JAVA 鼠标画直线举行椭圆

package GUIMouse;

//MouseDraw 
import java.awt.*;
import java.awt.event.*;
import java.util.*;
import javax.swing.*;

public class GUIMouse {
	private static JMenuBar jMenuBar1;

	public static void main(String[] args) {
		MouseFrame frame = new MouseFrame();
		frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		{
			jMenuBar1 = new JMenuBar();
			setJMenuBar(jMenuBar1);
		}
		frame.show();
		pack();
	}

	private static void pack() {
		// TODO Auto-generated method stub

	}

	private static void setJMenuBar(JMenuBar menuBar1) {
		// TODO Auto-generated method stub

	}
}

class MouseFrame extends JFrame {
	private Button bt;
	private Button bt1;
	private Button bt2;
	private Button bt3;

	public MouseFrame() {
		setTitle("利用鼠标画图");
		setSize(WIDTH, HEIGHT);
		// 将panel加入到frame
		BorderLayout bl = new BorderLayout();
		setLayout(bl);
		bt = new Button("Auto");
		bt1 = new Button("Line");
		bt2 = new Button("Qval");
		bt3 = new Button("Rect");
		MousePanel panel = new MousePanel();
		Container contentPane = getContentPane();
		contentPane.add(bt, BorderLayout.NORTH);
		contentPane.add(bt1, BorderLayout.EAST);
		contentPane.add(bt2, BorderLayout.SOUTH);
		contentPane.add(bt3, BorderLayout.WEST);
		contentPane.add(panel, BorderLayout.CENTER);
		bt.addActionListener(new SB());
		bt1.addActionListener(new SB());
		bt2.addActionListener(new SB());
		bt3.addActionListener(new SB());
	}

	private class SB implements ActionListener {

		public void actionPerformed(ActionEvent arg0) {
			// TODO Auto-generated method stub
			if (arg0.getSource() == bt) {
				MousePanel.setControl(1);
			}
			if (arg0.getSource() == bt1) {
				MousePanel.setControl(2);
			}
			if (arg0.getSource() == bt2) {
				MousePanel.setControl(4);
			}
			if (arg0.getSource() == bt3) {
				MousePanel.setControl(3);
			}
		}

	}

	public static final int WIDTH = 300;

	public static final int HEIGHT = 200;
}

class MousePanel extends JPanel {
	private Point pt;

	private Point old_Pt;

	private static int Control = 4;

	public MousePanel() {

		// 注册监听器
		addMouseListener(new MouseHandler());
		addMouseMotionListener(new MouseMotionHandler());
	}
	
	public static void setControl(int para){
		Control = para;
	}

	public void paintComponent(Graphics g) {
		if (Control == 1 || Control == 2)
			g.drawLine(pt.x, pt.y, old_Pt.x, old_Pt.y);
		if (Control == 3)
			g.drawRect(pt.x, pt.y, old_Pt.x - pt.x, old_Pt.y - pt.y);
		if (Control == 4)
			g.drawOval(pt.x, pt.y, old_Pt.x - pt.x, old_Pt.y - pt.y);
	}

	private class MouseHandler extends MouseAdapter {
		public void mousePressed(MouseEvent event) {
			if (Control > 1) {
				pt = event.getPoint();
			}
			if (Control == 1) {
				pt = event.getPoint();
				old_Pt = pt;
			}
		}

		public void mouseReleased(MouseEvent event) {
			// 得到鼠标光标的当前位置
			if (Control > 1) {
				old_Pt = event.getPoint();
				repaint();
			}
		}
	}

	private class MouseMotionHandler implements MouseMotionListener {
		public void mouseMoved(MouseEvent event) {
			// 得到鼠标光标的当前位置
		}

		public void mouseDragged(MouseEvent event) {
			// 得到鼠标光标的当前位置
			if (Control == 1) {
				old_Pt = pt;
				pt = event.getPoint();
				repaint();
			}
		}
	}
}