is there a hook for when a buffer loses/gains the cursor or the frame loses/gains focus?

[Ted Zlatanov]

This post:

http://www.postal-code.com/binarycode/2008/05/12/save-should-die/

go me thinking that it would be nice to save every time the buffer loses
the cursor.  Is there a way in Emacs to do that?  Similarly, I'd like to
save every time the frame loses focus.  I didn't find any hooks or
functions for this.

Thanks
Ted