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java/org/gannacademy/cdf/turtlelogo/Turtle.java (4 issues)

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package org.gannacademy.cdf.turtlelogo;

import javax.imageio.ImageIO;
import java.awt.*;
import java.awt.geom.AffineTransform;
import java.awt.image.BufferedImage;
import java.io.IOException;

/**
 * <p>A turtles lives in a {@link 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 {@link Track} segments) behind them. The turtles can avoid leaving
 * a track if they pick up their pen.</p>
 *
 * <p><img src="doc-files/trail.png" alt="Turtle leaving a trail"></p>
 *
 * <p>Turtles understand a limited number of instructions:</p>
 *
 * <table style="margin-left: 4em;">
 * <tr>
 * <td><img src="doc-files/move.png" alt="move() example"></td>
 * <td><b>move(</b>
 * <i>steps</i><b>)</b> (a.k.a <i>forward</i> or <i>fd</i> and <i>back</i> or <i>bk</i>) &mdash; the turtle will step
 * forward, in the direction that it is currently facing, some number of steps (i.e. pixels).</td>
 * </tr>
 * <tr>
 * <td><img src="doc-files/turn.png" alt="turn() example"></td>
 * <td><b>turn(</b><i>degrees</i><b>)</b>
 * (a.k.a. <i>left</i> or <i>lt</i> and <i>right</i> or <i>rt</i>) &mdash; the turtle will turn from its current heading
 * some number of degrees.</td>
 * </tr>
 * <tr>
 * <td><img src="doc-files/moveTo.png" alt="moveTo() example"></td>
 * <td><b>moveTo(</b><i>x</i>, <i>y</i><b>)</b> (a.k.a. <i>to</i>) &mdash; the turtle will move from its current
 * location to the coordinates given, without changing its heading.</td>
 * </tr>
 * <tr>
 * <td><img src="doc-files/teleport.png" alt="teleport() example"></td>
 * <td><b>teleport(</b><i>x</i>, <i>y</i><b>)</b> (a.k.a. <i>tp</i>) &mdash; the turtle will teleport (like in Star
 * Trek) from its current location to the new coordinates, without changing its heading <i>and</i> without allowing the
 * pen to drag between locations.</td>
 * </tr>
 * <tr>
 * <td><img src="doc-files/penColor.png" alt="penColor() example"></td>
 * <td><b>penColor(</b><i>color</i><b>)</b> (a.k.a. <i>pc</i>) &mdash; the turtle will change the color of its pen
 * (initially the pen is black)</td>
 * </tr>
 * <tr>
 * <td><img src="doc-files/penWidth.png" alt="penWidth() example"></td>
 * <td><b>penWidth(</b><i>width</i><b>)</b> (a.k.a. <i>pw</i>) &mdash; the turtle will change the width of its pen
 * stroke (measured in pixels)</td>
 * </tr>
 * <tr>
 * <td><img src="doc-files/hide.png" alt="hide() example"></td>
 * <td><b>hide()</b> (a.k.a. <i>ht</i>) &mdash; the turtle will hide itself (but remain at its current location and
 * heading)</td>
 * </tr>
 * <tr>
 * <td><img src="doc-files/show.png" alt="show() example"></td>
 * <td><b>show()</b> (a.k.a. <i>st</i>) &mdash; the turtle, if hidden, will show itself again</td>
 * </tr>
 * <caption>&nbsp;</caption>
 * </table>
 */
public class Turtle {
  /**
   * The parts of the turtle that are "under the shell" are not meant to be used by students. This mechanism
   * (inspired by <a href="https://stackoverflow.com/a/18634125">this awesome Stack Overflow answer</a>) recreates a
   * version of the C++ <code>friend</code> concept: a public method that is only available to <i>some</i> other
   * objects, rather than <i>all</i> other objects.
   *
   * @author <a href="https://github.com/gann-cdf/turtlelogo/issues">Seth Battis</a>
   */
  public static final class UnderTheShell {
    private UnderTheShell() {
    }
  }

  protected static final UnderTheShell UNDER_THE_SHELL = new UnderTheShell();

  /**
   * 270&deg;
   */
  public static final double NORTH = 270;

  /**
   * 90&deg;
   */
  public static final double SOUTH = 90;

  /**
   * 0&deg;
   */
  public static final double EAST = 0;

