RE: text-scale-mode and switching major modes

["Drew Adams" <drew.adams@oracle.com>]

> I use noweb-mode a lot.  This mode allows to have several languages in
> one file (e.g. latex and R) and switch major modes automatically
> depending on where the cursor is -- very useful!  However, every time
> modes are switched the font size (which I set with text-scale-adjust)
> changes back to the default.  Is there a way to make the font size
> persistent?
>
> Note that I'd like to use different font sizes in
> different buffers, so setting the default font size a specific value
> is not a solution.

AFAIK, text scaling is on a per-buffer basis.  You could perhaps implement a
workaround for your problem using `(after-)change-major-mode-hook'.   

Another thing you could do, but which goes against your last sentence, is to
zoom the frame (yes, change its default font size) instead of scaling the text
of various buffers.  See http://www.emacswiki.org/emacs/SetFonts#toc6 and
http://www.emacswiki.org/emacs/download/zoom-frm.el.