实时曲线类的改进增加功能: 1)采样数据存盘和加载 2)演示程序中可以实现图形的打印预览和打印功能,曲线从原点开始-Improvement of real-time curve of increasing the number of functional categories: 1) sampling data to disk and load 2) presentation graphics program can print and print preview function, curve