import java.awt.*;

import java.awt.geom.*;

import javax.swing.*;

/*

* 窗口中绘图(长方形，椭圆，对角线，圆)

* class structure

* Point2D-Point

* -Ellipse2D

* Shape-Rectangular Shape |

* |-Rectangel2D-Rectangle

* ---Line2D

*

* -Rectangle2D.Float

* Rectangele2D-|

* -Rectangle2d.Double

*/

public class DrawTest {

public static void main(String[] args){

EventQueue.invokeLater(new Runnable()

{

public void run()

{

DrawFrame frame = new DrawFrame();

frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

frame.setVisible(true);

}

});

}

}

/**

* A frame that contains apanel with drawings

*/

class DrawFrame extends JFrame

{

public DrawFrame()

{

setTitle("DrawFrame");

setSize(DEFAULT_WIDTH,DEFAULT_HEIGHT);

//add a panel to frame

DrawComponent component = new DrawComponent();

add(component);

}

public static final int DEFAULT_WIDTH = 400;

public static final int DEFAULT_HEIGHT = 400;

}

/**

* A component that displays rectangles and ellipses

*/

class DrawComponent extends JComponent

{

public void paintComponent(Graphics g)

{

Graphics2D g2 = (Graphics2D)g;

//draw a rectangle

double leftX = 100;

double topY = 100;

double width = 200;

double height = 150;

Rectangle2D rect = new Rectangle2D.Double(leftX,topY,width,height);

g2.draw(rect);

//draw a ellipse

//*Ellipse2D ellipse = new Ellipse2D.Double(leftX,topY,width,height);

Ellipse2D ellipse = new Ellipse2D.Double();

ellipse.setFrame(rect);

g2.draw(ellipse);

//draw a diagonal line

g2.draw(new Line2D.Double(leftX,topY,leftX+width,topY+height));

//draw a circle with the same center

double centerX = leftX + width/2;

double centerY = topY + height/2;

double radius = 150;

Ellipse2D circle = new Ellipse2D.Double();

circle.setFrameFromCenter(centerX, centerY,centerX+radius,centerY+radius);

//*Ellipse2D circle = new Ellipse2D.Double(leftX,topY,radius*2,radius*2);

g2.draw(circle);

}

}