  /**
   * 180&deg;
   */
  public static final double WEST = 180;

  /**
   * {@link #EAST}
   */
  public static final double DEFAULT_HEADING_IN_DEGREES = EAST; // degrees

  /**
   * {@link java.awt.Color#BLACK}
   */
  public static final Color DEFAULT_PEN_COLOR = Color.BLACK;

  /**
   * 1.0 pixels
   */
  public static final float DEFAULT_PEN_WIDTH = 1;

  /**
   * <code>true</code>
   */
  public static final boolean DEFAULT_PEN_DOWN = true;

  /**
   * <code>false</code>
   */
  public static final boolean DEFAULT_HIDDEN = false;


  private Terrarium terrarium;
  private static BufferedImage icon;

  private double x, y;
  private double headingInDegrees;
  private Color penColor;
  private BasicStroke penStroke;
  private boolean penDown;
  private boolean hidden;

  /**
   * Construct a turtle in the default terrarium
   */
  public Turtle() {
    this(Terrarium.getInstance());
  }

  /**
   * Construct a turtle in a custom terrarium
   *
   * @param terrarium to house the turtle
   */
  public Turtle(Terrarium terrarium) {
    this.x = terrarium.getWidth() / 2.0;
    this.y = terrarium.getHeight() / 2.0;
    this.headingInDegrees = DEFAULT_HEADING_IN_DEGREES;
    this.penColor = DEFAULT_PEN_COLOR;
    this.penStroke = new BasicStroke(DEFAULT_PEN_WIDTH);
    this.penDown = DEFAULT_PEN_DOWN;
    this.hidden = DEFAULT_HIDDEN;
    this.terrarium = terrarium;
    this.terrarium.add(this, UNDER_THE_SHELL);
  }

  /**
   * @return X-coordinate of turtle
   */
  public double getX() {
    return x;
  }

  /**
   * @return Y-coordinate of turtle
   */
  public double getY() {
    return y;
  }

  /**
   * @return Current turtle heading in degrees
   */
  public double getHeadingInDegrees() {
    return headingInDegrees;
  }

  /**
   * @return Current turtle heading in radians
   */
  public double getHeadingInRadians() {
    return Math.toRadians(headingInDegrees);
  }

  /**
   * @return Current pen color
   */
  public Color getPenColor() {
    return penColor;
  }

  /**
   * @return Current pen width
   */
  public double getPenWidth() {
    return penStroke.getLineWidth();
  }

  protected BasicStroke getPenStroke() {
    return penStroke;
  }

  /**
   * @return <code>true</code> if the pen is down, <code>false</code> otherwise
   */
  public boolean isPenDown() {
    return penDown;
  }

  /**
   * @return <code>true</code> if the turtle is hidden, <code>false</code> otherwise
   */
  public boolean isHidden() {
    return hidden;
  }

  private BufferedImage getIcon() {
    if (icon == null) {
      try {
        icon = ImageIO.read(getClass().getResource("/turtle.png"));

      } catch (IOException e) {
        System.err.println("The image file containing the turtle icon could not be found and/or opened.");
        e.printStackTrace();

      }
    }
    return icon;
  }

  /**
   * @return Terrarium currently housing the turtle
   */
  public Terrarium getTerrarium() {
    return terrarium;
  }

  /**
   * Move the turtle to another terrarium
   *
   * @param terrarium to house the turtle
   */
  public void setTerrarium(Terrarium terrarium) {
    if (this.terrarium != null) {
      this.terrarium.remove(this, UNDER_THE_SHELL);
    }
    this.terrarium = terrarium;
    terrarium.add(this, UNDER_THE_SHELL);
  }

  /**
   * Alias for {@link #back(double)}
   *
   * @param steps in pixels
   */
  public void bk(double steps) {
    back(steps);
  }

  /**
   * Alias for {@link #move(double)}
   *
   * @param steps in pixels
   */
  public void back(double steps) {
    move(-1 * steps);
  }

  /**
   * Alias for {@link #forward(double)}
   *
   * @param steps in pixels
   */
  public void fd(double steps) {
    forward(steps);
  }

  /**
   * Alias for {@link #move(double)}
   *
   * @param steps in pixels
   */
  public void forward(double steps) {
    move(steps);
  }

