Question

Modify the NervousShapes program so that it displays equilateral triangles as well as circles and rectangles. You will need to define a Triangle class containing a single instance variable, representing the length of one of the triangle’s sides. Have the program create circles, rectangles, and triangles with equal probability. Circle and Rectangle is done, please comment on your methods so i can understand

*/
package NervousShapes;

import java.awt.*;
import java.awt.event.*;
import java.awt.image.*;
import javax.imageio.*;
import javax.swing.*;
import javax.swing.event.*;

public class DrawingPanel implements ActionListener {
    public static final int DELAY = 50; // delay between repaints in millis

    private static final String DUMP_IMAGE_PROPERTY_NAME = "drawingpanel.save";
    private static String TARGET_IMAGE_FILE_NAME = null;
    private static final boolean PRETTY = true; // true to anti-alias
    private static boolean DUMP_IMAGE = true; // true to write DrawingPanel to file

    private int width, height;    // dimensions of window frame
    private JFrame frame;         // overall window frame
    private JPanel panel;         // overall drawing surface
    private BufferedImage image; // remembers drawing commands
    private Graphics2D g2;        // graphics context for painting
    private JLabel statusBar;     // status bar showing mouse position
    private long createTime;

    static {
        TARGET_IMAGE_FILE_NAME = System.getProperty(DUMP_IMAGE_PROPERTY_NAME);
        DUMP_IMAGE = (TARGET_IMAGE_FILE_NAME != null);
    }

    // construct a drawing panel of given width and height enclosed in a window
    public DrawingPanel(int width, int height) {
        this.width = width;
        this.height = height;
        this.image = new BufferedImage(width, height, BufferedImage.TYPE_INT_ARGB);

        this.statusBar = new JLabel(" ");
        this.statusBar.setBorder(BorderFactory.createLineBorder(Color.BLACK));

        this.panel = new JPanel(new FlowLayout(FlowLayout.CENTER, 0, 0));
        this.panel.setBackground(Color.WHITE);
        this.panel.setPreferredSize(new Dimension(width, height));
        this.panel.add(new JLabel(new ImageIcon(image)));

        // listen to mouse movement
        MouseInputAdapter listener = new MouseInputAdapter() {
            public void mouseMoved(MouseEvent e) {
                DrawingPanel.this.statusBar.setText("(" + e.getX() + ", " + e.getY() + ")");
            }

            public void mouseExited(MouseEvent e) {
                DrawingPanel.this.statusBar.setText(" ");
            }
        };
        this.panel.addMouseListener(listener);
        this.panel.addMouseMotionListener(listener);

        this.g2 = (Graphics2D)image.getGraphics();
        this.g2.setColor(Color.BLACK);
        if (PRETTY) {
            this.g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
            this.g2.setStroke(new BasicStroke(1.1f));
        }

        this.frame = new JFrame("Building Java Programs - Drawing Panel");
        this.frame.setResizable(false);
        this.frame.addWindowListener(new WindowAdapter() {
            public void windowClosing(WindowEvent e) {
                if (DUMP_IMAGE) {
                    DrawingPanel.this.save(TARGET_IMAGE_FILE_NAME);
                }
                System.exit(0);
            }
        });
        this.frame.getContentPane().add(panel);
        this.frame.getContentPane().add(statusBar, "South");
        this.frame.pack();
        this.frame.setVisible(true);
        if (DUMP_IMAGE) {
            createTime = System.currentTimeMillis();
            this.frame.toBack();
        } else {
            this.toFront();
        }

        // repaint timer so that the screen will update
        new Timer(DELAY, this).start();
    }

    // used for an internal timer that keeps repainting
    public void actionPerformed(ActionEvent e) {
        this.panel.repaint();
        if (DUMP_IMAGE && System.currentTimeMillis() > createTime + 4 * DELAY) {
            this.frame.setVisible(false);
            this.frame.dispose();
            this.save(TARGET_IMAGE_FILE_NAME);
            System.exit(0);
        }
    }

    // obtain the Graphics object to draw on the panel
    public Graphics2D getGraphics() {
        return this.g2;
    }

    // set the background color of the drawing panel
    public void setBackground(Color c) {
        this.panel.setBackground(c);
    }

-----------------------------------------------------------------------------------

