I'm trying to define an emacs function that will be called when the display size changes, currently I'm not finding any hooks that I can use for this.

I an NOT trying to notice when the emacs window changes size.

My use case is that I have emacs open on my laptop, then I close it and bring it to work and plug it into a bigger monitor and turn it on via the keyboard. After logging in my windows are all in the top left corner.

I want emacs to notice the screen size change and call my function allow me to reposition the window and change the font size.

yes, I know about stay but I also want to change the font size.

I'm running emacs 24.3.1 from emacsformacosx.com under OSX Mavericks