  /**
   * <p>Move the turtle in the direction of its current heading</p>
   * <p>A positive value for <code>steps</code> is interpreted as forward movement and a negative value as backward
   * movement</p>
   *
   * @param steps in pixels
   */
  public void move(double steps) {
    double newX = x + Math.cos(getHeadingInRadians()) * steps,
            newY = y + Math.sin(getHeadingInRadians()) * steps;
    if (penDown) {
      getTerrarium().add(new Track(x, y, newX, newY, penColor, penStroke, UNDER_THE_SHELL), UNDER_THE_SHELL);
    }
    x = newX;
    y = newY;
  }

  /**
   * Alias for {@link #moveTo(double, double)}
   *
   * @param x coordinate
   * @param y coordinate
   */
  public void to(double x, double y) {
    moveTo(x, y);
  }

  /**
   * <p>Move the turtle to a particular location</p>
   * <p>The turtle moves directly to the window coordinates (<code>x</code>, <code>y</code>). 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 <i>from to to bottom</i>.</p>
   * <p>If the turtle's pen is currently down, the move will create a track from the old location to the new location.</p>
   *
   * @param x coordinate
   * @param y coordinate
   */
  public void moveTo(double x, double y) {
    if (penDown) {
      getTerrarium().add(new Track(this.x, this.y, x, y, penColor, penStroke, UNDER_THE_SHELL), UNDER_THE_SHELL);
    }
    this.x = x;
    this.y = y;
  }

  /**
   * Alias for {@link #teleport(double, double)}
   *
   * @param x coordinate
   * @param y coordinate
   */
  public void tp(double x, double y) {
    teleport(x, y);
  }

  /**
   * <p>Move the turtle instantaneously to a particular location</p>
   * <p>The turtle moves directly to the window coordinates (<code>x</code>, <code>y</code>). 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 <i>from to to bottom</i>.</p>
   * <p>No track is left by a teleportation.</p>
   *
   * @param x coordinate
   * @param y coordinate
   */
  public void teleport(double x, double y) {
    this.x = x;
    this.y = y;
  }

  /**
   * <p>Reset the turtle to its home position</p>
   * <p>The turtle's home position is at the center of the window, heading {@link #EAST}</p>
   */
  public void home() {
    teleport(getTerrarium().getWidth() / 2.0, getTerrarium().getHeight() / 2.0);
    head(EAST);
  }

  /**
   * Alias for {@link #right(double)}
   *
   * @param angle in degrees
   */
  public void rt(double angle) {
    right(angle);
  }

  /**
   * Alias for {@link #turn(double)}
   *
   * @param angle in degrees
   */
  public void right(double angle) {
    turn(angle);
  }

  /**
   * Alias for {@link #left(double)}
   *
   * @param angle in degrees
   */
  public void lt(double angle) {
    left(angle);
  }

  /**
   * Alias for {@link #turn(double)}
   *
   * @param angle in degrees
   */
  public void left(double angle) {
    turn(-1 * angle);
  }

  /**
   * <p>Turn the turtle from its current heading</p>
   * <p>A positive angle is interpreted as a <i>right</i> 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&deg; at the {@link #SOUTH} and270&deg; at the
   * {@link #NORTH}</p>
   *
   * @param angle in degrees
   */
  public void turn(double angle) {
    headingInDegrees = (headingInDegrees + angle) % 360;
    getTerrarium().repaint();
  }

  /**
   * Alias for {@link #head(double)}
   *
   * @param heading in degrees
   */
  public void hd(double heading) {
    head(heading);
  }

  /**
   * <p>Turn the turtle to a particular heading</p>
   * <p>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&deg; at the {@link #SOUTH} and 270%deg; at the {@link #NORTH}.
   * Convenience constants have been provided for the cardinal directions.</p>
   *
   * @param heading [0..360) in degrees
   */
  public void head(double heading) {
    this.headingInDegrees = heading % 360;
  }

  /**
   * Alis for {@link #penUp()}
   */
  public void pu() {
    penUp();
  }

  /**
   * Lift the turtle's pen up, causing it not to leave a track
   */
  public void penUp() {
    penDown = false;
  }

  /**
   * Alias for {@link #penDown()}
   */
  public void pd() {
    penDown();
  }

  /**
   * Lower the turtle's pen, causing it to leave a trail
   */
  public void penDown() {
    penDown = true;
  }

