// example.C
#include  <TGClient.h>
#include  <TCanvas.h>
#include  <TF1.h>
#include  <TRandom.h>
#include  <TGButton.h>
#include  <TGFrame.h>
#include  <TRootEmbeddedCanvas.h>
#include  <RQ_OBJECT.h>
class MyMainFrame {
    RQ_OBJECT("MyMainFrame")
private:
   TGMainFrame         *fMain;
   TRootEmbeddedCanvas *fEcanvas;
public:
   MyMainFrame(const TGWindow *p,UInt_t w,UInt_t h);
   virtual ~MyMainFrame();
   void DoDraw();
};

MyMainFrame::MyMainFrame(const TGWindow *p,UInt_t w,UInt_t h) {
  // Create a main frame
  fMain = new TGMainFrame(p,w,h);
  // Create canvas widget
  fEcanvas = new TRootEmbeddedCanvas("Ecanvas",fMain,200,200);
  fMain->AddFrame(fEcanvas, new TGLayoutHints(kLHintsExpandX| kLHintsExpandY,
                                               10,10,10,1));
  // Create a horizontal frame widget with buttons
  TGHorizontalFrame *hframe = new TGHorizontalFrame(fMain,200,40);
  TGTextButton *draw = new TGTextButton(hframe,"&Draw");
  draw->Connect("Clicked()","MyMainFrame",this,"DoDraw()");
  hframe->AddFrame(draw, new TGLayoutHints(kLHintsCenterX,5,5,3,4));
  TGTextButton *exit = new TGTextButton(hframe,"&Exit",
                                        "gApplication->Terminate(0)");
  hframe->AddFrame(exit, new TGLayoutHints(kLHintsCenterX,5,5,3,4));
  fMain->AddFrame(hframe, new TGLayoutHints(kLHintsCenterX,2,2,2,2));
  // Set a name to the main frame
  fMain->SetWindowName("Simple Example");
  // Map all subwindows of main frame
  fMain->MapSubwindows();
  // Initialize the layout algorithm
  fMain->Resize(fMain->GetDefaultSize());
  // Map main frame
  fMain->MapWindow();
}
void MyMainFrame::DoDraw() {
  // Draws function graphics in randomly choosen interval
  TF1 *f1 = new TF1("f1","sin(x)/x",0,gRandom->Rndm()*10);
  f1->SetFillColor(19);
  f1->SetFillStyle(1);
  f1->SetLineWidth(3);
  f1->Draw();
  TCanvas *fCanvas = fEcanvas->GetCanvas();
  fCanvas->cd();
  fCanvas->Update();
}
MyMainFrame::~MyMainFrame() {
  // Clean up used widgets: frames, buttons, layouthints
  fMain->Cleanup();
  delete fMain;
}
void example() {
  // Popup the GUI...
  new MyMainFrame(gClient->GetRoot(),200,200);
}