2D 그래픽

package GUI;
import java.awt.*;
import javax.swing.*;
import java.awt.geom.*;             //  Java 2D  。
/**
 *
 * @author Zhu Zhengyan
 */
public class DrawTest {
    public static void main(String[] args)
    {
        EventQueue.invokeLater(()->
        {
            JFrame frame = new DrawFrame();
            frame.setTitle("DrawTest");
            frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
            frame.setVisible(true);
        });
    }
}
class DrawFrame extends JFrame
{
    public DrawFrame()
    {
        add(new DrawComponent());
        pack();
    }
}
class DrawComponent extends JComponent
{
    private static final int DEFAULT_WIDTH = 400;
    private static final int DEFAULT_HEIGHT = 400;
    public void paintComponent(Graphics g)
    {
        Graphics2D g2 = (Graphics2D) g;
        double leftX = 100;
        double topY = 100;
        double width = 200;
        double height = 150;
        Rectangle2D rect = new Rectangle2D.Double(leftX,topY,width,height);// 、 、 
        g2.draw(rect);
        Ellipse2D ellipse = new Ellipse2D.Double();
        ellipse.setFrame(rect);         // ellipse rect
        g2.draw(ellipse);
        g2.draw(new Line2D.Double(leftX,topY,leftX+width,topY+height));   // 
        double centerX = rect.getCenterX();    // 
        double centerY = rect.getCenterY();
        double radius = 150;
        Ellipse2D circle = new Ellipse2D.Double();
        circle.setFrameFromCenter(centerX,centerY,centerX+radius,centerY+radius);// 
        g2.draw(circle);
    }
    public Dimension getPreferredSize()
    {
        return new Dimension(DEFAULT_WIDTH,DEFAULT_HEIGHT);
    }
}