gPad->GetUxmin(),GetUxmax() for 2D histogram

[Pepe_Le_Pew]

null->Range(x1-(x2-x1)*(lm/(1-rm-lm)), y1-(y2-y1)*(bm/(1-tm-bm)), x2+(x2-x1)*(rm/(1-rm-lm)), y2+(y2-y1)*(tm/(1-tm-bm)));