import java.awt.*; /** * Example3Applet * * This is a template applet for animation. * It illustrates how to use a graphics context * to draw to the screen. * * @author Arthur van Hoff */ public class Example3Applet extends java.applet.Applet implements Runnable { int frame; int delay; Thread animator; /** * Initialize the applet and compute the delay between frames. */ public void init() { String str = getParameter("fps"); int fps = (str != null) ? Integer.parseInt(str) : 10; delay = (fps > 0) ? (1000 / fps) : 100; } /** * This method is called when the applet becomes visible on * the screen. Create a thread and start it. */ public void start() { animator = new Thread(this); animator.start(); } /** * This method is called by the thread that was created in * the start method. It does the main animation. */ public void run() { // Remember the starting time long tm = System.currentTimeMillis(); while (Thread.currentThread() == animator) { // Display the next frame of animation. repaint(); // Delay depending on how far we are behind. try { tm += delay; Thread.sleep(Math.max(0, tm - System.currentTimeMillis())); } catch (InterruptedException e) { break; } // Advance the frame frame++; } } /** * This method is called when the applet is no longer * visible. Set the animator variable to null so that the * thread will exit before displaying the next frame. */ public void stop() { animator = null; } /** * Paint a frame of animation. */ public void paint(Graphics g) { g.setColor(Color.black); g.drawString("Frame " + frame, 0, 30); } }