//Draw color plots using different color palettes.
//Author:: Olivier Couet

#include "TStyle.h"
#include "TColor.h"
#include "TF2.h"
#include "TExec.h"
#include "TCanvas.h"

   
void Pal1()
{
   static Int_t  colors[50];
   static Bool_t initialized = kFALSE;

   Double_t Red[3]    = { 1.00, 0.00, 0.00};
   Double_t Green[3]  = { 0.00, 1.00, 0.00};
   Double_t Blue[3]   = { 1.00, 0.00, 1.00};
   Double_t Length[3] = { 0.00, 0.50, 1.00 };

   if(!initialized){
      Int_t FI = TColor::CreateGradientColorTable(3,Length,Red,Green,Blue,50);
      for (int i=0; i<50; i++) colors[i] = FI+i;
      initialized = kTRUE;
      return;
   }
   gStyle->SetPalette(50,colors);
}

void Pal2()
{
   static Int_t  colors[50];
   static Bool_t initialized = kFALSE;

   Double_t Red[3]    = { 1.00, 0.50, 0.00};
   Double_t Green[3]  = { 0.50, 0.00, 1.00};
   Double_t Blue[3]   = { 1.00, 0.00, 0.50};
   Double_t Length[3] = { 0.00, 0.50, 1.00 };

   if(!initialized){
      Int_t FI = TColor::CreateGradientColorTable(3,Length,Red,Green,Blue,50);
      for (int i=0; i<50; i++) colors[i] = FI+i;
      initialized = kTRUE;
      return;
   }
   gStyle->SetPalette(50,colors);
}

TCanvas* multipalette() {
   TCanvas *c3  = new TCanvas("c3","C3",0,0,600,400);
   c3->Divide(2,1);
   TF2 *f3 = new TF2("f3","0.1+(1-(x-2)*(x-2))*(1-(y-2)*(y-2))",1,3,1,3);


   c3->cd(1);
   f3->Draw("surf1"); 
   TExec *ex1 = new TExec("ex1","Pal1();");
   ex1->Draw();
   f3->Draw("surf1 same"); 

   c3->cd(2);
   f3->Draw("surf1"); 
   TExec *ex2 = new TExec("ex2","Pal2();");
   ex2->Draw();
   f3->Draw("surf1 same"); 

   return c3;
}