/* Filled Julia set    Evgeny Demidov,  1 October 2000
     URL: www.ipm.sci-nnov.ru/~demidov/eng/java_e.htm */
  
  import java.awt.*;
  import java.awt.image.*;
  import java.awt.event.*;
  import java.util.StringTokenizer;
  
  public class applet-math-fractal-fjulia extends java.applet.Applet implements MouseListener {
  double maxIZI2=4., Ymid=.0, Xmid=-.5, DelX=3.,  paramC,paramD, eps, Rorb,Iorb;
  int MaxIt = 256,  maxColor = 96, w, h, pixArr[];
  Image img;             IndexColorModel RainbowColor;
  long generTime;        boolean   showXY = true;
  FormulaFJ formBT;        TextField tfXY;
  
  public void init() {
    String s=getParameter("XYmidDelCD"); if (s != null) {
      StringTokenizer st = new StringTokenizer(s);
      Xmid = Double.valueOf(st.nextToken()).doubleValue();
      Ymid = Double.valueOf(st.nextToken()).doubleValue();
      DelX = Double.valueOf(st.nextToken()).doubleValue();
      paramC = Double.valueOf(st.nextToken()).doubleValue();
      paramD = Double.valueOf(st.nextToken()).doubleValue();}
    s=getParameter("MaxIt"); if (s != null) MaxIt=Integer.parseInt(s);
    s=getParameter("MaxColor"); if (s != null) maxColor=Integer.parseInt(s);
    int M=maxColor/3,  M2=2*M;  maxColor = 3*M;     // maxColor is 3*int
    long M4 = (long)M*M*M*M;
    byte rColor[] = new byte[maxColor+1], bColor[] = new byte[maxColor+1],
         gColor[] = new byte[maxColor+1];
    for (int i = 1; i < M2; i++){                   // set Color Map
      long dum = M - i;  dum *=dum;  dum *=dum;
      gColor[i] =  bColor[(i+M) % maxColor] = rColor[(i+M2) % maxColor] =
          (byte)(255 - (255*dum)/M4);}
    RainbowColor = new IndexColorModel( 8, maxColor+1, rColor,gColor,bColor);
    w = getSize().width;   h = getSize().height;
    s=getParameter("showXY");
    if ( (s != null) && (s.equalsIgnoreCase("N")) ) showXY = true;
    else{
      setLayout(new BorderLayout());
      if (Ymid < 0.) s = ""+Xmid+" "+Ymid+"*i; "+(float)DelX;
         else s = ""+Xmid+" +"+Ymid+"*i; "+(float)DelX;
      tfXY = new TextField( s );
      add("South",  tfXY);
      h -= tfXY.getPreferredSize().height;}
    pixArr = new int[w*(h+2)];
    s=getParameter("Formula");
    if (s != null)
      try{  formBT = (FormulaFJ)Class.forName( s ).newInstance();
      }catch(Exception e){}
    else    formBT = new FilledJulZ2();
    formBT.set(3*MaxIt, maxColor, maxIZI2, 0, 10., 10.);
    formBT.iterate(0., 0., paramC, paramD);
    Rorb = formBT.lastR;    Iorb = formBT.lastI;
    formBT.set(MaxIt, maxColor, maxIZI2, 1e-6, Rorb, Iorb);
    formBT.iterate(0., 0., paramC, paramD);
    double tr = Rorb - formBT.lastR,   ti = Iorb - formBT.lastI;
    eps =tr*tr + ti*ti;
    formBT.set(MaxIt, maxColor, maxIZI2, eps, Rorb, Iorb);
    generTime = System.currentTimeMillis();
    Direct(Xmid, Ymid, DelX/w, formBT, paramC, paramD );
    img = createImage(new MemoryImageSource(w, h, RainbowColor, pixArr, w, w));
    generTime = System.currentTimeMillis()-generTime;
    addMouseListener(this);
  }
  
  public void destroy() {  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) {
    Xmid = Xmid+(e.getX()-w/2)*DelX/w;
    Ymid = Ymid-(e.getY()-h/2)*DelX/w;
    if ( e.isControlDown() ) {
      if ( e.isShiftDown() )  DelX *=4.;  else  DelX *=2.;}
    else {
      if ( e.isShiftDown() )  DelX /=4.;  else  DelX /=2.;}
    generTime = System.currentTimeMillis();
    Direct(Xmid, Ymid, DelX/w, formBT, paramC, paramD);
    img.flush();
    img = createImage(new MemoryImageSource(w, h, RainbowColor, pixArr, w, w));
    generTime = System.currentTimeMillis()-generTime;
    if (showXY) {
      if (Ymid < 0.) tfXY.setText( ""+Xmid+" "+Ymid+"*i; "+(float)DelX);
         else  tfXY.setText( ""+Xmid+" +"+Ymid+"*i; "+(float)DelX);};
    repaint();
  }
  
