Solid changes with Text

[TheFrockingSN]

Hi There,

I'm trying to make my solid layer automatically change at the correct height and width when changing the text without expressing the scale. (It is going to be animated in).

Example:

You can see the solid just stays in his position. I know there is an simple expression for it. Could somebody please explain how this is done?

I know there is a video explaining this but I still can't get it figure out. The video I mean is: 16 Useful Expressions in After Effects - Part 1 of 2 - YouTube

It starts at: 09:10 it only shows the width but I need both aspect with a self made ratio and not completely stuck to the text. (like his lower third that comes after that part)

Thanks

[Mylenium]

That's what sourceRectAtTime() is for. Look it up in the help or a web search.

Mylenium

[TheFrockingSN]

What am I doing wrong?!