//
//  Exp.java
// Newton's Cooling Function
//
//  Created by Chris Thiel on Mon Nov 18 2003.
//  Copyright (c) 2003 Chris Thiel. All rights reserved.
//  A simple Java applet for students to interact with
//  
//

import java.awt.*;
import java.applet.*;
import java.lang.*;
import java.io.*;
import java.awt.event.*;
import java.awt.Graphics;
public class Exp extends Applet implements AdjustmentListener {

   	int rx = 50;  //red dot in screen coords
        int ry = 300; //75 degrees in screen cords
        int bx = 120; // blue dot
        int by = 132; // heated to 180 in screen coords
        int gx = 0;   //green dot
        int gy = 420;
	 Scrollbar horiz=new Scrollbar(Scrollbar.HORIZONTAL,1,20,0,60);

	public void init() {
		this.setBackground(Color.cyan);
               
                //the next line adds an adjusment listener to horiz so it can
                //have events processed when the scroller is moved
                 setLayout(new BorderLayout());

                add("South", horiz);
            horiz.addAdjustmentListener(this);
	}
//adjustmentValueChanged() is the method that handles AdjustmentEvents
    //which is when the value of a Scrollbar is changed
    public void adjustmentValueChanged(AdjustmentEvent e){
        //the next if statement checks to see if the AdjustmentEvent
        //came from horiz
        if(e.getAdjustable()==horiz){
            //sets the text in num to the value of horiz
            gx = horiz.getValue();
            repaint();
        }
           }	
	public void paint(Graphics g) {
		double x, y, delta, m, y1, y2;
                double r,h,k,uy; 
		int x_int, x_int_old, y_int, y_int_old, y1_int, y2_int;
		float mf;
		g.setColor(Color.black);
		g.drawLine(120,0,120,440);
		g.drawLine(0,420,440,420);
                g.drawString("250",90,25);
		g.drawString("200",90,25+80);
		g.drawString("150",90,25+160);
		g.drawString("100",90,25+240);
		g.drawString("50",100,25+320);
		g.drawString("time",10,435);
		g.drawString("0.0",100,435);
		g.drawString("10",190,435);
		g.drawString("20",270,435);
		g.drawString("30",350,435);
                g.drawString("40",430,435);
		g.setColor(Color.blue);
                // Cooling Formula y= r + (h-r)e^(kx)
                r = (250.0/400.0)*(420 - (double)(ry));  //red y goes from 20 to 420, so convert to 250 to 0
                k = (-2.0/400.0)*((double)(rx)-20); // red x goes from 20 to 420 so convert to 0 to -2.0
                h = (250.0/400.0)*(420 - (double)(by));  //red y goes from 20 to 420, so convert to 250 to 0
                //gx = (40.0/400.0)*((double)(gx)-20
		//k = -.1627;
                x = -0.5;
		delta = .5;
		x_int_old = 120;
		y_int_old = 320;
		for(int i=1;i<=270;i++) {
			x = x + delta;
			y = r + (h-r)* Math.pow(Math.E,k*x);
                        
			x_int = Math.round(Math.round(120+8*x));
			y_int = Math.round(Math.round(420-(400.0/250.0)*y));
			g.drawLine(x_int_old,y_int_old,x_int,y_int);
			x_int_old = x_int;
			y_int_old = y_int;
		}
               
                
                g.setColor(Color.blue);
		//g.fillOval(bx-5,by-5,10,10);
		g.fillOval(120-5,by-5,10,10);
		g.setColor(Color.red);
		g.fillOval(rx-5,ry-5,10,10);

		g.drawString("Room Temp r="+Double.toString(r),330,40);
                g.drawString("k = "+Double.toString(k),330,60);
                g.drawLine(0, ry, 500, ry);
                g.setColor(Color.blue);
                g.drawString(" Heated to h="+Double.toString(h),130,40);
                g.setColor(Color.magenta);
               
                uy = r + (h-r)* Math.pow(Math.E,k*gx);
                gy = Math.round(Math.round(420-(400.0/250.0)*uy));
                g.drawString(" ("+Integer.toString(gx)+","+Double.toString(uy)+")", 120+8*gx, gy);
       		g.drawString("u(t) = r + (h-r)e",130,60);
                g.drawString("kt",230,55);

                g.drawLine(120, gy, 120+8*gx,gy);
                g.drawLine(120+8*gx,420,120+8*gx,gy);		
	}
	
	public boolean mouseDrag(Event e, int mx, int my) {
        // check if inside red or blue dot
        // put in approporiate 
        
		// to ignore y if ((my < 410) || (my > 430)) return true;
                //check for extremes
                if (my < 20) my = 20;
		if (my > 420) my =420;
		if (mx < 20) mx = 20;
		if (mx > 420) mx =420;
        if (Math.abs(my-ry)<17 && Math.abs(mx-rx)<17){        
		rx = mx;
                ry = my;
                repaint();
		return true;
            }
        if (Math.abs(my-by)<17 && Math.abs(mx-bx)<17){        
		bx = mx;
                by = my;
                repaint();
		return true;
            }
        return true;
	}
}