创建画笔工具

package com.mr.draw;

import java.awt.Color;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.event.MouseMotionAdapter;
import java.awt.image.BufferedImage;

import javax.swing.JFrame;

public class DrawPictureFrame extends JFrame {
    BufferedImage image = new BufferedImage(570, 390,
            BufferedImage.TYPE_INT_BGR);
    Graphics gs = image.getGraphics();
    Graphics2D g = (Graphics2D) gs;
    DrawPictureCanvas canvas = new DrawPictureCanvas();
    Color foreColor = Color.BLACK;
    Color backgroungColor = Color.WHITE;
    int x = -1;
    int y = -1;
    boolean rubber = false;

    public DrawPictureFrame() {
        setResizable(false);
        setTitle("画图程序");
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setBounds(500, 100, 574, 460);
        init();
        addListener();
    }

    private void addListener() {
        // TODO Auto-generated method stub
        canvas.addMouseMotionListener(new MouseMotionAdapter() {
        public void mouseDragged(final MouseEvent e) {
            if (x>0&&y>0) {
                if (rubber) {
                    g.setColor(backgroungColor);
                    g.fillRect(x,y,10,10);
                }else{
                    g.drawLine(x,y,e.getX(),e.getY());
                }
            }
            x=e.getX();
            y=e.getY();
            canvas.repaint();
        }     
        });
        canvas.addMouseListener(new MouseAdapter() {
            public void mouseReleased(final MouseEvent arg0){
       x=-1;
       y=-1;
            }
        });
    }

    private void init() {
        // TODO Auto-generated method stub
        g.setColor(backgroungColor);
        g.fillRect(0, 0, 570, 390);
        g.setColor(foreColor);
        canvas.setImage(image);
        getContentPane().add(canvas);
    }

    public static void main(String[] args) {
        DrawPictureFrame frame = new DrawPictureFrame();
        frame.setVisible(true);
    }
}