Font Sizes

ROOT
1

Root experts

I was trying to reproduce a plot that I had done in gnuplot in root.  It is pretty basic.  Three plots stacked on top of each other sharing a common x-axis.  The problem I am having is related to the font sizes.  I would like to know how to make the fonts all the same size and legible.  Right now the fonts are auto scaling.  I have used one of the examples to get started.  I have attached the current look of this plot.  The function that generates this is below.  Thanks for any input.

void generateImprovementPlot(vector<ScanResult> &results, string filename) {
  TCanvas *c1 = new TCanvas("c1","c1",200,10,700,500);

  double xlow      = 0.0;
  double xhigh     = 1.0;
  double imp_low   = 0.0;
  double imp_high  = 4.0;
  double sig_low   = 0.0;
  double sig_high  = 5.0;
  double dat_low   = 0.0;
  double dat_high  = 100000;

  TPad *pad1 = new TPad("pad1", "pad1", 0, 0.40, 1, 0.9);
  TPad *pad2 = new TPad("pad2", "pad2", 0, 0.20, 1, 0.40);
  TPad *pad3 = new TPad("pad3", "pad3", 0, 0.1, 1, 0.20);

  pad1->SetBottomMargin(0.0001);
  pad1->SetBorderMode(0);
  pad2->SetTopMargin(0.0001);
  pad2->SetBottomMargin(0.0001);
  pad2->SetBorderMode(0);
  pad3->SetTopMargin(0.0001);
  pad3->SetBottomMargin(0.1);
  pad3->SetBorderMode(0);
  pad1->Draw();
  pad2->Draw();
  pad3->Draw();

  int npoints = results.size();
  TGraphErrors *imp = new TGraphErrors(npoints);
  TGraphErrors *sig = new TGraphErrors(npoints);
  TGraphErrors *dat = new TGraphErrors(npoints);

  imp->SetTitle("");
  sig->SetTitle("");
  dat->SetTitle("");

  vector<ScanResult>::iterator it;
  int counter = 0;
  for(it = results.begin(); it != results.end(); it++) {
    ScanResult tmp = (*it);

    if(tmp.data_events != 0) xhigh = tmp.cutpoint;

    imp->SetPoint(counter, tmp.cutpoint, tmp.improvement);
    imp->SetPointError(counter, 0, tmp.improvement_err);

    double imphigh = tmp.improvement + tmp.improvement_err;
    double implow  = tmp.improvement - tmp.improvement_err;
    if(imphigh > imp_high) imp_high = imphigh;
    if(implow < imp_low) imp_low = implow;

    sig->SetPoint(counter, tmp.cutpoint, tmp.signal_pred_events);
    sig->SetPointError(counter, 0, 0);

    if(tmp.signal_pred_events > sig_high) sig_high = tmp.signal_pred_events;
    if(tmp.signal_pred_events < sig_low) sig_low = tmp.signal_pred_events;

    dat->SetPoint(counter, tmp.cutpoint, tmp.data_events);
    dat->SetPointError(counter, 0, 0);

    if(tmp.data_events > dat_high) dat_high = tmp.data_events;
    if(tmp.data_events < dat_low) dat_low = tmp.data_events;

    counter++;
  }

  double imp_delta = imp_high - imp_low / 8.0;
  imp_high += imp_delta;
  imp_low  -= imp_delta;

  double sig_delta = sig_high - sig_low / 8.0;
  sig_high += sig_delta;
  sig_low  -= sig_delta;

  double dat_delta = dat_high - dat_low / 8.0;
  dat_high += dat_delta;
  dat_low  -= dat_delta;

  pad1->cd();
  imp->Draw("AP*");
  imp->GetHistogram()->GetYaxis()->SetTitle("Improvement");

  pad2->cd();
  sig->Draw("AP*");
  sig->GetHistogram()->GetYaxis()->SetTitle("Signal Events");

  pad3->cd();
  dat->Draw("AP*");
  dat->GetHistogram()->GetXaxis()->SetTitle("Decision Tree Discriminant");
  dat->GetHistogram()->GetYaxis()->SetTitle("Data Events");

  c1->cd();

  TText *thetitle = new TText;
  thetitle->SetTextAlign(22);
  thetitle->DrawTextNDC(0.5, 0.95, "S/#sqrt{B} Improvement Search");

  c1->SaveAs("test.eps");
}

Justace

2

Specify text font to be hardware and size in pixels,

eg

imp->GetHistogram()->GetYaxis()->SetTextFont(63); imp->GetHistogram()->GetYaxis()->SetTextSize(12); //12 pixels size
see : root.cern.ch/root/html/TAttText.html

Rene

3

Those methods do not exist for the TAxis.

4

Ok, I think that I got that handled. I just used the global TStyle object. There is at least one other thing that bothers me about this plot and that is the size of the tick marks. They are all different lengths between the different histos and I would like to remove the minor ticks. I looked at the SetTickLength(float) method and saw that it sets a relative length. Is there a way to specify a fixed length? Without resorting to hand drawing the ticks? I have attached a plot showing what I am speaking about.

Justace

test.gif696×472 7.04 KB

5

See this example:

{ 
   TH1F* h1 = new TH1F ("h1", "h1", 100, 0, 1);
   h1->FillRandom("gaus");   
   TH1F* h2 = new TH1F ("h2", "h2", 100, -1, 0);
   h2->FillRandom("gaus");
   TCanvas *c = new TCanvas("c","c",600,400);
   c->Draw();
   TPad *p1 = new TPad("p1","p1",0.1,0.3,0.9,0.9);
   p1->Draw();
   TPad *p2 = new TPad("p2","p2",0.1,0.1,0.9,0.3);
   p2->Draw();
   p1->cd();
   h1->Draw(); 
   h1->GetYaxis()->SetNdivisions(5); 
   p2->cd();
   h2->Draw(); 
   h2->GetYaxis()->SetNdivisions(5);
}