#include "TSystem.h"
#include "TCanvas.h"
#include "TH1F.h"
#include "TFormula.h"
#include "TF1.h"
#include "RQ_OBJECT.h"

TH1F *h1f;

//______________________________________________________________________________
//
//
// Helper class used to connect signal-slots.
//
//
class Spy {

   RQ_OBJECT("Spy")

public:
   Spy() { }
   ~Spy() { }

   void ProcessedEvent(Int_t event, Int_t px, Int_t py, TObject *selected);

};

//______________________________________________________________________________
void Spy::ProcessedEvent(Int_t event, Int_t px, Int_t py, TObject *selected)
{
   if (event==kKeyPress) {
      if (px==0 && py==4116) {
         printf("Next... \n");
         h1f->Reset();
         h1f->FillRandom("sqroot",10000);
         gPad->Modified();
         gPad->Update();
      }
      else if (px==0 && py==4114) {
         printf("Previous... \n");
         h1f->Reset();
         h1f->FillRandom("sqroot",10000);
         gPad->Modified();
         gPad->Update();
      }
   }
}

//______________________________________________________________________________
void testevent()
{
   Spy *spy = new Spy();
   TCanvas *c1 = new TCanvas("c1","Fitting canvas",10,10,900,700);

   TFormula *form1 = new TFormula("form1","abs(sin(x)/x)");
   TF1 *sqroot = new TF1("sqroot","x*gaus(0) + [3]*form1",0,10);
   sqroot->SetParameters(10,4,1,20);
   h1f = new TH1F("h1f","Test random numbers",200,0,10);
   h1f->SetFillColor(45);
   h1f->FillRandom("sqroot",10000);
   h1f->Draw();
   c1->Update();
   c1->Connect("ProcessedEvent(Int_t,Int_t,Int_t,TObject*)", "Spy", spy, 
               "ProcessedEvent(Int_t,Int_t,Int_t,TObject*)");
}