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 triangles 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); }

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// 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

/////////////////////////////////////////////////////////// // 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 = 0 && newX + shapes[i].getWidth()

// 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()

// 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; }