位图示例，在窗口中间放入一幅图片，并且可以用鼠标及键盘对它进行操作-Bitmap example, put a picture in the middle of the window, and it can be used to operate the mouse and keyboard

位图示例，一张图片居中，并且能够用鼠标对它进行操作，键盘也能进行操作，上移下移-Bitmap example, a picture center, and can operate it with the mouse, keyboard, can operate, move down