// Displays a frame containing a random mixture of circles
// and rectangles with random colors, sizes, and positions.
// The shapes periodically change position, with the
// direction of motion chosen randomly for each shape. The
// new x coordinate for each shape will either be the same
// as the old x coordinate, one pixel smaller, or one pixel
// larger; the new y coordinate will be computed in a
// similar manner. Shapes will be constrained so that they
// do not move outside the drawing area.
package NervousShapes;

import java.awt.*;

public class NervousShapes {
// Constants
private static final int DELAY = 100;
    // Animation delay (milliseconds)
private static final int MAX_SIZE = 40;
    // Maximum width and height of a shape
private static final int MIN_SIZE = 10;
    // Minimum width and height of a shape
private static final int NUM_SHAPES = 90;
    // Number of shapes
private static final int WINDOW_SIZE = 400;
    // Width and height of drawable portion of frame

private static final int CHANGE_RANGE = 2;
// how far the new position can be from the previous position

private static DrawingPanel panel;
private static Graphics g;
    // Graphics context for frame
private static Shape shapes[] = new Shape[NUM_SHAPES];
    // Array of shapes

public static void main(String[] args) {
    createWindow();
    createShapes();
    animateShapes();
}

///////////////////////////////////////////////////////////
// NAME:       createWindow
// BEHAVIOR:   Creates a frame labeled "Nervous Shapes",
//             displays the frame, and sets the size of
//             the frame (using the WINDOW_SIZE class
//             variable). Assigns the frame to the df
//             class variable, and assigns the frame's
//             graphics context to the g class variable.
// PARAMETERS: None
// RETURNS:    Nothing
///////////////////////////////////////////////////////////
private static void createWindow() {
    // Create the drawing panel
   panel = new DrawingPanel(WINDOW_SIZE, WINDOW_SIZE);

    // Get the graphics context
    g = panel.getGraphics();
}

///////////////////////////////////////////////////////////
// NAME:       createShapes
// BEHAVIOR:   Creates enough Circle and Rectangle objects
//             to fill the shapes array. Each shape has a
//             random color, size, and position. The height
//             and width of each shape must lie between
//             MIN_SIZE and MAX_SIZE (inclusive). The
//             position is chosen so that the shape is
//             completely within the drawing area.
// PARAMETERS: None
// RETURNS:    Nothing
///////////////////////////////////////////////////////////
private static void createShapes() {
    for (int i = 0; i < shapes.length; i++) {
      // Select a random color
      int red = generateRandomInt(0, 255);
      int green = generateRandomInt(0, 255);
      int blue = generateRandomInt(0, 255);
      Color color = new Color(red, green, blue);
      // Decide whether to create a circle or a rectangle
      if (Math.random() < 0.5) {
        // Generate a circle with a random size and position
        int diameter = generateRandomInt(MIN_SIZE, MAX_SIZE);
        int x = generateRandomInt(0, WINDOW_SIZE - diameter);
        int y = generateRandomInt(0, WINDOW_SIZE - diameter);
        shapes[i] = new Circle(x, y, color, diameter);
      } else {
        // Generate a rectangle with a random size and
        // position
        int width = generateRandomInt(MIN_SIZE, MAX_SIZE);
        int height = generateRandomInt(MIN_SIZE, MAX_SIZE);
        int x = generateRandomInt(0, WINDOW_SIZE - width);
        int y = generateRandomInt(0, WINDOW_SIZE - height);
        shapes[i] = new Rectangle(x, y, color, width, height);
      }
    }
}

///////////////////////////////////////////////////////////
// NAME:       animateShapes
// BEHAVIOR:   Establishes an infinite loop in which the
//             shapes are animated. During each loop
//             iteration, the drawing area is cleared and
//             the shapes are then drawn at new positions.
//             The new x and y coordinates for each shape
//             will either be the same as the old ones,
//             one pixel smaller, or one pixel larger. A
//             shape is not moved if doing so would cause
//             any portion of the shape to go outside the
//             drawing area. At the end of each animation
//             cycle, there is a brief pause, which is
//             controlled by the delay constant.
// PARAMETERS: None
// RETURNS:    Nothing
///////////////////////////////////////////////////////////
private static void animateShapes() {
    while (true) {
      // Clear drawing area
      g.setColor(Color.white);
      g.fillRect(0, 0, WINDOW_SIZE - 1, WINDOW_SIZE - 1);
      for (int i = 0; i < shapes.length; i++) {
        // Change the x coordinate for shape i
        int dx = generateRandomInt(-CHANGE_RANGE, +CHANGE_RANGE);
        int newX = shapes[i].getX() + dx;
        if (newX >= 0 &&
            newX + shapes[i].getWidth() < WINDOW_SIZE)
          shapes[i].move(dx, 0);

        // Change the y coordinate for shape i
        int dy = generateRandomInt(-CHANGE_RANGE, +CHANGE_RANGE);
        int newY = shapes[i].getY() + dy;
        if (newY >= 0 &&
            newY + shapes[i].getHeight() < WINDOW_SIZE)
          shapes[i].move(0, dy);

        // Draw shape i at its new position
        shapes[i].draw(g);
      }
    
      panel.sleep(DELAY);

