//  Scott DeRuiter        3/6/2003
//  MoveCircle.java
//  Move a box around, implementing a MouseMotionListener in
//  a Swing Applet.
//	3/13/2013 Greenstein: changed applet to JFrame


import java.awt.*;
import java.awt.event.*;
import javax.swing.*;


public class MoveCircle implements MouseMotionListener 
{

   private int counter, sizeofarray;
   private int [] xpos;
   private int [] ypos;
   private boolean initialdraw;
   
   private JFrame frame;
   private MyPanel canvas;

   public MoveCircle ()    
	{
		sizeofarray = 100;
		counter = 100;
		xpos = new int [sizeofarray];
		ypos = new int [sizeofarray];
		for ( int i = 0; i < xpos.length; i++ )
			xpos[i] = ypos[i] = 0;
		initialdraw = true;
   }
   
   public static void main(String[] args) 
	{
   		MoveCircle mb = new MoveCircle();
   		mb.Run();
   }

   public void Run() 
	{
		// Create a frame to hold everything
		frame = new JFrame ("Move Circle");
		frame.setSize(500, 500);
		frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		//frame.setBackground(Color.black);	// only needed if frame is larger than panel
		
		// Define panel to draw on
		canvas = new MyPanel();		// create a panel to draw on
      	canvas.setBackground(Color.blue);
		canvas.addMouseMotionListener(this);	// connects the addMouseMotionListener to the panel window
		
		// Put frame together
		frame.getContentPane().add(canvas);	// puts panel on frame
		frame.setVisible(true);
   }
   
   
   class MyPanel extends JPanel 
	{

        public void paintComponent(Graphics g) 
		 {
      
        	super.paintComponent(g);

			if ( !initialdraw )   
			{
				for ( int i = xpos.length - 1; i >= 0; i-- )   
				{
					int value = (i + counter) % 5;
					switch ( value )   
					{
						case 0:   g.setColor ( Color.white );   break;
						case 1:   g.setColor ( Color.lightGray );   break;
						case 2:   g.setColor ( Color.gray );   break;
						case 3:   g.setColor ( Color.darkGray );   break;
						case 4:   g.setColor ( Color.black );   break;
					}
					if ( i == 0 )
						g.setColor ( Color.blue );
					g.fillOval ( xpos[i] - sizeofarray / 2 + i / 2, 
							ypos[i] - sizeofarray / 2 + i / 2, 
							sizeofarray - i, sizeofarray - i );
					if ( i == 0 )
						g.setColor ( Color.red );
					g.drawOval ( xpos[i] - sizeofarray / 2 + i / 2, 
							ypos[i] - sizeofarray / 2 + i / 2, 
							sizeofarray - i, sizeofarray - i );
				}
			}
			counter--;
			if ( counter == 0 )
				counter = 100;

			for ( int i = xpos.length - 1; i >= 1; i-- )   
			{
				xpos[i] = xpos[i-1];
				ypos[i] = ypos[i-1];
				ypos[i] -= 3;
			}
      	}
   }
		
   public void mouseMoved ( MouseEvent e )   
	{  
		xpos[0] = e.getX(); 
		ypos[0] = e.getY();
		if ( initialdraw )   
		{
			for ( int i = 0; i < xpos.length; i++ )   
			{
				xpos[i] = xpos[0];
				ypos[i] = ypos[0];
			}
			initialdraw = false;
		}
		canvas.repaint();
 	 }
    public void mouseDragged ( MouseEvent e )    {}
}