本程序采用内存作图的方式，高效的完成曲线绘制。实际应用中可以在此基础上进行扩展，现有功能光标跟随、曲线移动、按上下键缩放等。-This procedure used the way of memory mapping, and efficient completion of curve drawing. Practical applications can be conducted on the basis expansion of the existing features to follow