import java.awt.*;
import java.awt.image.*;
import java.awt.geom.*;
import javax.swing.*;
import java.util.Random;

public class Eigen extends JComponent implements Runnable
{

  int imageWidth, imageHeight;

  double xLowerLeft, yLowerLeft, xUpperRight, yUpperRight;
  double pixelWidth, pixelHeight, invPixelWidth, invPixelHeight;
  double TwoPi = 2*Math.PI;
  
  double[][] linImage = new double[2000][2];

  Random randNumGen = new Random(5);
  
  BufferedImage bufImage;
  Graphics2D bufImageGraphic;

  public Eigen(int w, int h, double xLL, double yLL, double xUR,
                 double yUR) 
  {
    imageWidth = w; imageHeight = h;
    xLowerLeft =  xLL; yLowerLeft =  yLL;
    xUpperRight = xUR; yUpperRight = yUR;
  	
    pixelWidth  = (xUR - xLL)/((double)w); 
    invPixelWidth  = ((double)w)/(xUR - xLL);
    pixelHeight = (yUR - yLL)/((double)h); 
    invPixelHeight = ((double)h)/(yUR - yLL);
  	
    //System.out.println(imageWidth + "     " + imageHeight);
    //System.out.println(pixelWidth + "     " + pixelHeight);

    for (int i = 0; i < 2000; ++i)
    {
      linImage[i][0] = Math.cos((i/2000.0)*TwoPi);
      linImage[i][1] = Math.sin((i/2000.0)*TwoPi);
    }

    bufImage = new BufferedImage(w, h, BufferedImage.TYPE_INT_RGB);
    bufImageGraphic = bufImage.createGraphics( );
    bufImageGraphic.setPaint(Color.white);
    //bufImageGraphic.setPaint(Color.black);
    bufImageGraphic.fillRect(0, 0, w, h);

    AffineTransform at = new AffineTransform(invPixelWidth, 
                                             0, 0, -invPixelHeight,
                                             -invPixelWidth*xLL, 
                                             invPixelHeight*yUR      
                                            );
    bufImageGraphic.setTransform(at);

    Thread t = new Thread(this);
    t.start(  );
  }
 
  public void Transform( )
  {
    int k = 0;
    double Max = 0;
    for (int i = 0; i < 2000; ++i)
    {
      double temp = linImage[i][0];
      linImage[i][0] = linImage[i][1];
      linImage[i][1] = temp + linImage[i][1];
    }
    for (int i = 0; i < 2000; ++i)
    {
      double normSq = 
        linImage[i][0]*linImage[i][0] + linImage[i][1]*linImage[i][1];
      if (Max < normSq)
      {
        Max = normSq; k = i;
      }
    }
    Max = Math.sqrt(Max);
    for (int i = 0; i < 2000; ++i)
    {
      linImage[i][0] = linImage[i][0]/Max;
      linImage[i][1] = linImage[i][1]/Max;
    }
    System.out.println(linImage[k][0] + "  " + linImage[k][1]);
    System.out.println(Max);
  }

  public void timeStep(int i)
  {
    Rectangle2D p = 
      new Rectangle2D.Double(linImage[i][0], linImage[i][1], 
                             pixelWidth/1.0, pixelHeight/1.0); 
    Color col = 
      new Color((float)(i/2000.0), 0, (float)(1 - (i/2000.0)));
    bufImageGraphic.setPaint(col);
    bufImageGraphic.fill(p);
  }

  public void run( ) 
  {
    Transform( );
    try 
    { 
      for (int i = 0; i < 2000; ++i)
      { //Loopbody:
        timeStep(i); 
        repaint( );
        Thread.sleep(0);
      }
    }
    catch (InterruptedException ie) {} 
  }

  public void paint(Graphics g) 
  {
    Graphics2D g2 = (Graphics2D)g;
    g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
                        RenderingHints.VALUE_ANTIALIAS_OFF);
    //g2.setPaint(Color.blue);
    //g2.drawImage(image, imageX, imageY, this);
    g2.drawImage(bufImage, 0, 0, this);
  }

  public static void main(String[] args) 
  {
    JFrame frame = new JFrame("Eigen");
    frame.setBackground(Color.white);
    Eigen plot = new Eigen(700, 700, -1.2, -1.2, 1.2, 1.2);
    frame.getContentPane( ).add(plot);
    frame.setSize(700, 700);
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.setVisible(true);
  }

}