/// \file

/// \ingroup tutorial_graphs

/// \notebook

/// Draw 2-Dim functions.

///

/// \macro_image

/// \macro_code

///

/// \author Rene Brun

void surfaces() {

TCanvas *c1 = new TCanvas("c1","Surfaces Drawing Options",200,10,700,900);

TPaveText *title = new TPaveText(.2,0.96,.8,.995);

title->AddText("Examples of Surface options");

title->Draw();

TPad *pad1 = new TPad("pad1","Gouraud shading",0.03,0.50,0.98,0.95);

TPad *pad2 = new TPad("pad2","Color mesh",0.03,0.02,0.98,0.48);

pad1->Draw();

pad2->Draw();

//

// We generate a 2-D function

TF2 *f2 = new TF2("f2","x**2 + y**2 - x**3 -8*x*y**4",-1,1.2,-1.5,1.5);

f2->SetContour(48);

f2->SetFillColor(45);

// Draw this function in pad1 with Gouraud shading option

pad1->cd();

pad1->SetPhi(-80);

pad1->SetLogz();

f2->Draw("surf4");

// Draw this function in pad2 with color mesh option

pad2->cd();

pad2->SetTheta(25);

pad2->SetPhi(-110);

pad2->SetLogz();

f2->SetLineWidth(1);

f2->SetLineColor(5);

f2->Draw("surf1");

//add axis titles. The titles are set on the intermediate

//histogram used for visualisation. We must force this histogram

//to be created, then force the redrawing of the two pads

pad2->Update();

f2->GetHistogram()->GetXaxis()->SetTitle("x title");

f2->GetHistogram()->GetYaxis()->SetTitle("y title");

f2->GetHistogram()->GetXaxis()->SetTitleOffset(1.4);

f2->GetHistogram()->GetYaxis()->SetTitleOffset(1.4);

pad1->Modified();

pad2->Modified();

}