I’m looking to draw a horizontal line in a sub-pad (created with TCanvas::Divide()), going from the X axis minimum value to its max value:
TGraphErrors *magres = new TGraphErrors(mlig, mjd, mmag, mjde, merr); TCanvas *c1 = new TCanvas("c1","",0,0,700,900); c1->Divide(1,4); [...] c1->cd(2); magres->Draw("AP"); double xmin = gPad->GetUxmin(); double xmax = gPad->GetUxmax(); TLine *zero = new TLine(xmin, 0, xmax, 0); zero->Draw(); [...]
But, xmin = 0, xmax = 1, instead of ~80 and ~170 respectively.
I suspect that gPad refers not to the current subpad but to the global Pad?
If so, how to get the user coordinates of a sub-pad window?
Many thanks for any help!