    }
}

///////////////////////////////////////////////////////////
// NAME:       generateRandomInt
// BEHAVIOR:   Generates a random integer within a
//             specified range.
// PARAMETERS: min - the lower bound of the range
//             max - the upper bound of the range
// RETURNS:    A random integer that is greater than or
//             equal to min and less than or equal to max
///////////////////////////////////////////////////////////
private static int generateRandomInt(int min, int max) {
    return (int) ((max - min + 1) * Math.random()) + min;
}
}
---------------------------------------------------------------------------

package NervousShapes;

import java.awt.*;

public class Rectangle extends Shape {
// Instance variables
private int width;
private int height;

// Constructor
public Rectangle(int x, int y, Color color,
                   int width, int height) {
    super(x, y, color);
    this.width = width;
    this.height = height;
}
// Instance methods
public void draw(Graphics g) {
    g.setColor(getColor());
    g.fillRect(getX(), getY(), width, height);
}

public int getHeight() {
    return height;
}

public int getWidth() {
    return width;
}
}
----------------------------------------------------------------------

package NervousShapes;

import java.awt.*;

public abstract class Shape {
// Instance variables
private int x;
private int y;
private Color color;

// Constructor
protected Shape(int x, int y, Color color) {
    this.x = x;
    this.y = y;
    this.color = color;
}
// Abstract methods
public abstract void draw(Graphics g);
public abstract int getHeight();
public abstract int getWidth();

// Other instance methods
public Color getColor() {
    return color;
}

public int getX() {
    return x;
}

public int getY() {
    return y;
}
public void move(int dx, int dy) {
    x += dx;
    y += dy;
}

public void setColor(Color color) {
    this.color = color;
}
}
---------------------------------------------------------------------------

package NervousShapes;

import java.awt.*;

public class Circle extends Shape {
// Instance variables
private int diameter;

// Constructor
public Circle(int x, int y, Color color, int diameter) {
    super(x, y, color);
    this.diameter = diameter;
}
// Instance methods
public void draw(Graphics g) {
    g.setColor(getColor());
    g.fillOval(getX(), getY(), diameter, diameter);
}

public int getHeight() {
    return diameter;
}

public int getWidth() {
    return diameter;
}

Answer 1

import java.awt.*;
import java.awt.event.*;
import java.awt.image.*;
import javax.imageio.*;
import javax.swing.*;
import javax.swing.event.*;

public class DrawingPanel implements ActionListener {
    public static final int DELAY = 50; // delay between repaints in millis

    private static final String DUMP_IMAGE_PROPERTY_NAME = "drawingpanel.save";
    private static String TARGET_IMAGE_FILE_NAME = null;
    private static final boolean PRETTY = true; // true to anti-alias
    private static boolean DUMP_IMAGE = true; // true to write DrawingPanel to file

    private int width, height;    // dimensions of window frame
    private JFrame frame;         // overall window frame
    private JPanel panel;         // overall drawing surface
    private BufferedImage image; // remembers drawing commands
    private Graphics2D g2;        // graphics context for painting
    private JLabel statusBar;     // status bar showing mouse position
    private long createTime;

import java.awt.*;

public class Rectangle extends Shape {
// Instance variables
private int width;
private int height;

// Constructor
public Rectangle(int x, int y, Color color,
                   int width, int height) {
    super(x, y, color);
    this.width = width;
    this.height = height;
}
// Instance methods
public void draw(Graphics g) {
    g.setColor(getColor());
    g.fillRect(getX(), getY(), width, height);
}

public int getHeight() {
    return height;
}

public int getWidth() {
    return width;
}
}
----------------------------------------------------------------------

package NervousShapes;

import java.awt.*;

public abstract class Shape {
// Instance variables
private int x;
private int y;
private Color color;

// Constructor
protected Shape(int x, int y, Color color) {
    this.x = x;
    this.y = y;
    this.color = color;
}
// Abstract methods
public abstract void draw(Graphics g);
public abstract int getHeight();
public abstract int getWidth();

// Other instance methods
public Color getColor() {
    return color;
}

public int getX() {
    return x;
}

public int getY() {
    return y;
}
public void move(int dx, int dy) {
    x += dx;
    y += dy;
}

public void setColor(Color color) {
    this.color = color;
}
}
---------------------------------------------------------------------------

package NervousShapes;

import java.awt.*;

public class Circle extends Shape {
// Instance variables
private int diameter;

// Constructor
public Circle(int x, int y, Color color, int diameter) {
    super(x, y, color);
    this.diameter = diameter;
}
// Instance methods
public void draw(Graphics g) {
    g.setColor(getColor());
    g.fillOval(getX(), getY(), diameter, diameter);
}

public int getHeight() {
    return diameter;
}

public int getWidth() {
    return diameter;
}