  /**
   * Alias for {@link #penColor(Color)}
   *
   * @param color to use
   */
  public void pc(Color color) {
    penColor(color);
  }

  /**
   * <p>Set the color of the turtle's pen</p>
   * <p>Color values are given as {@link Color} values. {@link Color} has a number of helpful constants like
   * {@link Color#GREEN} or {@link Color#GREEN}. Custom colors can also be constructed. Refer to the
   * <a href="https://docs.oracle.com/javase/10/docs/api/java/awt/Color.html" target="_blank">j<code>ava.awt.Color</code>
   * API documentation</a> more details (including how to create transparent colors!)</p>
   *
   * @param color to use
   */
  public void penColor(Color color) {
    penColor = color;
  }

  /**
   * Alias for {@link #penWidth(double)}
   *
   * @param width in pixels
   */
  public void pw(double width) {
    penWidth(width);
  }

  /**
   * Set the width of the turtle's pen
   *
   * @param width in pixels
   */
  public void penWidth(double width) {
    penStroke = new BasicStroke((float) width, BasicStroke.CAP_ROUND, BasicStroke.JOIN_ROUND);
  }

  /**
   * Alias for {@link #hide()}
   */
  public void ht() {
    hide();
  }

  /**
   * <p>Hide the turtle</p>
   * <p>Hiding the turtle causes it to become invisible &mdash; it can still be moved and create tracks, but the turtle
   * itself is not visible</p>
   */
  public void hide() {
    hidden = true;
    getTerrarium().repaint();
  }

  /**
   * Alias for {@link #show()}
   */
  public void st() {
    show();
  }

  /**
   * Show the turtle (if it was hidden)
   */
  public void show() {
    hidden = false;
    getTerrarium().repaint();
  }

  /**
   * <p>Draw the turtle</p>
   * <p>May only be called by {@link Terrarium} and its subclasses, enforced by {@link Terrarium.UnderTheSurface}</p>
   *
   * @param context for drawing commands
   * @param key     to authenticate "Terrarium-iality"
   */
  public void draw(Graphics2D context, Terrarium.UnderTheSurface key) {
    key.hashCode();
    drawIcon(x, y, getHeadingInRadians(), context);
  }

  protected void drawIcon(double x, double y, double headingInRadians, Graphics2D context) {
    if (!hidden) {
      AffineTransform transform = new AffineTransform(); // transformations are applied in reverse order
      transform.translate(x, y); // move turtle to location
      transform.rotate(headingInRadians); // orient turtle to heading
      transform.translate(-1 * getIcon().getWidth(), getIcon().getHeight() / -2.0); // move icon origin to turtle nose

