实现了任意2D图形的扫描填充，任意的图多边形、凹多边形都可以使用该算法。-Achieve a scanning 2D graphics fill any arbitrary FIG polygon concave polygon can use this algorithm.

读取DXF文件和保存DXF文件,处理通用实体，并且加入了Polygon和Polyface的接口-his is not a complete DXF reader package, but it handles most entities that are commonly found. With this release I ve added the Polygon mesh and Polyface mesh varieties of POLYLINE, so a great