Resize Composition to Layers Scale

Question

Hi AEScripters,
could someone tell me why my script doesen't center all my layers?
(I'm trying to build a tiny crop tool)
thnx a lot
:F
Here is my code:
// written by fabiantheblind
// http://www.the-moron.net
function fitCompToLayer()
app.beginUndoGroup("fit Comp To Layer");
var activeComp = app.project.activeItem;
var selection = app.project.activeItem.selectedLayers[0];
var myScale = selection.scale.valueAtTime(0.0,false);
var myScaleW = myScale[0];
var myScaleH = myScale[1];
activeComp.width  = Math.floor((activeComp.width/100)*myScaleW);
activeComp.height = Math.floor((activeComp.height/100)*myScaleH);
// this doesn't work. but why?
var newWidth = app.project.activeItem.width;
var newHeight = app.project.activeItem.height;
var myLayers = activeComp.layers;
for(var i = 1; i< myLayers.length;i++){
myLayers[i].position[0] =   newWidth / 2;
     myLayers[i].position[1] =   newHeight / 2;
app.endUndoGroup();
fitCompToLayer();

Answer 1

haha. Or you make this the easy way like this:
To crop the composition to the region of interest, choose Composition > Crop Comp To Region Of Interest.
http://help.adobe.com/en_US/aftereffects/cs/using/WS3878526689cb91655866c1103906c6dea-7f05 a.html