// File Screensaver.java
// 
// Author: Benjamin Lewis
// Date:   March 20 1999
//
// This program simulates a screensaver. It draws 100 random lines in the
// applet window, one at a time, and then clears the window and starts over.
//
// Bugs: infinite loop in paint method. Multi-threading could improve this.


import java.applet.Applet;
import java.awt.Color;
import java.awt.Graphics;

public class Screensaver extends Applet
{
  public static final int NUM_LINES = 100;
  public static final int PAUSE_MILLISEC = 80; // pause between lines
  public static final Color BACKGROUND_COLOR = Color.black;

  public void init()
  {
    setBackground(BACKGROUND_COLOR);
  }

  public void paint(Graphics g)
  {
    int x1, x2, y1, y2; // line coordinates
    Color lineColor;

    int height = getSize().height;
    int width  = getSize().width;

    while (true)
    {
      // clear screen
      g.clearRect(0, 0, width, height);
      
      for (int i=0; i<NUM_LINES; i++)
      {
	// draw a random line
	lineColor = new Color((float)Math.random(),
			      (float)Math.random(),
			      (float)Math.random());
	x1 = (int)(Math.random()*width);
	x2 = (int)(Math.random()*width);
	y1 = (int)(Math.random()*height);
	y2 = (int)(Math.random()*height);

	g.setColor(lineColor);
	g.drawLine(x1, y1, x2, y2);
	pause(PAUSE_MILLISEC);
      }
    }
  }
  
  private void pause(int millisec)
  {
    try
    {
      Thread.currentThread().sleep(millisec);
    }
    catch (InterruptedException e) {}
  }
}