      context.drawImage(getIcon(), transform, null);
    }
  }
}


1			package org.gannacademy.cdf.turtlelogo;
2
3			import javax.imageio.ImageIO;
4			import java.awt.*;
5			import java.awt.geom.AffineTransform;
6			import java.awt.image.BufferedImage;
7			import java.io.IOException;
8
9			/**
10			* <p>A turtles lives in a {@link Terrarium}. We imagine that turtles all hold a pen in their mouth. As they walk around
11			* the terrarium, they leave a trail (a series of {@link Track} segments) behind them. The turtles can avoid leaving
12			* a track if they pick up their pen.</p>
13			*
14			* <p><img src="doc-files/trail.png" alt="Turtle leaving a trail"></p>
15			*
16			* <p>Turtles understand a limited number of instructions:</p>
17			*
18			* <table style="margin-left: 4em;">
19			* <tr>
20			* <td><img src="doc-files/move.png" alt="move() example"></td>
21			* <td><b>move(</b>
22			* <i>steps</i><b>)</b> (a.k.a <i>forward</i> or <i>fd</i> and <i>back</i> or <i>bk</i>) — the turtle will step
23			* forward, in the direction that it is currently facing, some number of steps (i.e. pixels).</td>
24			* </tr>
25			* <tr>
26			* <td><img src="doc-files/turn.png" alt="turn() example"></td>
27			* <td><b>turn(</b><i>degrees</i><b>)</b>
28			* (a.k.a. <i>left</i> or <i>lt</i> and <i>right</i> or <i>rt</i>) — the turtle will turn from its current heading
29			* some number of degrees.</td>
30			* </tr>
31			* <tr>
32			* <td><img src="doc-files/moveTo.png" alt="moveTo() example"></td>
33			* <td><b>moveTo(</b><i>x</i>, <i>y</i><b>)</b> (a.k.a. <i>to</i>) — the turtle will move from its current
34			* location to the coordinates given, without changing its heading.</td>
35			* </tr>
36			* <tr>
37			* <td><img src="doc-files/teleport.png" alt="teleport() example"></td>
38			* <td><b>teleport(</b><i>x</i>, <i>y</i><b>)</b> (a.k.a. <i>tp</i>) — the turtle will teleport (like in Star
39			* Trek) from its current location to the new coordinates, without changing its heading <i>and</i> without allowing the
40			* pen to drag between locations.</td>
41			* </tr>
42			* <tr>
43			* <td><img src="doc-files/penColor.png" alt="penColor() example"></td>
44			* <td><b>penColor(</b><i>color</i><b>)</b> (a.k.a. <i>pc</i>) — the turtle will change the color of its pen
45			* (initially the pen is black)</td>
46			* </tr>
47			* <tr>
48			* <td><img src="doc-files/penWidth.png" alt="penWidth() example"></td>
49			* <td><b>penWidth(</b><i>width</i><b>)</b> (a.k.a. <i>pw</i>) — the turtle will change the width of its pen
50			* stroke (measured in pixels)</td>
51			* </tr>
52			* <tr>
53			* <td><img src="doc-files/hide.png" alt="hide() example"></td>
54			* <td><b>hide()</b> (a.k.a. <i>ht</i>) — the turtle will hide itself (but remain at its current location and
55			* heading)</td>
56			* </tr>
57			* <tr>
58			* <td><img src="doc-files/show.png" alt="show() example"></td>
59			* <td><b>show()</b> (a.k.a. <i>st</i>) — the turtle, if hidden, will show itself again</td>
60			* </tr>
61			* <caption> </caption>
62			* </table>
63			*/
64			public class Turtle {
65			/**
66			* The parts of the turtle that are "under the shell" are not meant to be used by students. This mechanism
67			* (inspired by <a href="https://stackoverflow.com/a/18634125">this awesome Stack Overflow answer</a>) recreates a
68			* version of the C++ <code>friend</code> concept: a public method that is only available to <i>some</i> other
69			* objects, rather than <i>all</i> other objects.
70			*
71			* @author <a href="https://github.com/gann-cdf/turtlelogo/issues">Seth Battis</a>
72			*/
73			public static final class UnderTheShell {
74			private UnderTheShell() {
75			}
76			}
77
78			protected static final UnderTheShell UNDER_THE_SHELL = new UnderTheShell();
79
80			/**
81			* 270°
82			*/
83			public static final double NORTH = 270;
84
85			/**
86			* 90°
87			*/
88			public static final double SOUTH = 90;
89
90			/**
91			* 0°
92			*/
93			public static final double EAST = 0;
94
95			/**
96			* 180°
97			*/
98			public static final double WEST = 180;
99
100			/**
101			* {@link #EAST}
102			*/
103			public static final double DEFAULT_HEADING_IN_DEGREES = EAST; // degrees
104
105			/**
106			* {@link java.awt.Color#BLACK}
107			*/
108			public static final Color DEFAULT_PEN_COLOR = Color.BLACK;
109
110			/**
111			* 1.0 pixels
112			*/
113			public static final float DEFAULT_PEN_WIDTH = 1;
114
115			/**
116			* <code>true</code>
117			*/
