When using the flash drawing api to create drawings on the stage, after many lines/shapes you will experience a significant slowing of the system. This is because flash has to draw each line every frame. Flash 8, provided a solution to this problem. You can now render your vector drawing to a bitmap.
Many of the examples of how to do this a quiet complex because they have a lot of pretty drawing code in them. The system is pretty easy once you understand it, so I’ve put together a really simple Actionscript 3 example. (note that AS2 is a bit different but the theory is the same)
Code comments provide explanation in the the source code.
Source: bitmapexample.as
Example: Bitmap_Example.swf
