2D图形

package GUI;import java.awt.*;import javax.swing.*;import java.awt.geom.*;             //提供用于在与二维几何形状相关的对象上定义和执行操作的 Java 2D 类。/** * * @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);//给定左上角、宽、高绘制一个矩形        g2.draw(rect);        Ellipse2D ellipse = new Ellipse2D.Double();        ellipse.setFrame(rect);         //将ellipse的框架设定为指定的rect        g2.draw(ellipse);        g2.draw(new Line2D.Double(leftX,topY,leftX+width,topY+height));   //绘制对角线        double centerX = rect.getCenterX();    //得到中心点        double centerY = rect.getCenterY();        double radius = 150;        Ellipse2D circle = new Ellipse2D.Double();        circle.setFrameFromCenter(centerX,centerY,centerX+radius,centerY+radius);//根据中心点坐标设置框架        g2.draw(circle);    }    public Dimension getPreferredSize()    {        return new Dimension(DEFAULT_WIDTH,DEFAULT_HEIGHT);    }}