// wire.java　電線アプレット
// Dr.DOTIMPACT 2000/8/19

import java.applet.Applet;
import java.awt.*;

public class wire extends Applet implements Runnable {
    // スレッド
    Thread th;

    // ダブルバッファ
    Image buf;
    Graphics bufg;

    // 画面には同時に２車両しか見えないと仮定
    int tx1;
    boolean go;
    
public void init() {
  th = null;

  // ダブルバッファ準備
  buf = createImage(size().width, size().height);
  bufg = buf.getGraphics();
  whiteout();

  go = false;
  tx1 = Integer.MAX_VALUE;
}
public void start() {
    if(th == null) {
	th = new Thread(this);
	th.start();
    }
}
public void stop() {
    if(th != null) {
	th.stop();
	th = null;
    }
}
public void update(Graphics g) {
    paint(g);
}
public void paint(Graphics g) {
    g.drawImage(buf, 0, 0, this);
}
public boolean mouseEnter(Event ev, int x, int y) {
    go = true;
  tx1 = 4000;
    return true;
}
public boolean mouseExit(Event ev, int x, int y) {
    go = false;
    return true;
}

public void run()
{
  for(;;) {
    try {
      Thread.sleep(100);
    } catch(Exception e) {}
    
    if(go || tx1 != Integer.MAX_VALUE) {
      tx1 = tx1 - 200;
      draw();
      repaint();
    }
    if(tx1 < -4000-size().width) {
      if(go) {
        tx1 = 4000;
      } else {
        tx1 = Integer.MAX_VALUE;
      }
    }
  }
}

public void draw()
{
  whiteout();

  drawWire(tx1, size().height/2, 0.0001);
  drawWire(tx1+100, size().height/2, 0.0001);
  drawWire(tx1+500, size().height/4, 0.0004);
}

public void drawWire(int _x0, int _y0, double _ratio) {
  int step = 20;
  int x1;
  double y, y1;

  x1 = -1 * step;
  y1 = _y0 - _ratio * (x1 - _x0) * (x1 - _x0);
  for(int x=0 ; x <= size().width ; x += step) {
    y = _y0 - 0.00001 * (x - _x0) * (x - _x0);
    bufg.drawLine(x1, (int)y1, x, (int)y);
    x1 = x;
    y1 = y;
  }
}

public void whiteout()
{
  bufg.setColor(Color.white);
	bufg.fillRect(0,0, size().width, size().height);
  bufg.setColor(Color.black);
  bufg.drawRect(0,0, size().width-1, size().height-1);
}


}