Turtle (Turtle Logo 1.0.1 API)

java.lang.Object
- org.gannacademy.cdf.turtlelogo.Turtle

Direct Known Subclasses:: AnimatedTurtle

public class Turtle
extends Object

A turtles lives in a Terrarium. We imagine that turtles all hold a pen in their mouth. As they walk around the terrarium, they leave a trail (a series of Track segments) behind them. The turtles can avoid leaving a track if they pick up their pen.

Turtle leaving a trail

Turtles understand a limited number of instructions:


	move( steps) (a.k.a forward or fd and back or bk) — the turtle will step forward, in the direction that it is currently facing, some number of steps (i.e. pixels).
	turn(degrees) (a.k.a. left or lt and right or rt) — the turtle will turn from its current heading some number of degrees.
	moveTo(x, y) (a.k.a. to) — the turtle will move from its current location to the coordinates given, without changing its heading.
	teleport(x, y) (a.k.a. tp) — the turtle will teleport (like in Star Trek) from its current location to the new coordinates, without changing its heading and without allowing the pen to drag between locations.
	penColor(color) (a.k.a. pc) — the turtle will change the color of its pen (initially the pen is black)
	penWidth(width) (a.k.a. pw) — the turtle will change the width of its pen stroke (measured in pixels)
	hide() (a.k.a. ht) — the turtle will hide itself (but remain at its current location and heading)
	show() (a.k.a. st) — the turtle, if hidden, will show itself again

Nested Class Summary

Nested Classes
Modifier and Type Class and Description

static class Turtle.UnderTheShell
The parts of the turtle that are "under the shell" are not meant to be used by students.

Nested Classes
Modifier and Type	Class and Description
`static class`	`Turtle.UnderTheShell` The parts of the turtle that are "under the shell" are not meant to be used by students.

Field Summary

Fields
Modifier and Type	Field and Description
`static double`	`DEFAULT_HEADING_IN_DEGREES` `EAST`
`static boolean`	`DEFAULT_HIDDEN` `false`
`static Color`	`DEFAULT_PEN_COLOR` `Color.BLACK`
`static boolean`	`DEFAULT_PEN_DOWN` `true`
`static float`	`DEFAULT_PEN_WIDTH` 1.0 pixels
`static double`	`EAST` 0°
`static double`	`NORTH` 270°
`static double`	`SOUTH` 90°
`protected static Turtle.UnderTheShell`	`UNDER_THE_SHELL`
`static double`	`WEST` 180°

Constructor Summary

Constructors
Constructor and Description

Turtle()
Construct a turtle in the default terrarium

Turtle(Terrarium terrarium)
Construct a turtle in a custom terrarium

Constructors
Constructor and Description
`Turtle()` Construct a turtle in the default terrarium
`Turtle(Terrarium terrarium)` Construct a turtle in a custom terrarium

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`void`	`back(double steps)` Alias for `move(double)`
`void`	`bk(double steps)` Alias for `back(double)`
`void`	`draw(Graphics2D context, Terrarium.UnderTheSurface key)` Draw the turtle
`protected void`	`drawIcon(double x, double y, double headingInRadians, Graphics2D context)`
`void`	`fd(double steps)` Alias for `forward(double)`
`void`	`forward(double steps)` Alias for `move(double)`
`double`	`getHeadingInDegrees()`
`double`	`getHeadingInRadians()`
`Color`	`getPenColor()`
`protected BasicStroke`	`getPenStroke()`
`double`	`getPenWidth()`
`Terrarium`	`getTerrarium()`
`double`	`getX()`
`double`	`getY()`
`void`	`hd(double heading)` Alias for `head(double)`
`void`	`head(double heading)` Turn the turtle to a particular heading
`void`	`hide()` Hide the turtle
`void`	`home()` Reset the turtle to its home position
`void`	`ht()` Alias for `hide()`
`boolean`	`isHidden()`
`boolean`	`isPenDown()`
`void`	`left(double angle)` Alias for `turn(double)`
`void`	`lt(double angle)` Alias for `left(double)`
`void`	`move(double steps)` Move the turtle in the direction of its current heading
`void`	`moveTo(double x, double y)` Move the turtle to a particular location
`void`	`pc(Color color)` Alias for `penColor(Color)`
`void`	`pd()` Alias for `penDown()`
`void`	`penColor(Color color)` Set the color of the turtle's pen
`void`	`penDown()` Lower the turtle's pen, causing it to leave a trail
`void`	`penUp()` Lift the turtle's pen up, causing it not to leave a track
`void`	`penWidth(double width)` Set the width of the turtle's pen
`void`	`pu()` Alis for `penUp()`
`void`	`pw(double width)` Alias for `penWidth(double)`
`void`	`right(double angle)` Alias for `turn(double)`
`void`	`rt(double angle)` Alias for `right(double)`
`void`	`setTerrarium(Terrarium terrarium)` Move the turtle to another terrarium
`void`	`show()` Show the turtle (if it was hidden)
`void`	`st()` Alias for `show()`
`void`	`teleport(double x, double y)` Move the turtle instantaneously to a particular location
`void`	`to(double x, double y)` Alias for `moveTo(double, double)`
`void`	`tp(double x, double y)` Alias for `teleport(double, double)`
`void`	`turn(double angle)` Turn the turtle from its current heading

