TCanvas *c1 = new TCanvas("c1_fit1","The Fit Canvas",200,10,700,500);
c1->SetGridx();
c1->SetGridy();
c1->GetFrame()->SetFillColor(21);
c1->GetFrame()->SetBorderMode(-1);
c1->GetFrame()->SetBorderSize(5);

gBenchmark->Start("fit1");

TString dir = gROOT->GetTutorialDir();
dir.Append("/fit/");
TFile *file = nullptr;
if (!gSystem->AccessPathName("fillrandom.root")) {
   // file exists
   file = TFile::Open("fillrandom.root");
} else {
   gROOT->ProcessLine(Form(".x %s../hist/fillrandom.C(0)",dir.Data()));
   file = TFile::Open("fillrandom.root");
   if (!file) return;
}

file->ls();

TF1 * sqroot = nullptr;
file->GetObject("sqroot",sqroot);
if (!sqroot){
   Error("fit1.C","Cannot find object sqroot of type TF1\n");
   return;
}
sqroot->Print();

TH1F* h1f = nullptr;
file->GetObject("h1f",h1f);
if (!h1f){
   Error("fit1.C","Cannot find object h1f of type TH1F\n");
   return;
}
h1f->SetFillColor(45);
h1f->Fit("sqroot");

TPaveText * fitlabel = new TPaveText(0.6,0.4,0.9,0.75,"NDC");
fitlabel->SetTextAlign(12);
fitlabel->SetFillColor(42);
fitlabel->ReadFile(Form("%sfit1_C.txt",dir.Data()));
fitlabel->Draw();
c1->Update();
gBenchmark->Show("fit1");

gROOT->GetListOfCanvases()->Draw()