import javax.swing.*;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.RenderingHints;
import java.awt.geom.*;

public class QuadCurve2DTest2 extends JPanel{

  public static void main(String[] args){
    JFrame frame = new JFrame();

    QuadCurve2DTest2 app = new QuadCurve2DTest2();
    frame.getContentPane().add(app);

    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.setBounds(10, 10, 300, 200);
    frame.setTitle("ƒ^ƒCƒgƒ‹");
    frame.setVisible(true);
  }

  public void paintComponent(Graphics g){
    Graphics2D g2 = (Graphics2D)g;

    g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, 
                        RenderingHints.VALUE_ANTIALIAS_ON);

    QuadCurve2D.Double curve = new QuadCurve2D.Double();
    curve.setCurve(60.0d, 40.0d, 220.0d, 30.0d, 120.0d, 140.0d);

    g2.draw(curve);

    double x1 = curve.getX1();
    double y1 = curve.getY1();
    double x2 = curve.getX2();
    double y2 = curve.getY2();
    double ctrlx = curve.getCtrlX();
    double ctrly = curve.getCtrlY();

    g2.draw(new Ellipse2D.Double(x1 - 5.0d, y1 - 5.d, 10.d, 10.0d));
    g2.draw(new Ellipse2D.Double(x2 - 5.0d, y2 - 5.d, 10.d, 10.0d));
    g2.draw(new Ellipse2D.Double(ctrlx - 5.0d, ctrly - 5.d, 10.d, 10.0d));
  }
}