void palettevb()
{
/* palette */
const Int_t colnum = 10;
Int_t palette[colnum];
int i,j;
double Wcol,w1,w2,r,g,b;
TColor *color;

for (i=0;i<colnum;i++) {
  // vert -> bleu
  w1=i*0.06;
  w2=i*0.09;
  r=0.4;
  g=1-w2;
  b=0.4+w1;

  cout << "rgb :" << r << " " <<g << " " <<b <<endl;

  if (! gROOT->GetColor(500+i))
    {
      color = new TColor(500+i,r,g,b,"");
    } else {
      color = gROOT->GetColor(500+i);
      color->SetRGB(r,g,b);
    }
  palette[i] = 500+i;
}


/* palette standard */
//gStyle->SetPalette(1);


gStyle->SetPalette(colnum,palette);
gStyle->SetHistFillStyle(1001);

//gROOT->ForceStyle();

/* pour tester */
TCanvas *myc = new TCanvas("myc","myc",0,0,500,600);
myc->Divide(2,2);

ghist = new TH1F("Gaussian1","This is a gaussian",10,-10,10);
ghist2 = new TH2F("Gaussian2","This is a gaussian",10,-10,10,10,-10,10);
gRandom->SetSeed();

for (Int_t i = 0; i < 5000; i++) {
  ghist->Fill(gRandom->Gaus(0,5));
  ghist2->Fill(gRandom->Gaus(0,5),gRandom->Gaus(0,5),1);
}

color = new TColor(990, 0.8, 0.2, 0.2); 
int const top_col = 990;
//color = gROOT->GetColor(500+i);

myc->cd(1);
ghist2->Draw("colz");
myc->cd(2);
ghist->SetLineColor(502);
ghist->SetFillColor(502);
ghist->Draw();
myc->cd(3);
ghist->SetLineColor(top_col);
ghist->SetFillColor(top_col);
ghist->Draw();
myc->cd(4);
ghist->SetLineColor(509);
ghist->SetFillColor(509);
ghist->Draw();
}