JAVA-MANI.BLOGSPOT.COM

Let's have a little fun with random letters! First, we create a String object alphabet, containing all 26 letters of the alphabet. Then we draw a random number between 0 and 25 and use it as an argument in the String method substring. We pass two integer arguments for the first and the last character of the new substring, so we get a random character. To make it fun to watch, we also randomize the color, size and position of the letter on the screen. After some time, we redraw the background black.

//Sourcecode

import java.awt.*;
import java.applet.*;

public class Project37 extends Applet implements Runnable
{
   Thread runner;
   Image Buffer;
   Graphics gBuffer;
   String alphabet="ABCDEFGHIJKLMNOPQRSTUVWXYZ";
   int ticker;

   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)
       {
           try {runner.sleep(50);}
           catch (Exception e) { }

           repaint();
       }
   }

   public void drawStuff()
   {
       //repaint background after 20 seconds
       if(ticker==0)
       {
           gBuffer.setColor(Color.black);
           gBuffer.fillRect(0,0,size().width,size().height);
       }

       ticker++;
       if(ticker>400)
           ticker=0;

       //random font size 10..50
       int fontSize=(int)(Math.random()*40)+10;

       //random font color
       int red=(int)(Math.random()*255);
       int green=(int)(Math.random()*255);
       int blue=(int)(Math.random()*255);
       gBuffer.setColor(new Color(red, green, blue));

       //random coordinates within the applet bounderies
       int x=(int)(Math.random()*size().width);
       int y=(int)(Math.random()*size().height);

       //random substring from the alphabet string (one out of 26 characters)
       int character=(int)(Math.random()*26);
       String s=alphabet.substring(character, character+1);

       gBuffer.setFont(new Font("TimesRoman", Font.PLAIN,  fontSize));
       gBuffer.drawString(s,x,y);
   }

   public void update(Graphics g)
   {
       paint(g);
   }

   public void paint(Graphics g)
   {
       drawStuff();
       g.drawImage (Buffer,0,0, this);
   }
}