flex系列疑问

1，BitMap和BitMapData有啥关系
A BitmapData object can be drawn to the screen by a Bitmap object in one of two ways: by using the vector renderer as a fill-bitmap shape, or by using a faster pixel-copying routine. The pixel-copying routine is substantially faster than the vector renderer
2,Bitmap最大限制
In AIR 1.5 and Flash Player 10, the maximum size for a BitmapData object is 8,192 pixels in width or height, and the total number of pixels cannot exceed 16,777,216 pixels.

3 include关键字是什么意思

4,[Event(name="scroll", type="mx.events.ScrollEvent")] 这是什么语法