import java.awt.*;
import java.awt.geom.*;
import javax.swing.*;
public class DrawDemo {
public static void main(String[] args) {
DrawFrame frame = new DrawFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.show();
}
}/**
一个frame中包含一个panel用来画图
*/
class DrawFrame extends JFrame {
public DrawFrame() {
setTitle("DrawDemo");
setSize(DEFAULT_WIDTH, DEFAULT_HEIGHT);
// 将 panel 加到 frame
DrawPanel panel = new DrawPanel();
Container contentPane = getContentPane();
contentPane.add(panel);
}
public static final int DEFAULT_WIDTH = 400;
public static final int DEFAULT_HEIGHT = 400;
}/**
用来显示矩形和椭圆的panel
*/
class DrawPanel extends JPanel {
public void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2 = (Graphics2D) g;
// 画矩形
double leftX = 100;
double topY = 100;
double width = 200;
double height = 150;
Rectangle2D rect = new Rectangle2D.Double(leftX, topY, width, height);
g2.draw(rect);
// 画rect的内切椭圆
Ellipse2D ellipse = new Ellipse2D.Double();
ellipse.setFrame(rect);
g2.draw(ellipse);
// 画一条对角线
g2.draw(new Line2D.Double(leftX, topY, leftX + width, topY + height));
// 画一个同心的圆
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);
}
}以上不知道符合不符合要求。
