acm.graphics
Class GTurtle

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

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

GTurtle()

GTurtle(double x, double y)

Method Summary

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.
void	main(String[] args) Makes it possible for a GTurtle to be run under the control of a GraphicsProgram 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(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.

Inherited Method Summary

Color	getColor() Returns the color used to display this object.
GPoint	getLocation() Returns the location of this object as a GPoint.
GDimension	getSize() Returns the size of the bounding box for this object.
double	getX() Returns the x-coordinate of the object.
double	getX() Returns the x-coordinate of the object.
double	getY() Returns the y-coordinate of the object.
double	getY() Returns the y-coordinate of the object.
boolean	isVisible() Checks to see whether the trace of the turtle is visible.
void	sendBackward() Moves this object one step toward the back in the z dimension.
void	sendForward() Moves this object one step toward the front in the z dimension.
void	sendToBack() Moves this object to the back of the display in the z dimension.
void	sendToFront() Moves this object to the front of the display in the z dimension.
void	setLocation(GPoint pt) Sets the location of this object to the specified point.
void	setVisible(boolean visible) Sets whether the trace of the turtle is visible.

Constructor Detail

public GTurtle()

Creates a new GTurtle object.

Usage:

GTurtle turtle = new GTurtle();

public GTurtle(double x, double y)

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

Usage:

GTurtle turtle = new GTurtle(x, y);

Parameters:

x	The initial x coordinate of the turtle
y	The initial y coordinate of the turtle

Method Detail

public void erasePath()

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

Usage:

turtle.erasePath();

public final void forward()

Moves the turtle forward by its own size.

Usage:

turtle.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.

Usage:

turtle.forward(distance);

Parameter:

distance

The distance to move in the current direction

public GRectangle getBounds()

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

Usage:	bounds = getBounds();
Returns:	A GRectangle representing the bounding box

public double getDirection()

Returns the direction specified by setDirection.

Usage:	double dir = turtle.getDirection();
Returns:	The direction in which the turtle is moving

public double getSpeed()

Returns the current speed of the turtle.

Usage:	double speed = turtle.getSpeed();
Returns:	The current speed of the turtle (0 is slowest, 1 is fastest)

public int getTurtleSize()

Returns the size of the turtle.

Usage:	int size = turtle.getSize();
Returns:	The size of the turtle image in pixels

public final void hideTurtle()

Hides the turtle.

Usage:

turtle.hideTurtle();

public boolean isPenDown()

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

Usage:	if (turtle.isPenDown()) . . .
Returns:	true if the pen is down, false otherwise

public boolean isTurtleVisible()

Returns whether the turtle is visible.

Usage:	if (turtle.isTurtleVisible()) . . .
Returns:	true if the turtle is visible, otherwise false

public final void left(double angle)

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

Usage:

turtle.left(angle);

Parameter:

angle

The angle to turn, measured in degrees

public static void main(String[] args)

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

Usage:

main(args);

Parameter:

args	An array of string arguments

public final void penDown()

Lowers the pen.

Usage:

turtle.penDown();

public final void penUp()

Raises the pen.

Usage:

turtle.penUp();

public final void right(double angle)

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

Usage:

turtle.right(angle);

Parameter:

angle

The angle to turn, measured in degrees

public void setColor(Color color)

Sets the color of the turtle's pen.

Usage:

turtle.setColor(color);

Parameter:

color

The new color for the pen

public void setDirection(double dir)

Sets the direction in which the turtle is moving.

Usage:

turtle.setDirection(dir);

Parameter:

dir	The direction in which the turtle is moving

public void setLocation(double x, double y)

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

Usage:

turtle.setLocation(x, y);

Parameters:

x	The x-coordinate of the new position
y	The y-coordinate of the new position

public void setSize(int size)

Sets the size of the turtle.

Usage:

turtle.setSize(size);

Parameter:

The	size of the turtle image in pixels

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.

Usage:

turtle.setSpeed(speed);

Parameter:

speed

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

public final void showTurtle()

Makes the turtle visible.

Usage:

turtle.showTurtle();