Just made a quick example .capx
This is basically how I would scale up and down.
The thing you have to do on your project is to get the math right on the scale factor. It depends on the viewrange(in LOS) of your player and the original size of the view vindow(which is scale 1).
I have tried to illustrate it:
<img src="https://dl.dropboxusercontent.com/u/2560922/mobiledev/forum/lineOfSightScaleLayout.png" border="0">
Hope it helped a bit.