import java.util.Date;
import java.applet.*;
import java.awt.Graphics;
import java.awt.event.*;
import java.awt.*;
import Rectangle;
import Line;


public class vecadd extends Applet 
{
    double x1 = 50.0;
    double y1 = 250.;
     int dx;
      int dy;
     int cx = 200;
      int cy = 250;
     int bx = cx;
     int by= cy-100;
    int go = 1;
    int lastx;

double arrowlength=25.;
double angle = 25.;
    double radangle = angle*(Math.PI/180);
    double sinangle = Math.sin(radangle);
    double cosangle = Math.cos(radangle);
     double dx1;
      double dy1;
    double dx2;
     double dy2;
      double squarefunc;
      double dompx;
      double dompy;
    double tim = 0;
    double dtim=0.01;

    static double qvalue = 10;
    static double betavalue = 200;

    double recentx[];
    long recentt[];
    double I_loop=0.;

    int max = 4;
    int j;
    int xcoord, ycoord;
    long lastt;

    int maxtim =1;
    int brectcx;
    int brectcy;

    double dist1;
    double dist2;
    double compx, compx1, compx2;
    double compy, compy1, compy2;
    double dummy = 0.;
    double rada = 100.;
    double ang=Math.PI/6.;

    int x2 = 325;
    int y2 = 240;

    int numline = 2;

    Rectangle rect;
    Line line;

/*
public void Reset()
    {
	x1 = 50.0;
	y1 = 250.;
	go = 1;
	tim = 0;
	repaint();
    }

public void Settvalue(String m)
    {
  	maxtim = new Integer(m).intValue();
    }

public void Setqvalue(String m)
    {
	qvalue = new Double(m).doubleValue();
    }

public void Setbvalue(String m)
    {
	betavalue = new Double(m).doubleValue();
    }

public void SetGo()
    {
	go = 1;
	repaint();
    }
*/
 
public void init()
    {
	setBackground(java.awt.Color.white);
	rect = new Rectangle(0,10,15,(int)x1,(int)y1);
	
 	recentx = new double[max+1];
	recentt = new long[max+1];
	line=new Line(0.0,0.0,0.0,0.0);

    }

public void paint(Graphics g)
    {
	//if(tim==0 && go==1)
//	if(go==1)
//	    {
		//while(tim<maxtim)
		  {    
		   	line.ang = ang;  //the angle of field line measured from horizontal
    			line.emag = 1;

			rect.cx = (int)x1;
			rect.cy = (int)y1;

			g.setColor(java.awt.Color.blue);
                                             dx=rect.cx;
                                             dy=rect.cy;
    			g.drawLine(dx,dy,cx,cy);
                               dompx = dx-cx;
                               dompy=dy-cy;
                               squarefunc = Math.sqrt(Math.pow(dompx,2) + Math.pow(dompy,2));
		dy1 = 1*(arrowlength*((sinangle*dompx-cosangle*dompy)/squarefunc));
		dx1 = -1*(arrowlength*((cosangle*dompx+sinangle*dompy)/squarefunc));
		dy2 = 1*(arrowlength*((-sinangle*dompx-cosangle*dompy)/squarefunc));
		dx2 = -1*(arrowlength*((cosangle*dompx-sinangle*dompy)/squarefunc));
		g.drawLine(dx,dy, dx+(int)dx1,dy+(int)dy1);
		g.drawLine(dx, dy,dx+(int)dx2,dy+(int)dy2);

			g.setColor(java.awt.Color.red);

                                             dx=bx;
                                             dy=by;
    			g.drawLine(dx,dy,cx,cy);
                               dompx = dx-cx;
                               dompy=dy-cy;
                               squarefunc = Math.sqrt(Math.pow(dompx,2) + Math.pow(dompy,2));
		dy1 = 1*(arrowlength*((sinangle*dompx-cosangle*dompy)/squarefunc));
		dx1 = -1*(arrowlength*((cosangle*dompx+sinangle*dompy)/squarefunc));
		dy2 = 1*(arrowlength*((-sinangle*dompx-cosangle*dompy)/squarefunc));
		dx2 = -1*(arrowlength*((cosangle*dompx-sinangle*dompy)/squarefunc));
		g.drawLine(dx,dy, dx+(int)dx1,dy+(int)dy1);
		g.drawLine(dx, dy,dx+(int)dx2,dy+(int)dy2);

			g.setColor(java.awt.Color.black);
                                             dx= bx+rect.cx-cx;
                                             dy= by+rect.cy-cy;
    			g.drawLine(dx,dy,cx,cy);
                               dompx = dx-cx;
                               dompy=dy-cy;
                               squarefunc = Math.sqrt(Math.pow(dompx,2) + Math.pow(dompy,2));
		dy1 = 1*(arrowlength*((sinangle*dompx-cosangle*dompy)/squarefunc));
		dx1 = -1*(arrowlength*((cosangle*dompx+sinangle*dompy)/squarefunc));
		dy2 = 1*(arrowlength*((-sinangle*dompx-cosangle*dompy)/squarefunc));
		dx2 = -1*(arrowlength*((cosangle*dompx-sinangle*dompy)/squarefunc));
		g.drawLine(dx,dy, dx+(int)dx1,dy+(int)dy1);
		g.drawLine(dx, dy,dx+(int)dx2,dy+(int)dy2);



	    brectcx = rect.cx;
	    brectcy = rect.cy;

	    tim+=dtim;
//	    System.out.println("tim=" +tim);

	    //g.setColor(java.awt.Color.white);
	    //g.fillRect(0,0,450,500);
	    g.setColor(java.awt.Color.black);
//	    g.drawOval(225,150,20,(2*(int)rada));
    	 	    }  	   
 //   	    }
}

/*
public boolean mouseMove(Event e, int x, int y)
    {
 
    xcoord = x;
    ycoord = y;
    return true;
    }
*/
 
public boolean mouseDown(Event e, int x, int y)
    {
    xcoord = x;
    ycoord = y;

    if(xcoord < (int)x1 + rect.rw && xcoord > (int)x1-rect.rw && ycoord < (int)y1+rect.rh && ycoord > (int)y1-rect.rh)
   	{
	rect.hit = 1;
	}
	return true;
    }  
 
public boolean mouseUp(Event e, int x, int y)
    {
    rect.hit = 0;
    return true;
    }
 
public boolean mouseDrag(Event e, int x, int y)
    {
    xcoord = x;
    ycoord = y;
    if (rect.hit == 1)
        {
        lastx = rect.cx;
        lastt = new Date().getTime();
 
        if(j <= max)
            {
            recentx[j] = lastx;
            recentt[j] = lastt;
            rect.cx = x;
	    x1 = rect.cx;
            }
        else if(j > max)
            {
            j = 0;
            while(j < max)
                {
                recentx[j] = recentx[(j+1)];
                recentt[j] = recentt[(j+1)];
                j++;
                }
                recentx[j] = lastx;
                recentt[j] = lastt;
                rect.cx = x;
                rect.cy = y;
		x1 = rect.cx;
                             y1 = rect.cy;
            }
        j++;
//        System.out.println("Recentx[0] = " + recentx[0] + " Recentx[1] = " + recentx[1] + " Recentx[2] = " + recentx[2]);
//        System.out.println("Recentt[0] = " + recentt[0] + " Recentt[1] = " + recentt[1] + " Recentt[2] = " + recentt[2]);
//	System.out.println("x=" + x + " y = " + y+ "I_loop  " + I_loop);
         I_loop=recentx[max]-recentx[max-1];
         
        repaint();
        }
    return true;
    }  
}