Forcing size of a complex Flash object

As I've found recently, setting width/height properties on a Sprite only forces the Sprite to fit the given dimensions by scaling the actual size, which is开发者_StackOverflow中文版 calculated by Flash based on the rendered content.

This leaves me confused. If I have a custom Sprite subclass which draws using Graphics, how can I do layout before an initial render - the size will be zero until it is first drawn?

For a more complex issue, let's say I have a 2D game world with objects spread over a wide area with world coordinates from (0,0) to (5000,5000), where each object has a size of maybe up to 100x100. I want to have a Flash component which is the "game window", and has a fixed size like 400x300, rendering part of the game world. So how do I force the game window size to 400x300 pixels? I can draw a 400x300 rectangle to get the size correct but then if I draw any objects which are partly in-view, they can screw this up.

Is the right approach to provide a custom setSize(w,h) method which is used rather than width & height setters? But even so, is there no way to make a Sprite force to the size I want? Do you really have to catch it every render and re-scale it?

If I understand correctly, your game world is a child object of your window, and its size is always 5000x5000, but you need width and height of the window to refer only to the window itself? Use a mask, as the other comment suggests, then override the width and height getters and setters:

private var _width: Number = 400;
private var _height : Number = 300;
private var _mask : Sprite;

// some code in between

override public function get width () : Number {
    return _width;
}

override public function get height () : Number {
    return _height;
}

override public function set width ( wid:Number ) : void {
    _width = wid;
    if(_mask != null) _mask.width = wid;
}

override public function set height ( hei : Number ) : void {
    _height = hei;
    if (_mask != null) _mask.height = hei;
}

The best way to do it in my opinion is to use a mask. You have one game container where all game DisplayObjects are added to, and on top of that container you'd have a nice user interface around the game container with a mask in the center. That way the game container will only be drawn within the boundary of the mask.

Another option to force a size is to create new Sprites inside the thing you want to have width/height, placing them at the four corners. It is simple to do this with code, or via the authoring environment.