  public void paint(Graphics g) {
    g.drawImage(img, 0, 0, this);
    drawLabel(g);
    showStatus( "Time=" + generTime + " msec");
  }
  
  public void drawLabel(Graphics gra) {
   double  R=0.,I=0., StZ=DelX/w;
   gra.setColor(Color.white);
   int ix,iy;
   String s=getParameter("sqrRID"); if (s != null) {
     StringTokenizer st = new StringTokenizer(s);
     double sqrRmid = Double.valueOf(st.nextToken()).doubleValue(),
     sqrImid = Double.valueOf(st.nextToken()).doubleValue();
     int sqr = (int)(Double.valueOf(st.nextToken()).doubleValue()/StZ);
     ix = (w - sqr)/2 + (int)((sqrRmid-Xmid)/StZ);
     iy = (h - sqr)/2 + (int)((Ymid - sqrImid) /StZ);
     gra.drawRect(ix,iy, sqr,sqr);}
   gra.setFont(
     new Font( gra.getFont().getName(), Font.BOLD, 15 ) );
   int maxLabel=0, w2 = w/2, h2 = h/2;
   double dw2 = w2, dh2 = h2;
   while (true) {
     s=getParameter("lb"+maxLabel);
     if (s == null) break;
     StringTokenizer st = new StringTokenizer(s);
     double x=(Double.valueOf(st.nextToken()).doubleValue()-Xmid)/StZ,
     y=(Ymid-Double.valueOf(st.nextToken()).doubleValue())/StZ;
     if ( (Math.abs(x)<dw2)&&(Math.abs(y)<dh2) ){
       ix = w2+(int)x;  iy = h2+(int)y;
       gra.drawString(st.nextToken(), ix,iy);}
     maxLabel++; }
  }
  
  public void Direct( double Xmid, double Ymid, double Step,
    FormulaFJ form, double parC, double parD){
    double X,Y;
    int pix=w, ix,iy;
    for (iy=0, Y=Ymid+Step*h/2; iy < h; iy++, Y-=Step) {
     for (ix=0, X=Xmid-Step*(w/2-1); ix < w; ix++, X+=Step, pix++) {
        pixArr[pix] =form.iterate(X, Y, parC, parD);
     }
    }
  }
  
  }
  
  abstract class FormulaFJ{
    int MaxIt, maxColor;
    double maxIZI2, eps,  Rorb, Iorb,  lastR, lastI;
    void set(int mIt, int mCol, double mIZI2, double e, double Ro, double Io) {
      MaxIt = mIt;   maxColor = mCol;  maxIZI2 = mIZI2;  eps = e;
      Rorb = Ro;    Iorb = Io;
    }
    abstract int iterate(double x, double y, double paramC, double paramD);
  }
  
  class FilledJulZ2 extends FormulaFJ {
    int iterate(double re, double im, double Cr, double Ci) {
      double I=im, R=re,  I2=I*I, R2=R*R;   int n=0;
      do  {  I=(R+R)*I+Ci;  R=R2-I2+Cr;  R2=R*R;  I2=I*I;  n++;
        if (R2+I2 > maxIZI2) return n % maxColor;
      } while (((R-Rorb)*(R-Rorb)+(I-Iorb)*(I-Iorb) > eps) && (n < MaxIt) );
      lastR = R;  lastI = I;
      if (n == MaxIt) return maxColor;  else return n % maxColor;
    }
  }
  
  class FilledJulZ2black extends FormulaFJ {
    int iterate(double re, double im, double Cr, double Ci) {
      double I=im, R=re,  I2=I*I, R2=R*R;   int n=0;
      do  {  I=(R+R)*I+Ci;  R=R2-I2+Cr;  R2=R*R;  I2=I*I;  n++;
        if (R2+I2 > maxIZI2) return maxColor;
      } while (((R-Rorb)*(R-Rorb)+(I-Iorb)*(I-Iorb) > eps) && (n < MaxIt) );
      lastR = R;  lastI = I;
      if (n == MaxIt) return maxColor;  else return n % maxColor;
    }
  }
  
  class HenonInt extends FormulaFJ{
   int iterate(double Xo, double Yo, double a, double b){
      double X=a + Xo*Xo + b*Yo, X2=X*X, X1, Y=Xo;   int n=0;
      do{
        X1 = a + X2 + b*Y;  Y = X;
        X = X1;  X2 = X*X;   n++;
        if (X2 > 1000.) return n % maxColor;
      } while (((X-Rorb)*(X-Rorb)+(Y-Iorb)*(Y-Iorb) > eps) && (n < MaxIt) );
      lastR = X;  lastI = Y;
      if (n == MaxIt) return maxColor;  else return n % maxColor;
   }
  }