import java.applet.*;
import java.awt.*;
import java.awt.event.*;
import java.awt.image.*;

public class ImageApplet extends Applet implements ActionListener {
  
  int lastImage=2;
  Image im;
  int width = 400, height = 400;
  MemoryImageSource imSource;
  public void init() {
    setLayout(new BorderLayout());
    Button b = new Button("New image");
    b.addActionListener(this);
    add(b, "South");
  }
  public void start() {
    System.out.println("Busy...");
    imSource = new MemoryImageSource(width, height, getImageData(width, height), 0, width);
    im = createImage(imSource);
    System.out.println("made image "+im);
  }
  public void update(Graphics g) {
    paint(g);
  }
  public void actionPerformed(ActionEvent e) {
    System.out.println("Busy...");
    imSource = new MemoryImageSource(width, height, getImageData(width, height), 0, width);
    im = createImage(imSource);
    System.out.println("made image "+im);
    repaint();
  }
  public void paint(Graphics g) {
    g.drawImage(im, 0, 0, this);
    System.out.println("painted "+im);
  }
  
  public int[] toRedOrange(int data[]) {
    for(int i=0; i<data.length; i++) {
      data[i] = (data[i] << 8) | (255 << 16) | (255 << 24);  // red & orange
    }
    return data;
  }
  public int[] toBlueBlack(int data[]) {
    for(int i=0; i<data.length; i++) {
      data[i] = data[i] | (255 << 24); // black & blue
    }
    return data;
  }
  
  public int[] smooth(int [] data, int w, int h) {  // doesn't handle edges
    int[] newData = new int[data.length];
    int y, x, i;
    for(y=1; y<h-1; y++) {
      for(x=1; x<w-1; x++) {
        newData[x+w*y] = (data[x+w*y+w] + data[x+w*y-w] + data[x+w*y+1] + data[x+w*y-1] + data[x+w*y]) / 5;
      }
    }
    for(i=0; i<newData.length; i++) {
      newData[i] = newData[i] | (255 << 24); // black & blue
    }
    return newData;
  }
  
  public int[] getImageData(int w, int h) {
    int i = (lastImage++) % 7;
    int[] data = new int[0];
    if      (i==0) data = getGravityImageData(w, h, randInt(20));
    else if (i==1) data = getRandomImageData(w, h);
    else if (i==2) data = smooth(smooth(getRandomImageData(w, h), w, h), w, h);
    else if (i==3) data = getFeatherImageData(w, h);
    else if (i==4) data = smooth(smooth(getFeatherImageData(w, h), w, h), w, h);
    else if (i==5) data = getCheckerImageData(w, h);
    else if (i==6) data = smooth(smooth(getCheckerImageData(w, h), w, h), w, h);
    i = randInt(3);
    if (i==0) return toRedOrange(data);
    else return toBlueBlack(data);
  }
  public int[] getRandomImageData(int w, int h) {
    int i;
    int[] data = new int[w*h];
    for(i=0; i<data.length; i++) {
      data[i] = randInt(255);
    }
    return data;
  }
  public int[] getDoubleFeatherImageData(int w, int h) {
    int i;
    int[] data = new int[w*h], data1 = getFeatherImageData(w, h), data2 = getFeatherImageData(w, h);
    for(i=0; i<data.length; i++) {
      data[i] = ( data1[i] + data2[i%w + w*(h-i/w-1)] )/2;
    }
    return data;
  }
  public int[] getGravityImageData(int w, int h, int pCount) {
    int x, y, i, pDist, pWDist;
    Point3d[] points = new Point3d[pCount];
    for(i = 0; i<points.length; i++) {
      points[i] = new Point3d(randInt(w), randInt(h), randInt(255));
      System.out.println(points[i]);
    }
    int[] data = new int[w*h];
    for(y=0; y<h; y++) {
      for(x=0; x<w; x++) {
        pDist = 0;
        pWDist = 0;
        for(i=0; i<points.length; i++) {
          pDist  += 1000000 / (sqrDist(points[i].x - x, points[i].y - y)+1);
          pWDist += 1000000 / (sqrDist(points[i].x - x, points[i].y - y)+1) * points[i].z;
        }
        data[w*y+x] = pWDist/pDist;
      }
    }
    for(i=0; i<data.length; i++) {
      //data[i] = (data[i] << 8) | (255 << 16) | (255 << 24);  // red & orange
      data[i] = data[i] | (255 << 24); // black & blue
    }
    return data;
  }
  public int[] getFeatherImageData(int w, int h) {
    int x, y, i;
    int[] data = new int[w*h];
    data[0] = (int)(255*Math.random());
    for(x=1; x<w; x++) {
      data[x] = constrain( data[x-1] + dx() );
    }
    for(y=1; y<h; y++) {
      data[w*y] = constrain( data[w*y-w] + dx() );
    }
    for(y=1; y<h; y++) {
      for(x=1; x<w; x++) {
        data[w*y+x] = constrain( ( data[w*y+x-1] + data[w*y+x-w] )/2 + dx() );
      }
    }
    for(i=0; i<data.length; i++) {
      //data[i] = (data[i] << 8) | (255 << 16) | (255 << 24);  // red & orange
      data[i] = data[i] | (255 << 24); // black & blue
    }
    return data;
  }
  public int[] getCheckerImageData(int w, int h) {
    int x, y, i;
    int[] data = new int[w*h];
    data[0] = (int)(255*Math.random());
    for(x=1; x<w; x++) {
      data[x] = constrain( data[x-1] + dx() );
    }
    for(y=1; y<h; y++) {
      data[w*y] = constrain( data[w*y-w] + dx() );
    }
    for(y=1; y<h; y++) {
      for(x=1; x<w; x++) {
        data[w*y+x] = constrain( 2*( data[w*y+x-1] + data[w*y+x-w] - data[w*y+x-w-1] )/2 + dx() );
      }
    }
    for(i=0; i<data.length; i++) {
      //data[i] = (data[i] << 8) | (255 << 16) | (255 << 24);  // red & orange
      data[i] = data[i] | (255 << 24); // black & blue
    }
    return data;
  }
  
  public int dx() {
    return (int)(31*Math.random())-15;
  }
  public int constrain(int i) {
    if (i<0) return 0;
    else if (i>255) return 255;
    else return i;
  }
  public final static int randInt(int i) {
    return (int)(i*Math.random());
  }
  public final static int sqrDist(int x, int y) {
    return x*x+y*y;
  }
  
  class Point3d {
    public int x, y, z;
    public Point3d(int x, int y, int z) {
      this.x = x;
      this.y = y;
      this.z = z;
    }
    public String toString() {
      return "( "+x+" , "+y+" , "+z+" )";
    }
  }
  
}