The Java Boutique: Java Tutorial: Java by Example: Fonts and Graphics

import java.awt.*; import java.applet.*; //a flicker free animation! public class Project9 extends Applet implements Runnable { Thread runner; private Image Buffer; private Graphics gBuffer; int x, x1, x2=100; boolean moveRight=true; //Init is called first, do any initialisation here public void init() { //create graphics buffer, the size of the applet Buffer=createImage(size().width,size().height); gBuffer=Buffer.getGraphics(); } public void start() { if (runner == null) { runner = new Thread (this); runner.start(); } } public void stop() { if (runner != null) { runner.stop(); runner = null; } } public void run() { while(true) { //Thread sleeps for 15 milliseconds here try {runner.sleep(15);} catch (Exception e) { } //paint background blue gBuffer.setColor(Color.blue); gBuffer.fillRect(0,0,size().width,size().height); //move circle (slowly) right until it leaves applet //then let it appear again on the left side x++; if(x>size().width) x=-50; //move square left (with double speed) until it //leaves applet then let it reappear right side x1-=2; if(x1<-50) x1=size().width; //move the pink square right until it touches //border, then set flag "moveRight" to false if(moveRight==true) { if(x2<size().width-50) x2+=2; else moveRight=false; } //if flag "moveRight" is false, the pink square moves left //until it touches left border, then switch direction if(moveRight==false) { if(x2>0) x2-=2; else moveRight=true; } //the red circle gBuffer.setColor(Color.red); gBuffer.fillOval(x,30,50,50); //the green square gBuffer.setColor(Color.green); gBuffer.fillRect(x1,110,50,50); //the pink square gBuffer.setColor(Color.pink); gBuffer.fillRoundRect(x2,200,50,50,16,16); repaint(); } } //is needed to avoid erasing the background by Java public void update(Graphics g) { paint(g); } public void paint(Graphics g) { g.drawImage (Buffer,0,0, this); } }