change style based on file, and another q

[Rich E]

Hi,

Is there a way to make doxymacs change styles depending on what file I am visiting?  For instance, switch to Qt when in a C file, and C++ when in a C++ file..

Also, I cannot find what the documentation is stating here:

Customise the variables doxymacs-doxygen-root and doxymacs-doxygen-tags. You can customise these via the customisation menu Programming | Tools | Doxymacs.

I cannot find doxymacs-doxygen-root or doxymacs-doxygen-tags anywhere within emacs.

thanks if you can help,
rich