[quote]Instead of that, one has to go and look into Root source code to know how to proceed,
which is time-consuming and tiresome.[/quote]Still the case… 
Now that “redirect” methods exist (see [url]Locate like command why not reconsider this point and add the 2 following insignificant lines in TPad.h
Double_t GetXupNDC() const {return (fXlowNDC+fWNDC);}
Double_t GetYupNDC() const {return (fYlowNDC+fHNDC);}
I still don’t have better arguments than consistency & end user easy/intuitive experience.
Note this was one of the statement in Fons’s last presentation (http://indico.cern.ch/conferenceDisplay.py?confId=255905)
[quote]Improve end user graphics experience[/quote]Cheers,
Z