添加鼠标画笔功能

	//鼠标绘制点横纵坐标
	int x = -1;
	int y = -1;
	boolean rubber = false;//橡皮
	
	/*
	 * 构造方法
	 */
	public  DrawPictureFRame() {
		setResizable(false);
		setBounds( 500, 100, 574, 460);
		setDefaultCloseOperation(EXIT_ON_CLOSE);
		setTitle("画图程序");
		init();
		addListener();
	}
	
	private  void addListener() {
		//画板添加鼠标移动事件监听
		canvas.addMouseMotionListener(new MouseMotionAdapter(){
			public void mouseDragged(final MouseEvent e){//拖拽鼠标
				if(x > 0 && y > 0){
					if(rubber){
						g.setColor(backgroundColor);
						g.fillRect(x, y, 10, 10);
					}else{//鼠标划过的位置画直线
						g.drawLine(x, y, e.getX(), e.getY());
					}
				}
				x = e.getX();
				y = e.getY();
				canvas.repaint();//更新画布
			}
		
			
		});
	
	
	canvas.addMouseListener(new MouseAdapter(){
		public void mouseReleased(final MouseEvent arg0){
			 x = -1;
			 y = -1;
		}
	});
	}