118			public static final boolean DEFAULT_PEN_DOWN = true;
119
120			/**
121			* <code>false</code>
122			*/
123			public static final boolean DEFAULT_HIDDEN = false;
124
125
126			private Terrarium terrarium;
127			private static BufferedImage icon;
128
129			private double x, y;
130			private double headingInDegrees;
131			private Color penColor;
132			private BasicStroke penStroke;
133			private boolean penDown;
134			private boolean hidden;
135
136			/**
137			* Construct a turtle in the default terrarium
138			*/
139			public Turtle() {
140			this(Terrarium.getInstance());
141			}
142
143			/**
144			* Construct a turtle in a custom terrarium
145			*
146			* @param terrarium to house the turtle
147			*/
148			public Turtle(Terrarium terrarium) {
149			this.x = terrarium.getWidth() / 2.0;
150			this.y = terrarium.getHeight() / 2.0;
151			this.headingInDegrees = DEFAULT_HEADING_IN_DEGREES;
152			this.penColor = DEFAULT_PEN_COLOR;
153			this.penStroke = new BasicStroke(DEFAULT_PEN_WIDTH);
154			this.penDown = DEFAULT_PEN_DOWN;
155			this.hidden = DEFAULT_HIDDEN;
156			this.terrarium = terrarium;
157			this.terrarium.add(this, UNDER_THE_SHELL);
158			}
159
160			/**
161			* @return X-coordinate of turtle
162			*/
163			public double getX() {
164			return x;
165			}
166
167			/**
168			* @return Y-coordinate of turtle
169			*/
170			public double getY() {
171			return y;
172			}
173
174			/**
175			* @return Current turtle heading in degrees
176			*/
177			public double getHeadingInDegrees() {
178			return headingInDegrees;
179			}
180
181			/**
182			* @return Current turtle heading in radians
183			*/
184			public double getHeadingInRadians() {
185			return Math.toRadians(headingInDegrees);
186			}
187
188			/**
189			* @return Current pen color
190			*/
191			public Color getPenColor() {
192			return penColor;
193			}
194
195			/**
196			* @return Current pen width
197			*/
198			public double getPenWidth() {
199			return penStroke.getLineWidth();
200			}
201
202			protected BasicStroke getPenStroke() {
203			return penStroke;
204			}
205
206			/**
207			* @return <code>true</code> if the pen is down, <code>false</code> otherwise
208			*/
209			public boolean isPenDown() {
210			return penDown;
211			}
212
213			/**
214			* @return <code>true</code> if the turtle is hidden, <code>false</code> otherwise
215			*/
216			public boolean isHidden() {
217			return hidden;
218			}
219
220			private BufferedImage getIcon() {
221			if (icon == null) {
222			try {
223			icon = ImageIO.read(getClass().getResource("/turtle.png"));
			0 ignored issues – show Bug Multi Threading introduced 2018-08-30 17:32 UTC by Report Bug Copy Issue Report Show Similar Issues like this Instance methods writing to static fields may lead to concurrency problems. Consider making the enclosing method static or removing this assignment to a static field. If you really need to set this static field, consider writing a thread-safe setter and atomic getter. Loading history...
224			} catch (IOException e) {
225			System.err.println("The image file containing the turtle icon could not be found and/or opened.");
226			e.printStackTrace();
			0 ignored issues – show Best Practice introduced 2018-07-17 18:02 UTC by Report Bug Copy Issue Report Show Similar Issues like this Throwable.printStackTrace writes to the console which might not be available at runtime. Using a logger is preferred. Loading history...
227			}
228			}
229			return icon;
230			}
231
232			/**
233			* @return Terrarium currently housing the turtle
234			*/
235			public Terrarium getTerrarium() {
236			return terrarium;
237			}
238
239			/**
240			* Move the turtle to another terrarium
241			*
242			* @param terrarium to house the turtle
243			*/
244			public void setTerrarium(Terrarium terrarium) {
245			if (this.terrarium != null) {
246			this.terrarium.remove(this, UNDER_THE_SHELL);
247			}
248			this.terrarium = terrarium;
249			terrarium.add(this, UNDER_THE_SHELL);
250			}
251
252			/**
253			* Alias for {@link #back(double)}
254			*
255			* @param steps in pixels
256			*/
257			public void bk(double steps) {
258			back(steps);
259			}
260
261			/**
262			* Alias for {@link #move(double)}
263			*
264			* @param steps in pixels
265			*/
266			public void back(double steps) {
267			move(-1 * steps);
268			}
269
270			/**
271			* Alias for {@link #forward(double)}
272			*
273			* @param steps in pixels
274			*/
275			public void fd(double steps) {
276			forward(steps);
