bitmapData's dimensions (width and height)

programming flash
1

Hi,

I’m new to flex and I have a question concerning bitmapData and its width and height.

Normally you set up bitmapData like this in AS3:


var bd:BitmapData = new BitmapData(100, 100, true, 0x00000000);
var bm:Bitmap = new Bitmap(bd);

But in Flex embedding an an image works like this:


[Embed(source="../../../../../assets/sprites/asteroids/asteroid_32_full.gif")]
public static const Asteroid1:Class;
var imageBM:Bitmap = new Library.Asteroid1();

When using the bitmapData (e.g. imageBM.bitmapData) I don’t have to set up width and height any more. Does the Flash player know the width and height of a bitmapData automatically even when NOT setting up the bitmapData’s width and height? I’m totally unaware about this topic because I don’t know whether the Flash player always knows the dimensions of a bitmapData. Could this cause problems when not setting up the dimensions of a bitmapData? Thank you very much.