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - UNDER_THE_SHELL
```
protected static final Turtle.UnderTheShell UNDER_THE_SHELL
```
  - NORTH
```
public static final double NORTH
```
    270°
    
    See Also:
    
    Constant Field Values
  - SOUTH
```
public static final double SOUTH
```
    90°
    
    See Also:
    
    Constant Field Values
  - EAST
```
public static final double EAST
```
    0°
    
    See Also:
    
    Constant Field Values
  - WEST
```
public static final double WEST
```
    180°
    
    See Also:
    
    Constant Field Values
  - DEFAULT_HEADING_IN_DEGREES
```
public static final double DEFAULT_HEADING_IN_DEGREES
```
    EAST
    
    See Also:
    
    Constant Field Values
  - DEFAULT_PEN_COLOR
```
public static final Color DEFAULT_PEN_COLOR
```
    Color.BLACK
  - DEFAULT_PEN_WIDTH
```
public static final float DEFAULT_PEN_WIDTH
```
    1.0 pixels
    
    See Also:
    
    Constant Field Values
  - DEFAULT_PEN_DOWN
```
public static final boolean DEFAULT_PEN_DOWN
```
    true
    
    See Also:
    
    Constant Field Values
  - DEFAULT_HIDDEN
```
public static final boolean DEFAULT_HIDDEN
```
    false
    
    See Also:
    
    Constant Field Values
- Constructor Detail
  - Turtle
```
public Turtle()
```
    Construct a turtle in the default terrarium
  - Turtle
```
public Turtle(Terrarium terrarium)
```
    Construct a turtle in a custom terrarium
    
    Parameters:
    
    terrarium - to house the turtle
- Method Detail
  - getX
```
public double getX()
```
    Returns:
    
    X-coordinate of turtle
  - getY
```
public double getY()
```
    Returns:
    
    Y-coordinate of turtle
  - getHeadingInDegrees
```
public double getHeadingInDegrees()
```
    Returns:
    
    Current turtle heading in degrees
  - getHeadingInRadians
```
public double getHeadingInRadians()
```
    Returns:
    
    Current turtle heading in radians
  - getPenColor
```
public Color getPenColor()
```
    Returns:
    
    Current pen color
  - getPenWidth
```
public double getPenWidth()
```
    Returns:
    
    Current pen width
  - getPenStroke
```
protected BasicStroke getPenStroke()
```
  - isPenDown
```
public boolean isPenDown()
```
    Returns:
    
    true if the pen is down, false otherwise
  - isHidden
```
public boolean isHidden()
```
    Returns:
    
    true if the turtle is hidden, false otherwise
  - getTerrarium
```
public Terrarium getTerrarium()
```
    Returns:
    
    Terrarium currently housing the turtle
  - setTerrarium
```
public void setTerrarium(Terrarium terrarium)
```
    Move the turtle to another terrarium
    
    Parameters:
    
    terrarium - to house the turtle
  - bk
```
public void bk(double steps)
```
    Alias for back(double)
    
    Parameters:
    
    steps - in pixels
  - back
```
public void back(double steps)
```
    Alias for move(double)
    
    Parameters:
    
    steps - in pixels
  - fd
```
public void fd(double steps)
```
    Alias for forward(double)
    
    Parameters:
    
    steps - in pixels
  - forward
```
public void forward(double steps)
```
    Alias for move(double)
    
    Parameters:
    
    steps - in pixels
  - move
```
public void move(double steps)
```
    Move the turtle in the direction of its current heading
    
    A positive value for steps is interpreted as forward movement and a negative value as backward movement
    
    Parameters:
    
    steps - in pixels
  - to
```
public void to(double x,
               double y)
```
    Alias for moveTo(double, double)
    
    Parameters:
    
    x - coordinate
    
    y - coordinate
  - moveTo
```
public void moveTo(double x,
                   double y)
```
    Move the turtle to a particular location
    
    The turtle moves directly to the window coordinates (x, y). Note that the origin of the wind ow is in the top, left corner and that, while the X-axis increases from left to right, the Y-axis increases from to to bottom.
    
    If the turtle's pen is currently down, the move will create a track from the old location to the new location.
    
