gtime2.C

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/// \file
/// \ingroup tutorial_graphs
/// \notebook
/// Example of TGraphTime showing how the class could be used to visualize
/// a set of particles with their time stamp in a MonteCarlo program.
///
/// \macro_image
/// \macro_code
///
/// \author Rene Brun
 
#include "TRandom3.h"
#include "TMath.h"
#include "TMarker.h"
#include "TPaveLabel.h"
#include "TArrow.h"
#include "TGraphTime.h"
#include <vector>
 
void gtime2(Int_t nsteps = 200, Int_t np = 5000)
{
   if (np > 5000)
      np = 5000;
   std::vector<Int_t> color(np);
   std::vector<Double_t> cosphi(np), sinphi(np), speed(np);
   TRandom3 r;
   Double_t xmin = 0, xmax = 10, ymin = -10, ymax = 10;
   TGraphTime *g = new TGraphTime(nsteps, xmin, ymin, xmax, ymax);
   g->SetTitle("TGraphTime demo 2;X;Y");
   Double_t fact = xmax / Double_t(nsteps);
   for (Int_t i = 0; i < np; i++) { // calculate some object parameters
      speed[i] = r.Uniform(0.5, 1);
      Double_t phi = r.Gaus(0, TMath::Pi() / 6.);
      cosphi[i] = fact * speed[i] * TMath::Cos(phi);
      sinphi[i] = fact * speed[i] * TMath::Sin(phi);
      Double_t rc = r.Rndm();
      color[i] = kRed;
      if (rc > 0.3)
         color[i] = kBlue;
      if (rc > 0.7)
         color[i] = kYellow;
   }
   for (Int_t s = 0; s < nsteps; s++) { // fill the TGraphTime step by step
      for (Int_t i = 0; i < np; i++) {
         Double_t xx = s * cosphi[i];
         if (xx < xmin)
            continue;
         Double_t yy = s * sinphi[i];
         TMarker *m = new TMarker(xx, yy, 25);
         m->SetMarkerColor(color[i]);
         m->SetMarkerSize(1.5 - s / (speed[i] * nsteps));
         g->Add(m, s);
      }
      g->Add(new TPaveLabel(.70, .92, .98, .99, TString::Format("shower at %5.3f nsec", 3. * s / nsteps), "brNDC"), s);
   }
 
   g->Draw();
 
   // store object as animated gif
   // g->SaveAnimatedGif("gtime2.gif");
 
   // start animation, can be stopped with g->Animate(kFALSE);
   // g->Animate();
}