/*********************************/
/*			   	 */
/*    　  翼のカオスを描く	 */
/*			    	 */
/*    1997/ 5/20  宍戸　輝光	 */
/*			   	 */
/*********************************/

import java.awt.*;

public class tubasa extends java.applet.Applet implements Runnable {

	Image screen;
	Graphics g_screen;

	Panel ap,bp,btp;
	Button ctrb;
	TextField at,bt;
	Label rangel,al,bl;
	
	Thread runner=null;

	int i,j;
	double a,b,x,y,xn,yn;

	boolean doing;

	public void start(){

		resize(460,360);

		setBackground(Color.lightGray);
		setFont(new Font("TimesRoman",Font.PLAIN,12));

		screen=createImage(302,302); /* 表示用イメージ */
		g_screen=screen.getGraphics();

		g_screen.setColor(Color.black);
		g_screen.fillRect(1,1,300,300);
		g_screen.setColor(Color.white);
		g_screen.drawRect(0,0,301,301);

		ctrb=new Button("G o");

		rangel=new Label("Range");
		al=new Label("a=");
		bl=new Label("b=");

		at=new TextField(8);
		at.setBackground(Color.white);
		bt=new TextField(8);
		bt.setBackground(Color.white);

		this.setLayout((LayoutManager)null);

		ap=new Panel();
		add(ap);
		ap.reshape(316,32,120,32);
		ap.setLayout(new FlowLayout(FlowLayout.LEFT,4,4));

		bp=new Panel();
		add(bp);
		bp.reshape(316,80,120,32);
		bp.setLayout(new FlowLayout(FlowLayout.LEFT,4,4));

		btp=new Panel();
		add(btp);
		btp.reshape(64,316,240,32);

		ap.add(al);
		ap.add(at);

		bp.add(bl);
		bp.add(bt);

		btp.add(ctrb);

		doing=false;
		a=-0.8;
		b=0.008;

		at.setText(String.valueOf(a));
		bt.setText(String.valueOf(b));

		if (runner==null) {

			runner=new Thread(this); /*スレッド生成*/
			runner.start();

		}

	}

	public void stop() { /*終了時にスレッド破棄*/

		if (runner!=null) {

			runner.stop();
			runner=null;

		}

	}

	public void run() {

		while (true) {

			if (doing) /* 描画中 */
				draw_screen();


		};

	}

	public void draw_screen() { /* グラフ描画 */

		Color co;

		g_screen.setColor(Color.black);
		g_screen.fillRect(0,0,300,300);
		repaint();

		x=0.1;
		y=0;

		for (i=0;i<1024;i++) {

			for (j=0;j<256;j++) {

				xn=y+b*(1.0-0.05*y*y)*y+a*x+(2.0*(1.0-a)*x*x)/(1.0+x*x);
				yn=-x+a*xn+(2.0*(1.0-a)*xn*xn)/(1.0+xn*xn);

				x=xn;
				y=yn;

				co=new Color(255,(i % 256),j);

				g_screen.setColor(co);

				g_screen.fillRect((int)(xn*7+150),300-(int)(yn*7+150),1,1);

			}

			repaint();

			if (!doing) {

				ctrb.setLabel("G o");
				return;

			}

		}

		ctrb.setLabel("G o");

		doing=false;

	}

	public boolean action(Event evt,Object what) {

		if (evt.target==ctrb) { /* 開始・中断 */

			if (doing) { /* 中断 */

				ctrb.setLabel("G o");
				doing=false;
				return true;

			}

			try { /* aの設定 */
				a=Double.valueOf(at.getText()).doubleValue();
			} catch (Exception e) {
				a=-1.0;
				at.setText(String.valueOf(a));
			}

			try { /* bの設定 */
				b=Double.valueOf(bt.getText()).doubleValue();
			} catch (Exception e) {
				b=0.1;
				bt.setText(String.valueOf(b));
			}

			ctrb.setLabel("Stop");
			doing=true;

			return true;

		}

		return false;

	}

	public void paint(Graphics g){

		g.drawImage(screen,7,7,this);

	}

	public void update(Graphics g){

		paint(g);

	}

}