    Parameters:
    
    x - coordinate
    
    y - coordinate
  - tp
```
public void tp(double x,
               double y)
```
    Alias for teleport(double, double)
    
    Parameters:
    
    x - coordinate
    
    y - coordinate
  - teleport
```
public void teleport(double x,
                     double y)
```
    Move the turtle instantaneously to a particular location
    
    The turtle moves directly to the window coordinates (x, y). Note that the origin of the wind ow is in the top, left corner and that, while the X-axis increases from left to right, the Y-axis increases from to to bottom.
    
    No track is left by a teleportation.
    
    Parameters:
    
    x - coordinate
    
    y - coordinate
  - home
```
public void home()
```
    Reset the turtle to its home position
    
    The turtle's home position is at the center of the window, heading EAST
  - rt
```
public void rt(double angle)
```
    Alias for right(double)
    
    Parameters:
    
    angle - in degrees
  - right
```
public void right(double angle)
```
    Alias for turn(double)
    
    Parameters:
    
    angle - in degrees
  - lt
```
public void lt(double angle)
```
    Alias for left(double)
    
    Parameters:
    
    angle - in degrees
  - left
```
public void left(double angle)
```
    Alias for turn(double)
    
    Parameters:
    
    angle - in degrees
  - turn
```
public void turn(double angle)
```
    Turn the turtle from its current heading
    
    A positive angle is interpreted as a right turn and a negative angle is a left turn. This is mildly surprising if you know about the unit circle, but is because the Y-axis of the window increases from top to bottom, which results in a mirrored unit circle around the X-axis, with 90° at the SOUTH and270° at the NORTH
    
    Parameters:
    
    angle - in degrees
  - hd
```
public void hd(double heading)
```
    Alias for head(double)
    
    Parameters:
    
    heading - in degrees
  - head
```
public void head(double heading)
```
    Turn the turtle to a particular heading
    
    Note that, because the Y-axis of the window increases from top to bottom, the usual angles of the unit circle have been mirrored around the X-axis, with 90° at the SOUTH and 270%deg; at the NORTH. Convenience constants have been provided for the cardinal directions.
    
    Parameters:
    
    heading - [0..360) in degrees
  - pu
```
public void pu()
```
    Alis for penUp()
  - penUp
```
public void penUp()
```
    Lift the turtle's pen up, causing it not to leave a track
  - pd
```
public void pd()
```
    Alias for penDown()
  - penDown
```
public void penDown()
```
    Lower the turtle's pen, causing it to leave a trail
  - pc
```
public void pc(Color color)
```
    Alias for penColor(Color)
    
    Parameters:
    
    color - to use
  - penColor
```
public void penColor(Color color)
```
    Set the color of the turtle's pen
    
    Color values are given as Color values. Color has a number of helpful constants like Color.GREEN or Color.GREEN. Custom colors can also be constructed. Refer to the java.awt.Color API documentation more details (including how to create transparent colors!)
    
    Parameters:
    
    color - to use
  - pw
```
public void pw(double width)
```
    Alias for penWidth(double)
    
    Parameters:
    
    width - in pixels
  - penWidth
```
public void penWidth(double width)
```
    Set the width of the turtle's pen
    
    Parameters:
    
    width - in pixels
  - ht
```
public void ht()
```
    Alias for hide()
  - hide
```
public void hide()
```
    Hide the turtle
    
    Hiding the turtle causes it to become invisible — it can still be moved and create tracks, but the turtle itself is not visible
  - st
```
public void st()
```
    Alias for show()
  - show
```
public void show()
```
    Show the turtle (if it was hidden)
  - draw
```
public void draw(Graphics2D context,
                 Terrarium.UnderTheSurface key)
```
    Draw the turtle
    
    May only be called by Terrarium and its subclasses, enforced by Terrarium.UnderTheSurface
    
    Parameters:
    
    context - for drawing commands
    
    key - to authenticate "Terrarium-iality"
  - drawIcon
```
protected void drawIcon(double x,
                        double y,
                        double headingInRadians,
                        Graphics2D context)
```

Class Turtle

Nested Class Summary

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

UNDER_THE_SHELL

NORTH

SOUTH

EAST

WEST

DEFAULT_HEADING_IN_DEGREES

DEFAULT_PEN_COLOR

DEFAULT_PEN_WIDTH

DEFAULT_PEN_DOWN

DEFAULT_HIDDEN

Constructor Detail

Turtle

Turtle

Method Detail

getX

getY

getHeadingInDegrees

getHeadingInRadians

getPenColor

getPenWidth

getPenStroke

isPenDown

isHidden

getTerrarium

setTerrarium

bk

back

fd

forward

move

to

moveTo

tp

teleport

home

rt

right

lt

left

turn

hd

head

pu

penUp

pd

penDown

pc

penColor

pw

penWidth

ht

hide

st

show

draw

drawIcon