applet1.java

矩阵乘法的计算程序

import java.awt.*;
import java.applet.*;
import java.awt.event.*;
import java.util.*;

public class Applet1 extends Applet implements Runnable,MouseListener
{
	private Thread thread;
	private String str1,str2;
	private Font font1,font2;
	private int speed,lastX1,lastY1,directX1,directY1,lastX2,lastY2,directX2,directY2;
	
	public void init()
	{
		String param;
		addMouseListener(this);
		param=getParameter("speed");
		if(param==null)
			speed=50;
		else speed=Integer.valueOf(param).intValue();
		
		//font1=new Font("TimesRoman",Font.BOLD,30);
		font1=new Font("黑体",Font.BOLD,60);
		param=getParameter("str1");
		if (param==null)
			str1="Null";
		else str1=param;
		lastX1=(int)(Math.random()*(getSize().width-1));
		lastY1=(int)((getSize().height-font1.getSize()-1)*Math.random());
		directX1=3;
		directY1=3;
		
	}
	
	public void start(){
		this.setBackground(Color.white);
		if (thread==null){
			thread=new Thread(this);
			thread.start();
		}
	}
	
	public void paint(Graphics g){
		int x,y,space;
		StringTokenizer t;
		FontMetrics fm;
		
	
		g.setColor(Color.black);
		g.setFont(font1);
		fm=g.getFontMetrics();
		space=fm.stringWidth (" ");
		x=lastX1;
		y=lastY1;
		//以空格为分隔符依次从STR1中取字显示
		for(t=new StringTokenizer(str1);t.hasMoreTokens();){
			String word=t.nextToken();
			int w=fm.stringWidth(word)+space;
			if (x>getSize().width){
				x=x-getSize().width ;//到边界则回头
			}
			//产生一种随机色
			g.setColor(new Color((int)(Math.random()*256),(int)(Math.random()*256),(int)(Math.random()*256)));
			g.drawString(word,x,y);
			System.out.println(word);
			x+=w;
			y+=3;
		}
		if (Math.random()>0.99){
			directX1=-directX1;
		}
		//lastX1,lastY1为下一次显示字符串的起点位置
		//directX1,directY1为两次显示的间隔
		lastX1+=directX1;
		if (lastX1>=getSize().width){
			lastX1=0;
		}else if (lastX1<0){
			lastX1=getSize().width-1;
		}
		lastY1+=directY1;
		if (lastY1>=getSize().height){
			directY1=-3;
		}else if(lastY1<font1.getSize()){
			directY1=3;
		}
	}

	public void stop(){
		thread =null;
	}
	
	public void run(){
		while (thread !=null){
			repaint();
			try{
				thread.sleep(speed);
			}catch(InterruptedException e){}
		}
	}
	
	public void mouseClicked(MouseEvent e){}
	
	public void mouseEntered(MouseEvent e){
	}

	public void mouseExited(MouseEvent e){
	}
	
	public void mousePressed(MouseEvent e){
		if (thread==null){start();}
		else{ thread=null;}
	}
	public void mouseReleased(MouseEvent e){
	}
}