说明：  用普通方法显示BMP位图，占内存大，速度慢，在图形缩小时，失真严重,在低颜色位数的设备上显示高颜色位数的图形图形时失真大。本文采用视频函数显示BMP位图，可以消除以上的缺点。
(Ordinary methods of display BMP bitmap, or memory, and slow to narrow in the graphics when a serious distortion in the low-color display device median median high-color graphics graphics distortion when large. In this paper, the video function display BMP bitmap, you can eliminate the above shortcomings.)