Flash iOS Apps Cookbook

Using Cache as Bitmap

Rasterization can be expensive and should be minimized. For display objects that only experience translation along the X and Y axes, there is a technique available that removes the need for that object to be re-rasterized. This technique is known as Cache as Bitmap and in most circumstances can accelerate the rendering performance of your application.

Cache as Bitmap takes a display object and generates a bitmap representation of it internally. The cached bitmap is then used for rendering rather than re-rasterizing the original display object. This can result in huge performance gains, particularly when working with complex vector artwork, which can be CPU-intensive to rasterize.

Normally, when a display object changes position, ...