TPave coordinates

Is there a way to draw a TPave on a function or histogram plot specifying the size/position in units other than ones based on the function or histogram axis scales?

In other words, let’s say I want a TPave in the upper right corner, about 1/3 the height and 1/3 the width of the plot, independent of what the horizontal and vertical axis scales are, whether they’re logarithmic or not, and so on. What’s the easiest way to do that? I’ve looked in the examples but can’t find anything that addresses this.

see documentation of TPave constructor: root.cern.ch/root/htmldoc/TPave.html#TPave:TPave

TPave p(0.33,0.33,0.55,0.44,4,"brNDC"); p.Draw();
Rene