hist043_Graphics_highlight.C File Reference

Detailed Description

This tutorial demonstrates how the highlight mechanism can be used on an histogram.

A 2D histogram is booked an filled with a random gaussian distribution. Then an highlight method is connected to the histogram. Moving the mouse on the histogram will update the histogram title in real time according to the highlighted bin.

 
TText *info = nullptr;
 
void HighlightTitle(TVirtualPad *pad, TObject *obj, Int_t xhb, Int_t yhb)
{
   auto h2 = dynamic_cast<TH2F *>(obj);
   if (!h2)
      return;
   if (!h2->IsHighlight()) { // after highlight disabled
      h2->SetTitle("Disable highlight");
      return;
   }
   if (info)
      info->SetTitle("");
   TString t;
   t.Form("bin[%02d, %02d] (%5.2f, %5.2f) content %g", xhb, yhb, h2->GetXaxis()->GetBinCenter(xhb),
          h2->GetYaxis()->GetBinCenter(yhb), h2->GetBinContent(xhb, yhb));
   h2->SetTitle(t.Data());
   pad->Update();
}
 
void hist043_Graphics_highlight()
{
   auto c1 = new TCanvas();
   c1->HighlightConnect("HighlightTitle(TVirtualPad*,TObject*,Int_t,Int_t)");
 
   auto h2 = new TH2F("h2", "", 50, -5.0, 5.0, 50, -5.0, 5.0);
   for (Int_t i = 0; i < 10000; i++)
      h2->Fill(gRandom->Gaus(), gRandom->Gaus());
   h2->Draw();
 
   info = new TText(0.0, -4.0, "please move the mouse over the frame");
   info->SetTextAlign(22);
   info->SetTextColor(kRed + 1);
   info->SetBit(kCannotPick);
   info->Draw();
   c1->Update();
 
   // call after update to apply changes in the histogram painter
   h2->SetHighlight();
}

Date

March 2018

Author

Jan Musinsky

Definition in file hist043_Graphics_highlight.C.