Bulletproof way to do resolution independant GUI scaling?

An alternative way to scale GUI elements automatically is to add this snippet of code to the top of all of your OnGUI() functions, and then create your boxes in native resolution pixel numbers. The GUI.matrix setup below will scale everything to look the same on all machines

 var native_width : float = 1920;
 var native_height : float = 1080;
 
 function OnGUI ()
 {
     //set up scaling
     var rx : float = Screen.width / native_width;
     var ry : float = Screen.height / native_height;
     GUI.matrix = Matrix4x4.TRS (Vector3(0, 0, 0), Quaternion.identity, Vector3 (rx, ry, 1)); 
 
     //now create your GUI normally, as if you were in your native resolution
     //The GUI.matrix will scale everything automatically.

     //example
     GUI.Box(  Rect(810, 490, 300, 100)  , "Hello World!");
 
 }

Normally I'm against handing out free code like this, but GUI.matrix is complex {think 200-level college Math course complex} and it took me about 15 minutes of searching to find.