Getting pad width

[Viesturs]

TAttAxis::SetTitleSize() says:

Set size of axis title.

The size is expressed in per cent of the pad width

Is there a TPad method to know this width?

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[dastudillo]

GetWw()

[Viesturs]

Your answer does not seem correct.

Consider this example:

int tpadtest()
{
  TH1 * h1 = new TH1F("h", "h; x; #frac{a}{b}", 5, 0.0, 5.0);
  TH1 * h2 = new TH1F("h2", "h2; x; MC", 5, 0.0, 5.0);
  TCanvas * c = new TCanvas;
  TPad * pad1 = new TPad("pad1", "pad1", 0.0, 0.3, 1.0, 1.0);
  const unsigned int w1 = pad1 -> GetWw();
  pad1 -> Draw();
  TPad * pad2 = new TPad("pad2", "pad2", 0.0, 0.0, 1.0, 0.3);
  const unsigned int w2 = pad2 -> GetWw();
  c -> cd();
  pad2 -> Draw();
  const float labelsize = 0.2;
  h1 -> GetYaxis() -> SetLabelSize(labelsize * w2/w1);
  h2 -> GetYaxis() -> SetLabelSize(labelsize * w1/w2);
  pad1 -> cd();
  h1 -> Draw();
  pad2 -> cd();
  h2 -> Draw();
  TPad * pad3 = new TPad("pad3", "pad3", 0.2, 0.2, 1.0, 0.5);
  printf("w1 %u w2 %u w3 %u %u %u\n", pad1 -> GetWw(), pad2 -> GetWw(), pad3 -> GetWw(), w1, w2);
  return 0;
}

I try to equalise label size by taking into account differences in pad width. However, In the output I see that I have failed completely

Really, TPad::GetWv() gives the same result (698) no matter the xlow, ylow, xup, yup of the pad.

[dastudillo]

If the pad is not using the whole canvas width, you can use

pad->GetWNDC()*pad->GetWw();

etc. (similarly for height)

[Viesturs]

Does not help: pad1 -> GetWNDC() gives the same result as pad2 -> GetWNDC().

[dastudillo]

Of course, because they both go from 0 to 1 in your example.

[Viesturs]

Then how should I equalise label sizes in both pads?

[dastudillo]

The documentation for SetLabelSize says “pad size”, not “pad width”, so the issue is how the “pad size” is calculated. Trying width*height:

  float s1 = pad1->GetHNDC()*pad1->GetWNDC();
  float s2 = pad2->GetHNDC()*pad2->GetWNDC();
  h1 -> GetYaxis() -> SetLabelSize(labelsize*s2);
  h2 -> GetYaxis() -> SetLabelSize(labelsize*s1);

seems to work.

[Viesturs]

In TAxis()::SetTitleSize() it says:

The size is expressed in per cent of the pad width

Does it work the same way for both the x axis and the y axis? For example, for the x axis the pad width is relevant, while for the y axis the pad height is relevant.

[couet]

The simpler way to equalise the labels sizes among several pads is to do what is done in this example . ie: font precision 3… which means font 43 for instance