gtk_widget_size_allocate problem

[AlannY <m alanny ru>]

Hi there, my name is Alan;

I'm writing a custom widget from GtkContainer class. It's a dummy 
widget, which simply holds any other widget ;-) Sources attached.

In my _size_allocate() function I'm allocating size for some of widget 
with gtk_widget_size_allocate function. But nothing happens. So, desired 
widget is not shown ;-)

static void
grid_size_allocate (GtkWidget     *widget,
		    GtkAllocation *allocation)
{
  Grid *grid = GRID (widget);

  if ( grid->widget && GTK_WIDGET_VISIBLE (grid->widget) )
    {
      gtk_widget_size_allocate (grid->widget, allocation);
    }
}

I'm searching in the web, but can't find any information about it. Seems 
that sizes are allocated, but widget not shown ;-) Miss I something?
#include "grid.h"

static void     grid_class_init (GridClass *class);
static void     grid_init (Grid *grid);
static void     grid_realize (GtkWidget *widget);
static void     grid_size_request (GtkWidget      *widget, GtkRequisition *requisition);
static void     grid_size_allocate (GtkWidget     *widget, GtkAllocation *allocation);

G_DEFINE_TYPE (Grid, grid, GTK_TYPE_CONTAINER)

static void
grid_class_init (GridClass *class)
{
  GtkWidgetClass *widget_class;

  widget_class = (GtkWidgetClass*) class;

  widget_class->size_request = grid_size_request;
  widget_class->size_allocate = grid_size_allocate;

  widget_class->realize = grid_realize;
}

static void
grid_init (Grid *grid)
{
  grid->widget = NULL;
}

GtkWidget*
grid_new (GtkWidget *widget)
{
  Grid *grid;

  grid = g_object_new (grid_get_type (), NULL);
  grid->widget = widget;
  gtk_widget_set_parent (grid->widget, GTK_WIDGET (grid));

  return GTK_WIDGET (grid);
}

static void
grid_realize (GtkWidget *widget)
{
  GdkWindowAttr attributes;
  gint attributes_mask;

  g_return_if_fail (widget != NULL);
  g_return_if_fail (IS_GRID (widget));

  GTK_WIDGET_SET_FLAGS (widget, GTK_REALIZED);

  attributes.x = widget->allocation.x;
  attributes.y = widget->allocation.y;
  attributes.width = widget->allocation.width;
  attributes.height = widget->allocation.height;
  attributes.wclass = GDK_INPUT_OUTPUT;
  attributes.window_type = GDK_WINDOW_CHILD;
  attributes.event_mask = gtk_widget_get_events (widget) | GDK_EXPOSURE_MASK;
  attributes.visual = gtk_widget_get_visual (widget);
  attributes.colormap = gtk_widget_get_colormap (widget);

  attributes_mask = GDK_WA_X | GDK_WA_Y | GDK_WA_VISUAL | GDK_WA_COLORMAP;
  widget->window = gdk_window_new (widget->parent->window, &attributes, attributes_mask);

  widget->style = gtk_style_attach (widget->style, widget->window);

  gdk_window_set_user_data (widget->window, widget);
}

static void
grid_size_request (GtkWidget      *widget,
		   GtkRequisition *requisition)
{
  Grid *grid = GRID (widget);

  if ( grid->widget && GTK_WIDGET_VISIBLE (grid->widget) )
    {
      GtkRequisition child_requisition;

      gtk_widget_size_request (grid->widget, &child_requisition);

      requisition->width += child_requisition.width;
      requisition->height += child_requisition.height;
    }
}

static void
grid_size_allocate (GtkWidget     *widget,
		    GtkAllocation *allocation)
{
  Grid *grid = GRID (widget);

  if ( grid->widget && GTK_WIDGET_VISIBLE (grid->widget) )
    {
      gtk_widget_size_allocate (grid->widget, allocation);
    }
}

#ifndef __GRID_H__
#define __GRID_H__

#include <gtk/gtk.h>

G_BEGIN_DECLS

#define GRID(obj)          GTK_CHECK_CAST (obj, grid_get_type (), Grid)
#define IS_GRID(obj)       GTK_CHECK_TYPE (obj, grid_get_type ())

typedef struct _Grid            Grid;
typedef struct _GridClass       GridClass;

struct _Grid
{
  GtkContainer parent;

  GtkWidget *widget;
};

struct _GridClass
{
  GtkContainerClass parent_class;
};


GtkWidget       *grid_new               (GtkWidget *widget);
GtkType         grid_get_type           (void);

G_END_DECLS

#endif

#include <stdio.h>
#include <gtk/gtk.h>

#include "grid.h"

int
main (int argc,
      char *argv[])
{
  GtkWidget *window;
  GtkWidget *grid;
  GtkWidget *button;
    
  gtk_init (&argc, &argv);

  button = gtk_button_new_with_label ("Button");

  grid = grid_new (button);
  gtk_widget_show (button);

  window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
  g_signal_connect (G_OBJECT (window), "destroy", G_CALLBACK (gtk_main_quit), NULL);

  gtk_container_add (GTK_CONTAINER (window), grid);
  gtk_widget_show (grid);

  gtk_widget_show (window);

  gtk_main ();
    
  return 0;
}