import java.applet.Applet;
import java.awt.*;
import javax.swing.JFrame;
import java.awt.image.BufferedImage;
import java.util.Random;
public class SnowPic extends Applet implements Runnable{
Thread mainThread;
Image offScreen,gAlc[];
Random rand;
int stopFlag,snows,wind,threadSleep,snowSize;
int[] snowX,snowY;
long stopTime =0;
Dimension dim;
MediaTracker mt;
public SnowPic(){
}
int getParameter(String s1,int s2){
String s=null;
try{
s=getParameter(s1);
}catch(NullPointerException ex){
}
return(s !=null)?Integer.parseInt(s):s2;
}
int getParameter(String s1, int s2, int max, int min){
String s=null;
try{
s=getParameter(s1);
}catch(NullPointerException ex){
}
if(s!=null){
if((s2=Integer.parseInt(s))>max){
return max;
}else if (s2 return min;
}else{
return s2;
}
}else{
return s2;
}
}
String getParameter(String s1 , String s2){
String s=null;
try{
s=getParameter(s1);
}catch(NullPointerException ex){
}
return (s!=null)?s:s2;
}
public void init(){
rand =new Random();
dim =getSize();
snows =getParameter("snows", 100, 500,0);
snowSize =getParameter("snowSize",3,10,3);
threadSleep =getParameter("threadSleep",80,1000,10);
snowX = new int [snows];
snowY = new int [snows];
for( int i=0;i snowX[i]=rand.nextInt()%(dim.width/2)+dim.width/2;
snowY[i]=rand.nextInt()%(dim.height/2)+dim.height/2;
}
mt =new MediaTracker(this);
gAlc= new Image[1];
try{
gAlc[0]=getImage(getDocumentBase(), getParameter("graphic","test.gif"));
offScreen=createImage(dim.width, dim.height);
}catch(Exception ex){
gAlc[0]=new BufferedImage(dim.width, dim.height, BufferedImage.TYPE_INT_RGB );
offScreen=new BufferedImage(dim.width, dim.height, BufferedImage.TYPE_INT_RGB );
}
mt.addImage(gAlc[0],0);
try{
mt.waitForID(0);
}catch(InterruptedException ex) {
return;
}
stopFlag =0;
}
public void start(){
if (mainThread==null){
mainThread=new Thread(this);
mainThread.start();
}
}
public void stop(){
mainThread =null;
}
public void run(){
while(mainThread !=null){
try{
Thread.sleep(threadSleep);
}catch(InterruptedException ex) {return;}
repaint();
}
}
public void drawBackSnow(Graphics g){
g.setColor(Color.white);
for(int i=0;i g.fillOval(snowX[i],snowY[i],snowSize,snowSize);
snowX[i]+=rand.nextInt()%2+wind;
snowY[i]+=(rand.nextInt()%6+5)/5+1;
if(snowX[i]>=dim.width) snowX[i]=0;
if(snowX[i]<0) snowX[i]=dim.width -1;
if(snowY[i]>=dim.height ||snowY[i]<0){
snowX[i] =Math.abs(rand.nextInt()%dim.width);
snowY[i] =0;
}
}
wind =rand.nextInt()%5 -2;
}
public void paint(Graphics g){
offScreen.getGraphics().setColor(Color.black);
offScreen.getGraphics().fillRect(0,0,dim.width,dim.height);
offScreen.getGraphics().drawImage(gAlc[0],0,0,this);
drawBackSnow(offScreen.getGraphics());
g.drawImage(offScreen,0,0,null);
}
public void update(Graphics g){
paint(g);
}
public static void main(String args[]){
SnowPic snow=new SnowPic();
snow.setBounds(0,0, 500, 500);
snow.init();
JFrame jf=new JFrame("SnowPic");
jf.setSize(500, 500);
jf.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
jf.add(snow);
jf.setVisible(true);
snow.start();
}
}
请参考
