#include <TAttImage.h>

void hist2image()
{

   TCanvas *canv = new TCanvas("image", "xygaus + xygaus(5) + xylandau(10)");
   canv->ToggleEventStatus();
   canv->SetRightMargin(0.2);
   canv->SetLeftMargin(0.01);
   canv->SetTopMargin(0.01);
   canv->SetBottomMargin(0.01);

   // histogram as image (hist taken from draw2dopt.C)
   TImage *img = TImage::Create();

   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);
   TH2D *h2 = new TH2D("h2", "xygaus + xygaus(5) + xylandau(10)", 100, -4, 4, 100, -4, 4);
   h2->FillRandom("f2", 40000);
   img->SetImage((const Double_t *)h2->GetArray(), h2->GetNbinsX() + 2, h2->GetNbinsY() + 2, gHistImagePalette);
   img->Draw();
   img->StartPaletteEditor();
}