//VelocityPlot1.java  draw a contour plot
// data input  nx ny     first line
//             x y z     many lines smallest x first
//                       followed by smallest y to largest

import java.awt.*;
import java.awt.event.*;
import java.io.*;
import java.*;

public class VelocityPlot1 extends Frame
{
  int ncont = 9; // contour lines zz normalized
  double dzz = 1.0/(ncont+1);  // first is dzz
    Color cont_color[] = {Color.black, Color.gray, Color.magenta,
                          Color.cyan, Color.blue, Color.green,
                          Color.yellow, Color.orange, Color.red};
  int width=800, height=800;
  double u1, u2, v1, v2; // velocity vector
  double xx[];
  double yy[];
  double zz[];
  double uu[];
  double vv[];
  int n_input;
  double xmin, xmax, ymin, ymax, zmin, zmax, umin, umax, vmin, vmax;
  int nxx=0, nyy=0, nxy=0; // index i*nxx+j
  int n=0;
  boolean connect;
  boolean debug = true;
  double Pi = 4.0*Math.atan(1.0);
  
  VelocityPlot1()
  {
    setTitle("VelocityPlot1");
    try{
      read_data();
    }
    catch(IOException exception)
    {
    }
    setSize(width,height);
    setBackground(Color.white);
    setForeground(Color.black);
    addWindowListener(new WindowAdapter()
    {
      public void windowClosing(WindowEvent e)
      {
        System.exit(0);
      }
    });
    setVisible(true);
    n=0;
    connect=false;
    this.addMouseListener (new mousePressHandler());
    repaint();

  } // end VelocityPlot1

  class mousePressHandler extends MouseAdapter
  {
    public void mousePressed (MouseEvent e)
    {
      int x, y, z, b;
      x = e.getX();
      y = e.getY();
      b = e.getButton();
      if(b==3 && n>0)
      {
        connect=true;
      }
      requestFocus();
      System.out.println("at x="+x+"   y="+y+"   b="+b); // debug print
      repaint();
    }
  } // end mousePressHandler

  int scalex(double a)
  {
      return (int)((double)(width-20)*a)+10;
  } // end scalex

  int scaley(double a)
  {
      return (int)((double)(height-60)*(a))+50;
  } // end scaley

  public void paint(Graphics g)
  {
    double x1, y1, x2, y2, z11, z12;
    double u1, v1, u2, v2, u3, v3, u4, v4;
    double a, a3, a4, du, dv;
    double z, nearz;
    boolean pt1, pt2;
    String fstring;

    g.setColor(Color.black);
    for(int i=0; i<nxy; i++) // data point location
    {
	g.drawOval(scalex(xx[i]), scaley(yy[i]), 2, 2);
    }

    for(int i=0; i<nxx; i++)
    {
      for(int j=0; j<nyy; j++)
      {
	  x1 = xx[i*nyy+j];
	  y1 = yy[i*nyy+j];
	  //
	  //  x1,y1 -u+ ->  x2,y1             
	  //    |
	  //   v+
	  //    |
	  //    v
	  //  x1,y2         x2,y2
          u1 = x1;
          v1 = y1;
          u2 = u1 + uu[i*nyy+j]/30.0;
          v2 = v1 + vv[i*nyy+j]/30.0;
          g.drawLine(scalex(u1), scaley(v1),
                     scalex(u2), scaley(v2));
          a = Math.atan2(u2-u1,v2-v1);
          a3 = a + Pi/6.0;
          du = 0.01*Math.sin(a3);
          dv = 0.01*Math.cos(a3);
          u3 = u2 - du;
          v3 = v2 - dv;
          g.drawLine(scalex(u2), scaley(v2),
                     scalex(u3), scaley(v3));
          a4 = a - Pi/6.0;
          du = 0.01*Math.sin(a4);
          dv = 0.01*Math.cos(a4);
          u4 = u2 - du;
          v4 = v2 - dv;
          g.drawLine(scalex(u2), scaley(v2),
                     scalex(u4), scaley(v4));

      } // end j
    } // end i
  } // end paint

  void read_data() throws IOException // big ugly input method
  {
    try
    {
      BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
      String input_line;
      double amount;
      int len;
      int index;
      int last;
   
      System.out.println("read_data running");
      input_line = in.readLine(); // nxx nyy 
      System.out.println("input: "+input_line);
      len = input_line.length();
      index = 0; // nxx
      if(debug) System.out.println("index="+index);
      last = input_line.indexOf(' ',index);
      if(debug) System.out.println("last="+last);
      if(debug) System.out.println(input_line.substring(index,last)+
			  "| len="+(input_line.substring(index,last).length()));
      nxx = Integer.parseInt(input_line.substring(index,last));
      System.out.println("nxx="+nxx);
      index = input_line.indexOf(' ',index); // nyy
      if(debug) System.out.println("index="+index);
      last = input_line.indexOf(' ',index+1);
      if(debug) System.out.println("last="+last);
      if(debug) System.out.println(input_line.substring(index+1,last));
      nyy = Integer.parseInt(input_line.substring(index+1,last));
      System.out.println("nyy="+nyy);
      nxy = nxx*nyy;
      System.out.println("about to allocate "+(5*(nxy+1))+" doubles");
      xx = new double[nxy+1];
      yy = new double[nxy+1];
      zz = new double[nxy+1];
      uu = new double[nxy+1];
      vv = new double[nxy+1];
      n_input = 0;

