void tclread()
{
// read file generated by tclwrite
// loop on all entries.
// histogram center of lines
TFile *f = new TFile("tcl.root");
TTree *T = (TTree*)f->Get("T");
TH2F *h2 = new TH2F("h2","center of lines",40,0,1,40,0,1);
TClonesArray *arr = new TClonesArray("TLine");
T->GetBranch("tcl")->SetAutoDelete(kFALSE);
T->SetBranchAddress("tcl",&arr);
Long64_t nentries = T->GetEntries();
for (Long64_t ev=0;ev<nentries;ev++) {
arr->Clear();
T->GetEntry(ev);
Int_t nlines = arr->GetEntriesFast();
for (Int_t i=0;i<nlines;i++) {
TLine *line = (TLine*)arr->At(i);
h2->Fill(0.5*(line->GetX1()+line->GetX2()), 0.5*(line->GetY1()+line->GetY2()));
}
}
h2->Draw("lego");
}
