// Henon mapping,  Evgeny Demidov,  27 June 2007

import java.awt.*;
import java.awt.image.*;
import java.awt.event.*;
import java.util.StringTokenizer;

public class @file extends java.applet.Applet implements MouseListener,
  KeyListener, ActionListener, MouseMotionListener{
double Yc=0, Xc=0, dx=35, dy=dx, Xm, Ym, Rm=.3, R=.5, a=-8, b=1;
int maxColor=5, N=2, w, h, w2, h2, ix, ixo, iy, iyo, ir, ir2,
  pixArr[],  px[],py[], pxo[],pyo[];
Image img;             IndexColorModel RainbowColor;
Label     lbA, lbB, lbR, lbN;
TextField tfXY, tfA, tfB, tfR, tfN;
Button    btPl, btMn;
boolean   bXOR=false, bR2=false;

public void init() {
  String s=getParameter("XYmidDelCD"); if (s != null) {
    StringTokenizer st = new StringTokenizer(s);
    Xc = Double.valueOf(st.nextToken()).doubleValue();
    Yc = Double.valueOf(st.nextToken()).doubleValue();
    dx = Double.valueOf(st.nextToken()).doubleValue();
    dy = Double.valueOf(st.nextToken()).doubleValue();}
  Xm = Xc;  Ym = Yc;
  s=getParameter("ab"); if (s != null) {
    StringTokenizer st = new StringTokenizer(s);
    a = Double.valueOf(st.nextToken()).doubleValue();
    b = Double.valueOf(st.nextToken()).doubleValue();}
  s=getParameter("R2"); if (s != null) bR2 = true;
  s=getParameter("R"); if (s != null) R = Double.valueOf(s).doubleValue();
  s=getParameter("Rm"); if (s != null) Rm = Double.valueOf(s).doubleValue();
  s=getParameter("N"); if (s != null) N=Integer.parseInt(s);
  if (N < 0) N = 0;
  s=getParameter("MaxColor"); if (s != null) maxColor=Integer.parseInt(s);
  byte rColor[] = new byte[maxColor], bColor[] = new byte[maxColor],
       gColor[] = new byte[maxColor];
  rColor[0] = gColor[0] = bColor[0] = (byte)255;
  gColor[1] = (byte)255;
  bColor[2] = (byte)255;
  rColor[3] = (byte)255;
  bColor[4] = gColor[4] = rColor[4] = 0;
  RainbowColor = new IndexColorModel( 8, maxColor, rColor,gColor,bColor);
  w = getSize().width;   h = getSize().height;
  w2 = w/2;  h2 = h/2;
  pixArr = new int[w*h];
  this.setLayout( new FlowLayout(FlowLayout.LEFT, 0, 0) );
  tfXY = new TextField( ""+(float)Xc+" "+(float)Yc+"; "+(float)dx+
    " "+(float)dy, 20);   add(tfXY);
  lbA = new Label("A", Label.RIGHT); add(lbA);
  tfA = new TextField( "" + a, 2);   add(tfA);
  tfA.addKeyListener(this);
  lbB = new Label("B", Label.RIGHT); add(lbB);
  tfB = new TextField( "" + b, 2);   add(tfB);
  tfB.addKeyListener(this);
  lbR = new Label("R", Label.RIGHT); add(lbR);
  tfR = new TextField( "" + R, 2);   add(tfR);
  tfR.addKeyListener(this);
  lbN = new Label("N", Label.RIGHT); add(lbN);
  tfN = new TextField( "" + N, 1);   add(tfN);
  tfN.addKeyListener(this);
  btPl = new Button("+"); btPl.addActionListener(this); add(btPl);
  btMn = new Button("-"); btMn.addActionListener(this); add(btMn);
  px = new int[9];  pxo = new int[9];  py = new int[9];  pyo = new int[9];
  addMouseMotionListener(this);
  addMouseListener(this);
  Draw();
}

public void destroy() {
  removeMouseMotionListener(this);
  removeMouseListener(this); }
public void mouseClicked(MouseEvent e) {}      //1.1 event handling
public void mousePressed(MouseEvent e) {}
public void mouseEntered(MouseEvent e) {}
public void mouseExited(MouseEvent  e) {}

public void mouseReleased(MouseEvent e) {
  if (e.isControlDown()||e.isAltDown()){
    Xc = Xc+(e.getX()-w2)*dx/w;
    Yc = Yc-(e.getY()-h2)*dx/w;}
  else return;
  if (e.isControlDown()){
    dy *= 2.; if (!e.isShiftDown()) dx *= 2.;}
  if (e.isAltDown()) {
    dy /= 2.; if (!e.isShiftDown()) dx /= 2.;}
  tfXY.setText( ""+(float)Xc+" "+(float)Yc+"; "+(float)dx+" "+(float)dy);
  Draw();
  repaint();
}
public void mouseMoved(MouseEvent e){}  //1.1 event handling

public void mouseDragged(MouseEvent e) {
  if (e.isControlDown()||e.isAltDown()) return;
  ix = e.getX(); iy = e.getY();
  Xm = Xc+(ix-w2)*dx/w;  Ym = Yc-(iy-h2)*dx/w;
  Polygon();
  bXOR = true;
  repaint();
}

public void actionPerformed(ActionEvent e){
  if ( e.getActionCommand().equals("+") ) N++;  else N--;
  if (N < 0) N = 0;
  tfN.setText(""+N);
  Draw();
  repaint();
}
public void keyTyped(KeyEvent e) {}
public void keyPressed(KeyEvent e) {}
public void keyReleased(KeyEvent e) {
  final int keyEnter = 10;
  if (e.getKeyCode() == keyEnter) {
    try{
      a = Double.valueOf(tfA.getText()).doubleValue();
      b = Double.valueOf(tfB.getText()).doubleValue();
      R = Double.valueOf(tfR.getText()).doubleValue();
      N = Integer.parseInt(tfN.getText());
      if (N < 0) { N = 0; tfN.setText(""+N); }
      Draw();
      repaint();
    }catch ( NumberFormatException ne) {}
  }
  e.consume();
}