      // read data points, last index varies by 1
      input_line = in.readLine(); // tested for short in 'while'
      while(input_line.length()>6) // exit on blank or short line
      {
	if(debug && n_input==0) System.out.println("input: "+input_line);
        len = input_line.length();
        index = 0; // first x
        if(debug && n_input==0) System.out.println("index="+index);
        last = input_line.indexOf(' ',index+1);
        if(debug && n_input==0) System.out.println("last="+last);
        amount = Double.parseDouble(input_line.substring(index,last));
        if(debug && n_input==0) System.out.println("amount="+amount);
        xx[n_input] = amount;
        index = last+1; // second y
        if(debug && n_input==0) System.out.println("index="+index);
        last = input_line.indexOf(' ',index);
        if(debug && n_input==0) System.out.println("last="+last);
        amount = Double.parseDouble(input_line.substring(index,last));
        if(debug && n_input==0) System.out.println("amount="+amount);
        yy[n_input] = amount;
        index = last+1; // third z
        if(debug && n_input==0) System.out.println("index="+index);
        last = input_line.indexOf(' ',index);
        if(debug && n_input==0) System.out.println("last="+last);
        amount = Double.parseDouble(input_line.substring(index,last));
        if(debug && n_input==0) System.out.println("amount="+amount);
        zz[n_input] = amount;
        index = last+1; // fourth u
        if(debug && n_input==0) System.out.println("index="+index);
        last = input_line.indexOf(' ',index);
        if(debug && n_input==0) System.out.println("last="+last);
        amount = Double.parseDouble(input_line.substring(index,last));
        if(debug && n_input==0) System.out.println("amount="+amount);
        uu[n_input] = amount;
        index = last+1; // fifth v
        if(debug && n_input==0) System.out.println("index="+index);
        last = input_line.indexOf(' ',index);
        if(last<index) last=len;
        if(debug && n_input==0) System.out.println("last="+last);
        amount = Double.parseDouble(input_line.substring(index,last));
        if(debug && n_input==0) System.out.println("amount="+amount);
        vv[n_input] = amount;

        if(n_input==0)
	{
	  xmin = xx[n_input];
	  xmax = xx[n_input];
	  ymin = yy[n_input];
	  ymax = yy[n_input];
	  zmin = zz[n_input];
	  zmax = zz[n_input];
	  umin = uu[n_input];
	  umax = uu[n_input];
	  vmin = vv[n_input];
	  vmax = vv[n_input];
          System.out.println("first x="+xmin+", y="+ymin+", z="+zmin);
	}
	else
	{
	  xmin = Math.min(xmin,xx[n_input]);
	  xmax = Math.max(xmax,xx[n_input]);
	  ymin = Math.min(ymin,yy[n_input]);
	  ymax = Math.max(ymax,yy[n_input]);
	  zmin = Math.min(zmin,zz[n_input]);
	  zmax = Math.max(zmax,zz[n_input]);
	  umin = Math.min(umin,uu[n_input]);
	  umax = Math.max(umax,uu[n_input]);
	  vmin = Math.min(vmin,vv[n_input]);
	  vmax = Math.max(vmax,vv[n_input]);
	}
        n_input++;
        if(n_input>=nxy) break;
        input_line = in.readLine(); // done with this line, read next
      } // end while
    } // end try
    catch(IOException exception)
    {
      System.out.println(exception);
    }
    System.out.println("read_data finished, n_input="+n_input);
    System.out.println("xmin="+xmin+", xmax="+xmax+", last="+xx[nxy-1]);
    System.out.println("ymin="+ymin+", ymax="+ymax+", last="+yy[nxy-1]);
    System.out.println("zmin="+zmin+", zmax="+zmax+", last="+zz[nxy-1]);
    System.out.println("umin="+umin+", umax="+umax+", last="+uu[nxy-1]);
    System.out.println("vmin="+vmin+", vmax="+vmax+", last="+vv[nxy-1]);
    
    for(int i=0; i<nxy; i++) 
    {
      xx[i] = (xx[i]-xmin)/(xmax-xmin); // normalize all to 0.0 .. 1.0
      yy[i] = (yy[i]-ymin)/(ymax-ymin);
      zz[i] = (zz[i]-zmin)/(zmax-zmin);
      uu[i] = 2.0*(uu[i]-umin)/(umax-umin)-1.0; // -1.0 .. 1.0
      vv[i] = 2.0*(vv[i]-vmin)/(vmax-vmin)-1.0;
    }
  } // end read_data
 
  public static void main(String args[])
  {
    new VelocityPlot1();
  }
}