采用鼠标输入顶点的方法确定待填充多边形；实 现多边形扫描转换算法完成对该多边形的填充， 包括实现边表与活跃边表的构造，填充图案为自定义-The method used to determine mouse input vertex to be filled polygons polygon scan conversion algorithm to complete the polygon fill, including the realization of side tables with