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

public void paint(Graphics g) {
  if(!bXOR){
   g.drawImage(img, 0, 0, this);
   g.setColor(Color.black);
   drawLabel(g);
   g.setColor(Color.white);
   g.setXORMode(Color.black);
   double X, b1 = (1-b)*.5, d=b1*b1-a;
   if (d > 0){
     X = b1 - Math.sqrt(d);
     int ix = w2 + (int)((X - Xc)*w/dx);
     int iy = h2 - (int)((X - Yc)*h/dy);
     g.drawLine(ix-5,iy, ix+5,iy); g.drawLine(ix,iy-5, ix,iy+5);
     X = b1 + Math.sqrt(d);
     ix = w2 + (int)((X - Xc)*w/dx);
     iy = h2 - (int)((X - Yc)*h/dy);
     g.drawLine(ix-5,iy, ix+5,iy); g.drawLine(ix,iy-5, ix,iy+5);}
   g.fillPolygon(px,py,9);
   g.drawRect(ix-ir,iy-ir,ir2,ir2);
   g.setPaintMode();}
  else{
   g.setXORMode(Color.black);
   g.setColor(Color.white);
   g.fillPolygon(pxo,pyo,9);
   g.drawRect(ixo-ir,iyo-ir,ir2,ir2);
   System.arraycopy(px,0,pxo,0,9);   System.arraycopy(py,0,pyo,0,9);
   ixo = ix; iyo = iy;
   g.fillPolygon(px,py,9);
   g.drawRect(ix-ir,iy-ir,ir2,ir2);
   g.setPaintMode();
   bXOR=false;}
}

public void Draw(){
  ix = ixo = w2 + (int)((Xm - Xc)*w/dx);
  iy = iyo = h2 - (int)((Ym - Yc)*h/dy);
  ir = (int)(Rm*w/dx);   ir2 = 2*ir;
  Polygon();
  System.arraycopy(px,0,pxo,0,9);
  System.arraycopy(py,0,pyo,0,9);

  for (int p = h*w; p > 0;) pixArr[--p] = 0;
  int pix, ix,iy;
  pix = 0;
  double X,Y, Xo,Yo, Xs, Xs1,  X1,Y1, t,  Rn,Rb;
  double b1 = (1-b)*.5, d=b1*b1-a;
  Xs = b1 + Math.sqrt(d);  Xs1 = b1 - Math.sqrt(d);
  Rn=R*R;   Rb=Rn*b*b*b*b;
  for (iy=0; iy < h; iy++) {
   Yo = Yc + (h2-iy)*dy/h;
   for (ix=0; ix < w; ix++){
    Xo = X = Xc + (ix-w2)*dx/w;  Y = Yo;
    for(int i=N; i>0; i--){
       t = a + X*X +b*Y;
       Y = X;   X = t; }
    if( (X-Xs)*(X-Xs)+(Y-Xs)*(Y-Xs) < Rb ) pixArr[pix] = 2;
    if( bR2 && ( (X-Xs1)*(X-Xs1)+(Y-Xs1)*(Y-Xs1) < Rb ) ) pixArr[pix] = 4;
    Y = Yo; X = Xo;
    for(int i=N; i>0; i--){
       t = (X-Y*Y-a)/b;
       X = Y;  Y = t; }
    if( (X-Xs)*(X-Xs)+(Y-Xs)*(Y-Xs) < Rn ) pixArr[pix] = 3;
    if(bR2 && ( (X-Xs1)*(X-Xs1)+(Y-Xs1)*(Y-Xs1) < Rn) ) pixArr[pix] = 1;
    pix++;}
  }
//System.out.println(""+Xc +"  "+Yc);
  img = createImage(new MemoryImageSource(w, h, RainbowColor, pixArr, 0, w));
}

public void drawLabel(Graphics gra) {
 gra.setColor(Color.black);
 int x,y;
 gra.setFont(
   new Font( gra.getFont().getName(), Font.BOLD, 15 ) );
 int maxLabel=0;
 while (true) {
   String s=getParameter("lb"+maxLabel);
   if (s == null) break;
   StringTokenizer st = new StringTokenizer(s);
   x=w2+(int)((Double.valueOf(st.nextToken()).doubleValue()-Xc)*w/dx);
   y=h2+(int)((Yc-Double.valueOf(st.nextToken()).doubleValue())*h/dy);
   gra.drawString(st.nextToken(), x,y);
   maxLabel++; }
}

public void Polygon(){
  double X=Xm-Rm, Y=Ym-Rm;  st(X, Y, 0);
  X=Xm;     st(X,Y,1);
  X=Xm+Rm;  st(X,Y,2);
  Y=Ym;     st(X,Y,3);
  Y=Ym+Rm;  st(X,Y,4);
  X=Xm;     st(X,Y,5);
  X=Xm-Rm;  st(X,Y,6);
  Y=Ym;     st(X,Y,7);
  px[8]=px[0]; py[8]=py[0];
}

public void st(double X, double Y, int k){
  px[k] = w2 + (int)((a + X*X +b*Y - Xc)*w/dx);
  py[k] = h2 - (int)((X - Yc)*h/dy);
}


}