#include "TCanvas.h"
#include "TH2F.h"
#include "TStyle.h"

int prettyPalette(int maxPretty=500) {
  // mostly ripped from TColor.cxx
  Float_t  saturation = 1;
  Float_t  lightness = 0.5;
  Float_t  maxHue = 240;
  Float_t  minHue = 0;
  //Int_t    maxPretty = 500;
  Float_t  hue;
  Float_t r, g, b, h, l, s;
  Int_t   i;
  UInt_t g2, c;
  UInt_t nPalette = 0;
  Int_t *palette = new Int_t[maxPretty+1];
  TColor *color;
  Int_t highestIndex = 0;

  TSeqCollection *colorTable = gROOT->GetListOfColors();
  if ((color = (TColor *) colorTable->Last()) != 0) {
    if (color->GetNumber() > highestIndex) {
      highestIndex = color->GetNumber();
    }
    while ((color = (TColor *) (colorTable->Before(color))) != 0) {
      if (color->GetNumber() > highestIndex) {
	highestIndex = color->GetNumber();
      }
    }
  }
  int start = ++highestIndex;

  for (i=0 ; i<maxPretty ; i++) {
    hue = maxHue-(i+1)*((maxHue-minHue)/maxPretty);
    TColor::HLStoRGB(hue, lightness, saturation, r, g, b);
    new TColor(highestIndex, r, g, b);
    palette[nPalette] = highestIndex;
    nPalette++;
    highestIndex++;
  }

  gStyle->SetPalette(nPalette, palette);
  delete[] palette;
  return start;
}

void colors() {
  gROOT->SetStyle("Plain");
  gStyle->SetOptStat(0);
  gStyle->SetOptFit(0);
  gStyle->SetPadTickX(1);
  gStyle->SetPadTickY(1);
  gStyle->SetMarkerSize(.1);
  gStyle->SetMarkerStyle(8);
  gStyle->SetGridStyle(3);
  gStyle->SetPaperSize(TStyle::kA4);
  gStyle->SetStatW(0.25);
  gStyle->SetStatFormat("6.4g");
  gStyle->SetColorModelPS(0);

  prettyPalette();

  TSeqCollection *colorTable = gROOT->GetListOfColors();
  TColor* color = 0;
  if ((color = (TColor *) colorTable->Last()) != 0) {
    do {
      printf("color: %i hue: %f\n", color->GetNumber(), color->GetHue());
    }
    while ((color = (TColor *) (colorTable->Before(color))) != 0);
  }

  TH2F *h = new TH2F("h", "test", 50, -10, 10, 50, -10, 10);
  h->FillRandom("gaus", 10000);

  printf("z bins: %i\n", h->GetNbinsZ());

  TCanvas* cv = new TCanvas("cv", "", 1000, 1000);
  h->Draw("colz");
  cv->SaveAs("test.svg");

  delete cv;
  delete h;
}