最近在研究GIS，在地图上绘制东西，flex 绘制出来的直线，定点，自己改造为动态获取起始点。-Recent research in GIS, on the map rendering things, flex draw out straight line, fixed point, oneself transform for dynamic acquisition starting point.

一个定点，做另一个点与这个点的直线和平行线-A fixed point, another point to make this point in a straight line and parallel lines