/* Numerical Simuration of Advection Equation */
/* Written by N.Umemura, 2001.8.29 */

import java.applet.*;
import java.awt.*;
import java.lang.Math;
import java.awt.Graphics;
import java.awt.Event;

public class isou2 extends Applet{

		int array=360;
		int arraymax=array+5;

		int theta=0;
		double c=0.1;
		double psi[]=new double[arraymax];
		double psi_exact[]=new double[arraymax];
		double psi_perc[]=new double[arraymax];
		int paint_psi[]=new int[arraymax];
		int paint_theta[]=new int[arraymax];

		int	paint_margin_top=200;
		int	paint_margin_left=50;
		int extend_top=100;
		int extend_left=100;
		int font_margin=5;

		String items[]={"0.1","0.2","0.3","0.4","0.5","0.6","0.7","0.8","0.9","1.0"};
		Choice choice=new Choice();

	public boolean action(Event e,Object o){
		if(e.target instanceof Choice){
			if((String)o =="0.1"){c=0.1;}
			else if((String)o =="0.2"){c=0.2;}
			else if((String)o =="0.3"){c=0.3;}
			else if((String)o =="0.4"){c=0.4;}
			else if((String)o =="0.5"){c=0.5;}
			else if((String)o =="0.6"){c=0.6;}
			else if((String)o =="0.7"){c=0.7;}
			else if((String)o =="0.8"){c=0.8;}
			else if((String)o =="0.9"){c=0.9;}
			else if((String)o =="1.0"){c=1.0;}
			repaint();
			return true;
		}else{
			return false;
		}
	}


	
	public void init(){
		setLayout(new BorderLayout());
		Panel p = new Panel();
		for(int i=0; i<items.length; i++){
			choice.addItem(items[i]);
			p.add(choice);
		}
		p.add(new Label("クーラン数　c ="));
		p.add(choice);
		add(p,"South");
		setBackground(new Color(255,255,255));
	}


	public void paint(Graphics g){
		System.out.println("c=" + c + " start -------------------------------");
		for(theta=1; theta<=180; ++theta){
			double theta_rad=(double)theta/180*Math.PI;		// [degree]から[rad]へ変換
			double tmp=(c*Math.sin(theta_rad))/(1-c*(1-Math.cos(theta_rad)));
			psi[theta]=-Math.atan(tmp)*180/Math.PI;		// atanへ[rad]で読み込ませて[degree]で取り出す
			psi_exact[theta]=(double)(-(int)(c*10)*theta)/10;
			psi_perc[theta]=psi[theta]/psi_exact[theta];
			
			if(c==0.5 || c==1.0){
				psi_perc[theta]=Math.round(psi_perc[theta]+0.0000001);
			}
			
			paint_theta[theta]=(int)(theta_rad*extend_left+paint_margin_left);
			paint_psi[theta]=(paint_margin_top-(int)(psi_perc[theta]*extend_top));
				System.out.println("theta=" + theta_rad + "	psi/psi_exact=" + psi_perc[theta]);	// 数値出力

			if(theta>1){
				int theta_min=theta-1;
				g.drawLine(paint_theta[theta_min],paint_psi[theta_min],paint_theta[theta],paint_psi[theta]);
				g.drawLine(paint_margin_left,50,paint_margin_left,330);		// 縦軸
				g.drawLine(20,paint_margin_top,400,paint_margin_top);			// 横軸
				g.drawLine(paint_margin_left-3,100,paint_margin_left+3,100);
				g.drawString("1.0",paint_margin_left-20,105);
				g.drawString("0",paint_margin_left-20,215);
				g.drawLine(paint_margin_left-3,300,paint_margin_left+3,300);
				g.drawString("-1.0",paint_margin_left-30,305);
				g.drawString("ψ/ψexact",30,40);
				g.drawString("rad",420,205);
			}
			if(theta==180){
				g.drawLine(paint_theta[90],paint_margin_top-3,paint_theta[90],paint_margin_top+3);
				g.drawString("PI/4",paint_theta[90]-10,215);
				g.drawLine(paint_theta[180],paint_margin_top-3,paint_theta[180],paint_margin_top+3);
				g.drawString("PI/2",paint_theta[180]-10,215);
				}
		}

	}


}	// End of class