#include "TFile.h"
#include "TCanvas.h"
#include "TStyle.h"
#include "TH1.h"
#include "TH2.h"
#include "TH3.h"
#include "TGaxis.h"
#include "TRandom.h"
#include "TLegend.h"
#include "TPaveStats.h"
#include "TGraph.h"

void test()
{
   TFile *f = TFile::Open("H:/cors/cors_plot.root");
   if (f == 0) {
      // if we cannot open the file, print an error message and return immediatly
      printf("Error: cannot open cors_plot.root!\n");
      return;
   }
   f->ls();
   gStyle->SetOptFit();
   TCanvas *c36 = new TCanvas("c36","multigraph",1024,748);
   //c36->SetGrid();
   gStyle->SetOptFit(0001);

   // draw a frame to define the range
   TMultiGraph *mg = new TMultiGraph();
   TGraphErrors *gr1 = new TGraphErrors("H:/cors/dati4.txt","%lg %*lg %lg %*lg %*lg %*lg %*lg %*lg %*lg %*lg");
   gr1->SetMarkerColor(kBlue);
   gr1->SetMarkerStyle(21);
   TF1 *fit1 = new TF1("fit1", "[0]*x+[1]", 1, 5e3);
   fit1->SetParameters(-1e-6, -2e-3);
   fit1->SetParName(0,"m");
   fit1->SetParName(1,"q");
   fit1->SetLineColor(kYellow);
   gr1->Fit("fit1","q");
   //gr1->Fit("pol1","q");
   mg->Add(gr1);

   // create second graph
   TGraphErrors *gr2 = new TGraphErrors("H:/cors/dati4.txt","%lg %*lg %*lg %lg %*lg %*lg %*lg %*lg %*lg %*lg");
   gr2->SetMarkerColor(kRed);
   gr2->SetMarkerStyle(20);
   TF1 *fit2 = new TF1("fit2", "[0]*x+[1]", 1, 5e3);
   fit2->SetParameters(4.4e-6, -2e-4);
   fit2->SetParName(0,"m");
   fit2->SetParName(1,"q");
   fit2->SetLineColor(kGreen);
   gr2->Fit("fit2","q");
   // gr2->Fit("pol1","q");

   mg->Add(gr2);
   mg->Draw("ap");

//force drawing of canvas to generate the fit TPaveStats
   mg->SetTitle("Energia primario- densita'");
   mg->GetXaxis()->SetTitle("Energia (GeV)");
   mg->GetYaxis()->SetTitle("Densita'(particelle/m^2)");
    gPad->Modified();
   //force drawing of canvas to generate the fit TPaveStats
   c36->Update();
   TLegend* leg = new TLegend(0.2, 0.7, .4, .85);
   leg->SetNColumns(1);
   leg->AddEntry(gr1, "distanza 10 m", "lp");
   leg->AddEntry(fit1, "distanza 10 m Fit", "l");
   leg->AddEntry(gr2, "distanza 100 m", "lp");
   leg->AddEntry(fit2, "distanza 100 m Fit", "l");
   leg->Draw("same");
   TPaveStats *stats1 = (TPaveStats*)gr1->GetListOfFunctions()->FindObject("stats");
   TPaveStats *stats2 = (TPaveStats*)gr2->GetListOfFunctions()->FindObject("stats");
   if (stats1) {
      stats1->SetTextColor(kBlue);
      stats1->SetX1NDC(0.12); stats1->SetX2NDC(0.32); stats1->SetY1NDC(0.75);
   }
   if (stats2) {
      stats2->SetTextColor(kRed);
      stats2->SetX1NDC(0.72); stats2->SetX2NDC(0.92); stats2->SetY1NDC(0.78);
   }
  
   c36->Modified();
 //  gROOT->ProcessLine("gROOT->SetBatch()");
 //  c32.Print("H:/cors/distr_lat_adroni_energia.pdf");delete c32;
  // gROOT->ProcessLine("gROOT->SetBatch(kFALSE)");
}