Issue with TGraphPolar: Unable to change title size or borders

Newbie
1

Hi everyone,
I’m creating a polar plot using TGraphPolar in ROOT, but I’m having an issue with the title. No matter what I do, the title always appears stuck at π/2 and I can’t move it or change its size.
I checked several examples online, and it looks like everyone has the same problem. :sweat_smile:
Does anyone know if there’s a proper way to modify the position or size of the title in TGraphPolar?
Thanks in advance!

Captura desde 2025-03-12 21-34-54
Captura desde 2025-03-12 21-34-54802×642 29.8 KB

 graph2->SetTitle("Graph Angular");
    graph2->SetLineWidth(2); 
    graph2->SetLineColor(kRed); 
    graph2->Draw("AL");
    c2->Draw();
    c2->Update();

ROOT Version: 6.28/04
Platform: Ubuntu
Compiler: GCC

2

You can change all the lines widths with:

   gre->SetLineWidth(2);

if gre is a TGgraph drawn with POL option.
Can you provide a small running example showing your point ?

3

I didn’t find an obvious way to manipulate the title through the graph itself, but you can access the title box after you draw the graph:

TGraphPolar gr;
gr.SetPoint(0, 1, 2);
gr.SetTitle("123");
gr.Draw("LP");
auto title = ((TPaveText*)gPad->FindObject("title"));
title->SetX1(0.6);
title->SetX2(0.9);
gPad->Draw();

Alternatively, you can draw and drag the title with the mouse.

image
image690×472 55.6 KB

4

Try with gStyle->SetTitleX(0.75); (test numbers from 0 to 1); similarly for y.

5

Good idea, that works, too! Just note that this will move the titles for all plots.

1 Like