drawfunction_for_ppcandpc

代码说明：

  可用于pocket pc 和 pc上的轨迹描绘程序，通过给出坐标描绘出轨迹。并可以进行移动缩放，以及坐标显示等功能。(Can be used for pocket pc and pc on the track of the procedures described by the coordinates given depict the trajectory. And can move the zoom, as well as the coordinates display functions.)