/**	CosineWaveGrapher.java
*	@author Charles Bell
*	@version Oct 26, 2002
*/

import java.awt.*;
import javax.swing.*;

public class CosineWaveGrapher extends JFrame{
	
	public CosineWaveGrapher(){
		super("CosineWaveGrapher");
		init();
	}
	
	public static void main(String[] args){
		CosineWaveGrapher grapher = new CosineWaveGrapher();
	}
	
	
	public void init(){
		setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		getContentPane().add(new GrapherPanel(), BorderLayout.CENTER);
		pack();
		setLocationRelativeTo(null);
		show();
	}
	
	
	class GrapherPanel extends JPanel{
		
		public GrapherPanel(){
			super();
			setPreferredSize(new Dimension(620,420));
		}
		
		public void paint(Graphics g){
			super.paintComponent(g);
			g.setColor(Color.black);
			g.translate(310, 210);
			g.drawLine(-300, 200, 300, 200); 	//across top
			g.drawLine(-300, 0, 300, 0); 		//across middle
			g.drawLine(-300,-200, 300, -200); //across bottom
			g.drawLine(-300, -200, -300, 200); //down left side
			g.drawLine(-150, -200, -150, 200); //down left side
			g.drawLine(0, -200, 0, 200);		//down middle
			g.drawLine(150, -200, 150, 200);	//down right side
			g.drawLine(300, -200, 300, 200);	//down right side
			char piChar = '\u03c0';
			g.drawString("-2" + piChar, -290, -10);	
			g.drawString("-" + piChar , -140, -10);	
			g.drawString("0" , 10, -10);	
			g.drawString("+" +piChar, 160, -10);	
			g.drawString("+2" +piChar, 270, -10);	
			g.drawString("+1" , 10, -185);	
			g.drawString("-1" , 10, 195);	
			int x0 = -300;
			int y0 = 0;
			int x1 = -300;
			int y1 = 0;
			double pi = Math.PI;
			for (double theta = -2 * pi; theta <= 2 * pi; theta=theta + pi/500){
				x1 = (int) ((theta*300)/(2 * pi));
				y1 = -(int)(200 * Math.cos(theta));
				g.drawLine(x0,y0,x1,y1);
				//System.out.println("x1: " + x1 + " y1: " + y1);
				x0 = x1;
				y0 = y1;				
			}
		}
	}
}