// A simple interface for drawing persistent images. // Final version with events, pp. 773-775, Building Java Programs, Reges/Stepp. import java.awt.*; import java.awt.event.*; import java.awt.image.*; import javax.swing.*; import javax.swing.event.*; public class DrawingPanel extends MouseInputAdapter implements ActionListener {     private JFrame frame;         // overall window frame     private JPanel panel;         // drawing surface     private JLabel statusBar;     // status bar     private Graphics g;         // drawing pen                                 // constructs a drawing panel of given size     public DrawingPanel(int width, int height) {                                 // set up the empty image onto which we will draw         BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_ARGB);         g = image.getGraphics();         g.setColor(Color.BLACK);                                 // enclose the image in a label inside a panel         JLabel label = new JLabel();         label.setIcon(new ImageIcon(image));         panel = new JPanel(new FlowLayout());         panel.setBackground(Color.WHITE);         panel.setPreferredSize(new Dimension(width, height));         panel.add(label);                                 // the status bar that shows the mouse position         statusBar = new JLabel(" ");                                      // attach listener to observe mouse movement         panel.addMouseListener(this);         panel.addMouseMotionListener(this);                                      // set up the JFrame         frame = new JFrame( "Drawing Panel");         frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);         frame.setResizable(false);         frame.setLayout(new BorderLayout());         frame.add(panel, BorderLayout.CENTER);         frame.add(statusBar, BorderLayout.SOUTH);         frame.pack();         frame.setVisible(true);                                          // start a repaint timer to refresh the screen         Timer timer = new Timer(250, this);         timer.start();     }                                      // obtains the Graphics object to draw on the panel     public Graphics getGraphics() {         return g;     }                                      // sets the background color of the drawing panel     public void setBackground(Color c) {         panel.setBackground(c);     }                                       // shows or hides the drawing panel on the screen     public void setVisible(boolean visible) {         frame.setVisible(visible);     }                                      // used for timer that repeatedly repaints screen     public void actionPerformed(ActionEvent e) {         panel.repaint();     }                                      // draws status bar text when mouse moves     public void mouseMoved(MouseEvent e) {         statusBar.setText("(" + e.getX() + ", " + e.getY() + ")");     } }

			DrawLine2

			DrawShapes2

			DrawColorGradient

			Read pp. 174-197.

			Do Programming Project 1, p. 203.