277			}
278
279			/**
280			* Alias for {@link #move(double)}
281			*
282			* @param steps in pixels
283			*/
284			public void forward(double steps) {
285			move(steps);
286			}
287
288			/**
289			* <p>Move the turtle in the direction of its current heading</p>
290			* <p>A positive value for <code>steps</code> is interpreted as forward movement and a negative value as backward
291			* movement</p>
292			*
293			* @param steps in pixels
294			*/
295			public void move(double steps) {
296			double newX = x + Math.cos(getHeadingInRadians()) * steps,
297			newY = y + Math.sin(getHeadingInRadians()) * steps;
298			if (penDown) {
299			getTerrarium().add(new Track(x, y, newX, newY, penColor, penStroke, UNDER_THE_SHELL), UNDER_THE_SHELL);
300			}
301			x = newX;
302			y = newY;
303			}
304
305			/**
306			* Alias for {@link #moveTo(double, double)}
307			*
308			* @param x coordinate
309			* @param y coordinate
310			*/
311			public void to(double x, double y) {
312			moveTo(x, y);
313			}
314
315			/**
316			* <p>Move the turtle to a particular location</p>
317			* <p>The turtle moves directly to the window coordinates (<code>x</code>, <code>y</code>). Note that the origin of
318			* the wind ow is in the top, left corner and that, while the X-axis increases from left to right, the Y-axis
319			* increases <i>from to to bottom</i>.</p>
320			* <p>If the turtle's pen is currently down, the move will create a track from the old location to the new location.</p>
321			*
322			* @param x coordinate
323			* @param y coordinate
324			*/
325			public void moveTo(double x, double y) {
326			if (penDown) {
327			getTerrarium().add(new Track(this.x, this.y, x, y, penColor, penStroke, UNDER_THE_SHELL), UNDER_THE_SHELL);
328			}
329			this.x = x;
330			this.y = y;
331			}
332
333			/**
334			* Alias for {@link #teleport(double, double)}
335			*
336			* @param x coordinate
337			* @param y coordinate
338			*/
339			public void tp(double x, double y) {
340			teleport(x, y);
341			}
342
343			/**
344			* <p>Move the turtle instantaneously to a particular location</p>
345			* <p>The turtle moves directly to the window coordinates (<code>x</code>, <code>y</code>). Note that the origin of
346			* the wind ow is in the top, left corner and that, while the X-axis increases from left to right, the Y-axis
347			* increases <i>from to to bottom</i>.</p>
348			* <p>No track is left by a teleportation.</p>
349			*
350			* @param x coordinate
351			* @param y coordinate
352			*/
353			public void teleport(double x, double y) {
354			this.x = x;
355			this.y = y;
356			}
357
358			/**
359			* <p>Reset the turtle to its home position</p>
360			* <p>The turtle's home position is at the center of the window, heading {@link #EAST}</p>
361			*/
362			public void home() {
363			teleport(getTerrarium().getWidth() / 2.0, getTerrarium().getHeight() / 2.0);
364			head(EAST);
365			}
366
367			/**
368			* Alias for {@link #right(double)}
369			*
370			* @param angle in degrees
371			*/
372			public void rt(double angle) {
373			right(angle);
374			}
375
376			/**
377			* Alias for {@link #turn(double)}
378			*
379			* @param angle in degrees
380			*/
381			public void right(double angle) {
382			turn(angle);
383			}
384
385			/**
386			* Alias for {@link #left(double)}
387			*
388			* @param angle in degrees
389			*/
390			public void lt(double angle) {
391			left(angle);
392			}
393
394			/**
395			* Alias for {@link #turn(double)}
396			*
397			* @param angle in degrees
398			*/
399			public void left(double angle) {
400			turn(-1 * angle);
401			}
402
403			/**
404			* <p>Turn the turtle from its current heading</p>
405			* <p>A positive angle is interpreted as a <i>right</i> turn and a negative angle is a left turn. This is mildly
406			* surprising if you know about the unit circle, but is because the Y-axis of the window increases from top to bottom,
407			* which results in a mirrored unit circle around the X-axis, with 90° at the {@link #SOUTH} and270° at the
408			* {@link #NORTH}</p>
409			*
410			* @param angle in degrees
411			*/
412			public void turn(double angle) {
413			headingInDegrees = (headingInDegrees + angle) % 360;
414			getTerrarium().repaint();
415			}
416
417			/**
418			* Alias for {@link #head(double)}
419			*
420			* @param heading in degrees
421			*/
422			public void hd(double heading) {
423			head(heading);
424			}
425
426			/**
427			* <p>Turn the turtle to a particular heading</p>
