#include <TH1.h>
#include <TCanvas.h>
#include <TQObject.h>

void exec3()
{
   // Example of using signal/slot in TCanvas/TPad to get feedback
   // about mouse-click events.
   //Author: Ilka Antcheva
   
   TCanvas *c1=new TCanvas("c1");

   TH2F *hpxpy  = new TH2F("hpxpy","py vs px",40,-4,4,40,-4,4);
   hpxpy->SetStats(0);
   Double_t px,py;
   for (Int_t i = 0; i < 50000; i++) {
      gRandom->Rannor(px,py);
      hpxpy->Fill(px,py);
   }
   hpxpy->Draw("col");


   c1->Update();
   c1->Connect("ProcessedEvent(Int_t,Int_t,Int_t,TObject*)", 0, 0,
               "exec3event(Int_t,Int_t,Int_t,TObject*)");
}

void exec3event(Int_t event, Int_t x, Int_t y, TObject *selected)
{
   TCanvas *c = (TCanvas *) gTQSender;

   if (event == kButton1Down) // mouse click
      printf("Canvas %s: event=%d, x=%d, y=%d, selected=%s\n", c->GetName(),
             event, x, y, selected->IsA()->GetName());
}