用于历史曲线的绘制，可以清晰地显示数据的变化趋势。-for the historical curve, the drawing can be a clear indication of the trend data.

VC++ 编写的实时趋势曲线控件，该控件可以很好的将工业控制过程中的实时参数进行动态显示，界面美观大方，使用方便快捷。-Real-time trend curve control VC++ written, the control can be a very good real-time industrial process control parameters for dynamic display, elegant interface, easy to use and fast.

qt 极坐标趋势窗口控件，使用前要先安装qwt。-qt s plot windows control,install qwt before using