void hist020_TH2_draw()
{
   gStyle->SetOptStat(0);
   gStyle->SetCanvasColor(33);
   gStyle->SetFrameFillColor(18);
   TF2 *f2 = new TF2("f2", "xygaus + xygaus(5) + xylandau(10)", -4, 4, -4, 4);
   Double_t params[] = {130, -1.4, 1.8, 1.5, 1, 150, 2, 0.5, -2, 0.5, 3600, -2, 0.7, -3, 0.3};
   f2->SetParameters(params);
   auto h2 = new TH2F("h2", "xygaus + xygaus(5) + xylandau(10)", 20, -4, 4, 20, -4, 4);
   h2->SetFillColor(46);
   h2->FillRandom("f2", 40000);
   TPaveLabel pl;

   // basic 2-d options
   Float_t xMin = 0.67, yMin = 0.875, xMax = 0.85, yMax = 0.95;
   Int_t cancolor = 17;
   auto c2h = new TCanvas("c2h", "2-d options", 10, 10, 800, 600);
   c2h->Divide(2, 2);
   c2h->SetFillColor(cancolor);
   c2h->cd(1);
   h2->Draw();
   pl.DrawPaveLabel(xMin, yMin, xMax, yMax, "SCAT", "brNDC");
   c2h->cd(2);
   h2->Draw("box");
   pl.DrawPaveLabel(xMin, yMin, xMax, yMax, "BOX", "brNDC");
   c2h->cd(3);
   h2->Draw("arr");
   pl.DrawPaveLabel(xMin, yMin, xMax, yMax, "ARR", "brNDC");
   c2h->cd(4);
   h2->Draw("colz");
   pl.DrawPaveLabel(xMin, yMin, xMax, yMax, "COLZ", "brNDC");
   c2h->Update();

   // text option
   auto ctext = new TCanvas("ctext", "text option", 50, 50, 800, 600);
   gPad->SetGrid();
   ctext->SetFillColor(cancolor);
   ctext->SetGrid();
   h2->Draw("text");
   pl.DrawPaveLabel(xMin, yMin, xMax, yMax, "TEXT", "brNDC");
   ctext->Update();

   // contour options
   auto cont = new TCanvas("contours", "contours", 100, 100, 800, 600);
   cont->Divide(2, 2);
   gPad->SetGrid();
   cont->SetFillColor(cancolor);
   cont->cd(1);
   h2->Draw("contz");
   pl.DrawPaveLabel(xMin, yMin, xMax, yMax, "CONTZ", "brNDC");
   cont->cd(2);
   gPad->SetGrid();
   h2->Draw("cont1");
   pl.DrawPaveLabel(xMin, yMin, xMax, yMax, "CONT1", "brNDC");
   cont->cd(3);
   gPad->SetGrid();
   h2->Draw("cont2");
   pl.DrawPaveLabel(xMin, yMin, xMax, yMax, "CONT2", "brNDC");
   cont->cd(4);
   gPad->SetGrid();
   h2->Draw("cont3");
   pl.DrawPaveLabel(xMin, yMin, xMax, yMax, "CONT3", "brNDC");
   cont->Update();

   // lego options
   auto lego = new TCanvas("lego", "lego options", 150, 150, 800, 600);
   lego->Divide(2, 2);
   lego->SetFillColor(cancolor);
   lego->cd(1);
   h2->Draw("lego");
   pl.DrawPaveLabel(xMin, yMin, xMax, yMax, "LEGO", "brNDC");
   lego->cd(2);
   h2->Draw("lego1");
   pl.DrawPaveLabel(xMin, yMin, xMax, yMax, "LEGO1", "brNDC");
   lego->cd(3);
   gPad->SetTheta(61);
   gPad->SetPhi(-82);
   h2->Draw("surf1pol");
   pl.DrawPaveLabel(xMin, yMin, xMax + 0.05, yMax, "SURF1POL", "brNDC");
   lego->cd(4);
   gPad->SetTheta(21);
   gPad->SetPhi(-90);
   h2->Draw("surf1cyl");
   pl.DrawPaveLabel(xMin, yMin, xMax + 0.05, yMax, "SURF1CYL", "brNDC");
   lego->Update();

   // surface options
   auto surf = new TCanvas("surfopt", "surface options", 200, 200, 800, 600);
   surf->Divide(2, 2);
   surf->SetFillColor(cancolor);
   surf->cd(1);
   h2->Draw("surf1");
   pl.DrawPaveLabel(xMin, yMin, xMax, yMax, "SURF1", "brNDC");
   surf->cd(2);
   h2->Draw("surf2z");
   pl.DrawPaveLabel(xMin, yMin, xMax, yMax, "SURF2Z", "brNDC");
   surf->cd(3);
   h2->Draw("surf3");
   pl.DrawPaveLabel(xMin, yMin, xMax, yMax, "SURF3", "brNDC");
   surf->cd(4);
   h2->Draw("surf4");
   pl.DrawPaveLabel(xMin, yMin, xMax, yMax, "SURF4", "brNDC");
   surf->Update();
}