root/html608/graphics_2gtime_8C.html

#include "TCanvas.h"
#include "TRandom3.h"
#include "TMath.h"
#include "TText.h"
#include "TArrow.h"
#include "TGraphTime.h"
#include "TROOT.h"
void gtime(Int_t nsteps = 500, Int_t np=100) {
   if (np > 1000) np = 1000;
   Int_t color[1000];
   Double_t rr[1000], phi[1000], dr[1000], size[1000];
   TRandom3 r;
   Double_t xmin = -10, xmax = 10, ymin = -10, ymax = 10;
   TGraphTime *g = new TGraphTime(nsteps,xmin,ymin,xmax,ymax);
   g->SetTitle("TGraphTime demo;X domain;Y domain");
   Int_t i,s;
   for (i=0;i<np;i++) { //calculate some object parameters
      rr[i]  = r.Uniform(0.1*xmax,0.2*xmax);
      phi[i] = r.Uniform(0,2*TMath::Pi());
      dr[i]  = r.Uniform(0,1)*0.9*xmax/Double_t(nsteps);
      Double_t rc = r.Rndm();
      color[i] = kRed;
      if (rc > 0.3) color[i] = kBlue;
      if (rc > 0.7) color[i] = kYellow;
      size[i] = r.Uniform(0.5,6);
   }
   for (s=0;s<nsteps;s++) { //fill the TGraphTime step by step
      for (i=0;i<np;i++) {
         Double_t newr = rr[i]+dr[i]*s;
         Double_t newsize = 0.2+size[i]*TMath::Abs(TMath::Sin(newr+10));
         Double_t newphi = phi[i] + 0.01*s;
         Double_t xx = newr*TMath::Cos(newphi);
         Double_t yy = newr*TMath::Sin(newphi);
         TMarker *m = new TMarker(xx,yy,20);
         m->SetMarkerColor(color[i]);
         m->SetMarkerSize(newsize);
         g->Add(m,s);
         if (i==np-1) g->Add(new TArrow(xmin,ymax,xx,yy,0.02,"-|>"), s);
      }
      g->Add(new TPaveLabel(.90,.92,.98,.97,Form("%d",s+1),"brNDC"),s);
   }
   g->Draw();
   //save object to a file
   TFile f("gtime.root","recreate");
   g->Write("g");
   //to view this object in another session do
   //  TFile f("gtime.root");
   //  g.Draw();
}