Flash's drawing tools and rendering engine makes it convenient to create a deeply nested display list. When examining artwork created in Flash, it is fairly common to have to drill down into the top-level clip for several levels and navigate through a complex hierarchical structure until you find your target display object.
Unfortunately, while a desktop computer will be able to easily render complex scenes, the same content running on an iOS device may degrade performance. Deeply nested display lists also cause long event chains that can further hurt the performance. A touch event, for example, must traverse the display list in order to determine the display objects that are to receive the event.
When porting to iOS, rendering is often the biggest performance bottleneck. Consider flattening your display list in order to keep your application's frame rate as high as possible.
We will see how this is done by completely flattening an example nested display list.