Sometimes the axis range can not be defined by users?

[newconcept1979]

i want to change the X axis range using the code below:

hist2->GetXaxis()->SetRangeUser(1.e-2,20000.);

but it does not work well，like the figure below:

why the code does not work?

---

Please read tips for efficient and successful posting and posting code

ROOT Version: 6.24/04
Platform: Ubuntu 20.04
Compiler: GCC 9.3.0

---

[dastudillo]

Try this

Changing x-axis of TGraph

To go outside the existing data points (or bins), use SetLimits; to ‘zoom in’ within the limits, use SetRangeUser (for axis values) or SetRange (for bin numbers); in all cases, first you get the axis. For your example: gt->GetXaxis()->SetLimits(1, 20);

[couet]

It works for me wiith this small example:

void rangeuser(){
   auto C = new TCanvas();
   auto h = new TH1F("h","h",100,1,1000000);
   C->SetLogx();
   h->GetXaxis()->SetRangeUser(1,1000);
   h->Draw();
}

[dastudillo]

I think the issue is that they want the plot to go beyond the maximum x bin of hist2 (20000 vs 20). SetRangeUser does not “extend” the x-axis beyond the histogram bins, but SetLimits works.