/// \file
/// \ingroup tutorial_hist
/// \notebook
/// \preview The legend can be placed automatically in the current pad in an empty space
/// found at painting time.
///
/// The following example illustrate this facility. Only the width and height of the
/// legend is specified in percentage of the pad size.
///
/// \macro_image
/// \macro_code
///
/// \date November 2024
/// \author Olivier Couet

void hist011_TH1_legend_autoplaced()
{
   auto *c4 = new TCanvas("c", "c", 600, 500);

   // Create a dummy histogram
   auto *hpx = new TH1D("hpx", "This is the hpx distribution", 100, -4., 4.);
   hpx->FillRandom("gaus", 50000);
   hpx->Draw("E");
   hpx->GetYaxis()->SetTitle("Y Axis title");
   hpx->GetYaxis()->SetTitleOffset(1.3);
   hpx->GetYaxis()->CenterTitle(true);
   hpx->GetXaxis()->SetTitle("X Axis title");
   hpx->GetXaxis()->CenterTitle(true);

   // Create another dummy histogram
   auto *h1 = new TH1D("h1", "A green histogram", 100, -2., 2.);
   h1->FillRandom("gaus", 10000);
   h1->SetLineColor(kGreen);
   h1->Draw("same");

   // Create a dummy graph
   auto *g = new TGraph();
   g->SetPoint(0, -3.5, 100);
   g->SetPoint(1, -3.0, 300);
   g->SetPoint(2, -2.0, 1000);
   g->SetPoint(3, 1.0, 800);
   g->SetPoint(4, 0.0, 200);
   g->SetPoint(5, 3.0, 200);
   g->SetPoint(6, 3.0, 700);
   g->Draw("L");
   g->SetTitle("This is a TGraph");
   g->SetLineColor(kRed);
   g->SetFillColor(0);

   // TPad::BuildLegend() default placement values are such that they trigger
   // the automatic placement.
   c4->BuildLegend();
}
