Добавление кнопки gtkmm

#ifndef GTKMM_EXAMPLE_MYAREA_H
#define GTKMM_EXAMPLE_MYAREA_H
 
 
#include <gtkmm.h>
 
class MyArea : public Gtk::DrawingArea
{
public:
  MyArea();
  virtual ~MyArea();
 
protected:
  //Override default signal handler:
  virtual bool on_draw(const Cairo::RefPtr<Cairo::Context>& cr);
};
class Points;
 
Points get_array(Points *);
 
class Points
{
public:
    int *x,*y,n;
    Points();
    Points(int);
    Points(int,int*,int*);
    void set_x(int,int);
    void set_y(int,int);
    int get_x(int);
    int get_y(int);
    int get_n();
 
    ~Points();
 
    /* data */
};
 
#endif // GTKMM_EXAMPLE_MYAREA_H

#include "myarea.h"
#include <cairomm/context.h>
#include <iostream>
#include <stdio.h>
#include <stdlib.h>
 
using namespace std;
 
Points* get_array()
{
  FILE *fp=fopen ("Point.txt", "r");
  int n;
  fscanf(fp, "%i", &n);
  int *x = new int [n]; 
  int *y = new int [n];
  for (int i = 0; i < n; i++)
  {
    fscanf(fp, "%i%i", &x[i], &y[i]); 
  }
  return (new Points(n, x, y));
}
 
 
MyArea::MyArea()
{
}
MyArea::~MyArea()
{
}
bool MyArea::on_draw(const Cairo::RefPtr<Cairo::Context>& cr)
{
  Gtk::Allocation allocation = get_allocation();
  const int width = allocation.get_width();
  const int height = allocation.get_height();
 
  // coordinates for the center of the window
  int xc, yc;
  xc = width / 2;
  yc = height / 2;
 
  cr->set_line_width(3.0);
 
  // draw red lines out from the center of the window
  cr->set_source_rgb(0.8, 0.0, 0.0);
  Points *T = get_array();
  cr->move_to(T->get_x(0),T->get_y(0));
  
  
  for (int i = 0; i <  T->get_n() ; ++i)
  {
    cr->line_to(T->get_x(i),T->get_y(i) );  
  }
  cr->line_to(T->get_x(0),T->get_y(0) );
  
 
  cr->stroke();
 
  return true;
}
 
//-----Points
  Points::Points()
  {
    n=0;
    x=NULL;
    y=NULL;
  }
  Points::Points(int nn)
  {
    n=nn;
    x = new int [n];
    y = new int [n];
    for (int i=0;i<n;i++)
    {
      x[i]=0;
      y[i]=0;
    }
 
  }
  Points::Points(int nn,int*xx,int *yy)
  {
    n=nn;
    x= new int [n];
    y= new int [n];
    for (int i = 0; i < n; ++i)
    {
      x[i]=xx[i];
      y[i]=yy[i];
    }
  }
  void Points::set_x (int i,int value)
    this->x[i]=value;
  }
 
  void Points::set_y(int i, int value)
  {
    this->y[i]=value;
  }
  int Points::get_x(int i)
  {
    return this->x[i];
  }
 
  int Points::get_y(int i) 
  {
    return this->y[i];
  }
  int Points::get_n()
  {
    return this->n;
  }
 
 Points::~Points()
 {}

#include "myarea.h"
#include <gtkmm/main.h>
#include <gtkmm/window.h>
 
int main(int argc, char** argv)
{
   Gtk::Main kit(argc, argv);
 
   Gtk::Window win;
   win.set_title("DrawingArea");
   win.set_size_request(400, 300);
 
   MyArea area;
   win.add(area);
   area.show();
 
   Gtk::Main::run(win);
 
   return 0;
}