txtcolor.java

有关java的源程序,为讲授java程序设计课程使用

import java.awt.*;
import java.applet.*;
import java.util.Date;
import java.net.*;
import java.io.*;
public class TxtColor extends java.applet.Applet implements Runnable
{
	Thread textThread=null;
   	int Red, Green,Blue;
	int stringX, stringY;
    int FontSize=16;
	String Text="Hello,How Are You !";
	Dimension rectSize;
    FontMetrics fm;
	public void init()
	{
		Red=255;
		Green=255;
		Blue=255;
//		setFont(new Font("Helvetica",Font.BOLD,16));
		setFont(new Font("Helvetica",Font.BOLD,FontSize));
		fm=getFontMetrics(getFont());
		rectSize=size();			
		stringY=rectSize.height;
		stringX=0;
		setBackground(Color.white);	
	}
	public void start()
	{			
		if (textThread==null)
		{
			textThread=new Thread(this,"text");
			textThread.start();
		}
	}

	public void run()
	{
		while (Thread.currentThread()==textThread)
		//因只有一个线程，也可while (True)
		{
			repaint();
//重绘一次，停一会
			try {
				        textThread.sleep(100);
				}
			catch(InterruptedException e)
				{
				}
		}
	}
	public void update(Graphics  g)
	//消除闪烁，清除指定范围
	{
		g.clipRect(stringX,stringY-fm.getAscent(),rectSize.width,fm.getHeight());
		g.clearRect(stringX,stringY-fm.getAscent(),rectSize.width,fm.getHeight());
		paint(g);
	}
	public void paint(Graphics g)
	{
		if (stringY<=0)
			{
			   stringY=rectSize.height;
			  // stringY++;
			}
		stringY--;
//*****************开始颜色变换************
		Color textColor=new Color(Red,Green,Blue);
		setFont(new Font("Helvetica",Font.BOLD,FontSize));
	    FontSize++;
        if(FontSize>72);
		  {FontSize=16;
		  }
		g.setColor(textColor);
        g.drawString(Text,stringX,stringY);
     
		if (stringY<rectSize.height/2)/*如在上半屏幕*/
		{
                        if(Green>=255)
                             {
                                 Green=255;
                                 Red=255;
                                 Blue=255;
                             }
			else
                             {
                                 Green=Green+3;
                                 Red=Red+3;
                                 Blue=Blue+3;
                             }
		}
		else
		{
			if(Green<=0)
                                {
                                        Green=0;
                                        Red=0;
                                        Blue=0;
                                }
			else
                                {
                                        Green=Green-3;
                                        Red=Red-3;
                                        Blue=Blue-3;
                                }
		}
//******************颜色变换End*******
	}


	
	public void stop()
	{
		textThread=null;
	}
	public boolean mouseEnter(Event event,int x,int y)
	{
		showStatus("Your Mouse Is Enter Applet Panel !");
		return true;
	}
	
}