428			* <p>Note that, because the Y-axis of the window increases from top to bottom, the usual angles of the unit circle
429			* have been mirrored around the X-axis, with 90° at the {@link #SOUTH} and 270%deg; at the {@link #NORTH}.
430			* Convenience constants have been provided for the cardinal directions.</p>
431			*
432			* @param heading [0..360) in degrees
433			*/
434			public void head(double heading) {
435			this.headingInDegrees = heading % 360;
436			}
437
438			/**
439			* Alis for {@link #penUp()}
440			*/
441			public void pu() {
442			penUp();
443			}
444
445			/**
446			* Lift the turtle's pen up, causing it not to leave a track
447			*/
448			public void penUp() {
449			penDown = false;
450			}
451
452			/**
453			* Alias for {@link #penDown()}
454			*/
455			public void pd() {
456			penDown();
457			}
458
459			/**
460			* Lower the turtle's pen, causing it to leave a trail
461			*/
462			public void penDown() {
463			penDown = true;
464			}
465
466			/**
467			* Alias for {@link #penColor(Color)}
468			*
469			* @param color to use
470			*/
471			public void pc(Color color) {
472			penColor(color);
473			}
474
475			/**
476			* <p>Set the color of the turtle's pen</p>
477			* <p>Color values are given as {@link Color} values. {@link Color} has a number of helpful constants like
478			* {@link Color#GREEN} or {@link Color#GREEN}. Custom colors can also be constructed. Refer to the
479			* <a href="https://docs.oracle.com/javase/10/docs/api/java/awt/Color.html" target="_blank">j<code>ava.awt.Color</code>
480			* API documentation</a> more details (including how to create transparent colors!)</p>
481			*
482			* @param color to use
483			*/
484			public void penColor(Color color) {
485			penColor = color;
486			}
487
488			/**
489			* Alias for {@link #penWidth(double)}
490			*
491			* @param width in pixels
492			*/
493			public void pw(double width) {
494			penWidth(width);
495			}
496
497			/**
498			* Set the width of the turtle's pen
499			*
500			* @param width in pixels
501			*/
502			public void penWidth(double width) {
503			penStroke = new BasicStroke((float) width, BasicStroke.CAP_ROUND, BasicStroke.JOIN_ROUND);
504			}
505
506			/**
507			* Alias for {@link #hide()}
508			*/
509			public void ht() {
510			hide();
511			}
512
513			/**
514			* <p>Hide the turtle</p>
515			* <p>Hiding the turtle causes it to become invisible — it can still be moved and create tracks, but the turtle
516			* itself is not visible</p>
517			*/
518			public void hide() {
519			hidden = true;
520			getTerrarium().repaint();
521			}
522
523			/**
524			* Alias for {@link #show()}
525			*/
526			public void st() {
527			show();
528			}
529
530			/**
531			* Show the turtle (if it was hidden)
532			*/
533			public void show() {
534			hidden = false;
535			getTerrarium().repaint();
536			}
537
538			/**
539			* <p>Draw the turtle</p>
540			* <p>May only be called by {@link Terrarium} and its subclasses, enforced by {@link Terrarium.UnderTheSurface}</p>
541			*
542			* @param context for drawing commands
543			* @param key to authenticate "Terrarium-iality"
544			*/
545			public void draw(Graphics2D context, Terrarium.UnderTheSurface key) {
546			key.hashCode();
547			drawIcon(x, y, getHeadingInRadians(), context);
548			}
549
550			protected void drawIcon(double x, double y, double headingInRadians, Graphics2D context) {
551			if (!hidden) {
552			AffineTransform transform = new AffineTransform(); // transformations are applied in reverse order
553			transform.translate(x, y); // move turtle to location
554			transform.rotate(headingInRadians); // orient turtle to heading
555			transform.translate(-1 * getIcon().getWidth(), getIcon().getHeight() / -2.0); // move icon origin to turtle nose
			0 ignored issues – show Bug introduced 2018-07-17 18:02 UTC by Report Bug Copy Issue Report Show Similar Issues like this Math operands should be cast to prevent unwanted loss of precision when mixing types. Consider casting one of the operands of this multiplication to double. Loading history... Security Bug introduced 2018-07-17 18:02 UTC by Report Bug Copy Issue Report Show Similar Issues like this A "NullPointerException" could be thrown; "getIcon" is nullable here. Loading history...
556			context.drawImage(getIcon(), transform, null);
557			}
558			}
559			}
560

gann-cdf / turtle-logo

Issues (37)

java/org/gannacademy/cdf/turtlelogo/Turtle.java (4 issues)

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