How to cover the whole Composite with scale property?

[Dan Ebberts]

This should get you close:

startScale = 1; //time when scaling starts (seconds)
scaleDur = 2; // scale duratation (seconds)
initScale = [100,100]; // initial scale value

w = thisComp.width*thisComp.pixelAspect;
h = thisComp.height;
finalScale = [w/(width*source.pixelAspect),h/height]*100
ease(time,startScale,startScale+scaleDur,initScale,finalScale)

If you’re doing this from the upper-left corner, you’ll probably want to move the anchor point to the upper left corner of your layer.

Dan