Bezier曲线和线类：路口和其他基本方法

language: ActionScript3 basic geom classes: Bezier, Line, Intersection. There are two methods, that are used in ActionScript drawing: lineTo() and curveTo() and realize sengment and Bezier second-order curve drawing correspondingly. There are tools in Flash IDE to draw curves with Bezier third-order curves, but during the compilation process they are approximated with second-order curves. As the result, all shapes in compiled SWF-file become segments or Bezier second-order curves. That"s why we encounter a group of tasks, that need mathematical engine to work with segments and Bezier second-order curves.