You cannot subclass QPrinter. At most you can subclass QPrintEngine, but there's little you can do with it.

A tedious solution is to take pdf support from Qt( from QPrinter ) and make your own class
of PDF Export.

Also, if all you want si save some text, you can make you're own PDF Export ( not based on QPrinter ). Just take the text from the QTextEdiot and saver it in pdf. It isn't that hard to add a few fonts to the page resources and text to the content stream.

Regards