double	trueHeading() Return the real/true heading of the turtle.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

myHeading

double myHeading

myPoint

java.awt.geom.Point2D myPoint

myNextPoint

java.awt.geom.Point2D myNextPoint

myLinePoint

java.awt.geom.Point2D myLinePoint

myRenderer

Renderer myRenderer

pen

public boolean pen

visible

public boolean visible

trail

static java.util.ArrayList<java.awt.geom.Point2D> trail

addedPoint

private java.awt.geom.Point2D addedPoint

START_X

static final int START_X

See Also:

Constant Field Values

START_Y

static final int START_Y

See Also:

Constant Field Values

WIDTH

static final int WIDTH

See Also:

Constant Field Values

HEIGHT

static final int HEIGHT

See Also:

Constant Field Values

myListeners

private java.util.List<TurtleListener> myListeners

Constructor Detail

JTurtle

public JTurtle()

Create a turtle using the default (triangle) image.

JTurtle

public JTurtle(java.awt.Image img)

Creates a turtle using the given image

Parameters:

img - the image to use for the turtle

JTurtle

private JTurtle(Renderer renderer)

Method Detail

getBounds

public java.awt.Rectangle getBounds(java.awt.Rectangle r)

Mirrors the functionality of JComponent/Component. The current turtle isn't a Component, but it sort of acts like one (it's drawable).

See Also:

Component.getBounds()

reset

public void reset()

Reposition turtle at the origin, facing north.

draw

public void draw(java.awt.Graphics g)

Draw the turtle, pass in a Graphics2D object.

Parameters:

g - is the graphics context in which Turtle is drawn

drawOldLine

public void drawOldLine(java.util.ArrayList<java.awt.geom.Point2D> al,
                        java.awt.Graphics g)

trueHeading

protected double trueHeading()

Return the real/true heading of the turtle. A Turtle's "heading" is what naive users would expect, i.e., 0 degrees == north, 90 degrees = east, -90 degrees = west. The trueheading translates to what Graphics/geometry expects

Returns:

the true heading in radians

move

public void move(int steps)

Moves the turtle forward.

Parameters:

steps - is the number of steps moved

drawLine

public void drawLine(java.awt.Graphics g)

setHeading

public void setHeading(int degrees)

Set heading in degrees, notify listeners.

Parameters:

degrees - will be Turtle's new heading

setHeading

public void setHeading(double radians)

Set heading in radians, notify listeners.

Parameters:

radians - Turtle's new heading

getHeading

public double getHeading()

Returns the naive view of heading, 0 degrees = north

Returns:

the heading

getPoint

public java.awt.geom.Point2D getPoint()

Returns the turtle's point (should be centroid)

Returns:

the center point

notifyListeners

public void notifyListeners()

Ask all registered listeners to process this turtle

addTurtleListener

public void addTurtleListener(TurtleListener listener)

Add a listener.

Parameters:

listener - is the listener added

setPoint

public void setPoint(java.awt.geom.Point2D p)

Sets the turtles point, notifies listeners.

Parameters:

p - is the new center point

setPenUp

public boolean setPenUp()

setPenDown

public boolean setPenDown()

setPenDownHome

public boolean setPenDownHome()

getPen

public java.lang.String getPen()

clearLine

public void clearLine()

Clears all points within the trail so that the line can be erased.