// ================== PlotHeights_x.C
#include <iostream>

void  gg ()
{
//  gROOT->Reset();

  //  TString datdir = "../data/";
//   TString fname = TString(filename);
//   TString file = datdir+fname;

  TCanvas *c = new TCanvas("c","test",0,0,1024,768);
  c->Divide(2,1);

  TGraph2D *dt = new TGraph2D("graph.dat");   Int_t n = dt->GetN();
  cout << "File contains " << n << " control points" << endl;

  Double_t*   x = dt->GetX();
  Double_t*   y = dt->GetY();
  Double_t*   z = dt->GetZ();
  Double_t xmax = dt->GetXmax();
  Double_t xmin = dt->GetXmin();
  Double_t ymax = dt->GetYmax();
  Double_t ymin = dt->GetYmin();

  // What the students get
  c->cd(1);
  gPad->SetPhi(-90);		// Viewpoint
  gPad->SetTheta(-89.99);
  dt->SetMarkerStyle(8);	// Marker for the control points
  dt->SetTitle("");
  dt->Draw("AP");
  c->Update();  //<==========
  
  Double_t xyz[3], uv[3];  //<==========
  TView *view = gPad->GetView();

  TText *t = new TText;
  t->SetTextSize(0.035);
  for (Int_t i=0;i<n;i++) {
    xyz[0] = dt->GetX()[i];
    xyz[1] = dt->GetY()[i];
    xyz[2] = dt->GetZ()[i];
    view->WCtoNDC(xyz,uv);
    t->DrawText(uv[0]+0.01,uv[1],Form("%g",z[i]));
  }

//   TString imagefile = "../images/"+fname+".eps";
//   gPad->Print(imagefile);	// Print the current pad (only)
  // The solution, in 3D viewed from above
  gStyle->SetPalette(1);


  Double_t contours[] = {20,40,60,80,100,120,140,160,180,200};

  c->cd(2);
  gPad->SetPhi(0);		// Viewpoint
  gPad->SetTheta(90);

  TH2D* h = dt->GetHistogram();	// Get histo interpolated between
				// control points in dt.
  h->SetContour(10,contours);		// Set 10 contour levels (default is 20)
  h->Draw("surf2");		// Draw interpolated points as surface
  h->Draw("cont1 same");	// Contour the surface
  dt->SetTitle("");
  dt->SetMarkerStyle(8);	// Marker for the control points
  dt->Draw("p same");		// Superimpose the control points

//   TString imagefile = "../images/"+fname+"_solution.eps";
//   gPad->Print(imagefile);	// Print the current pad (only)

  //return c;
}