gdk_draw_gray_image crash

[Pradeep <pradeep ncoretech com>]

Hi ,

      I am trying to  use gdk_draw_gray_image in the following program
but the application crashes when I run  the apllication program at
gdk_draw_gray_image , can anyone tell me the problem  I am facing ,

   I am using Xfbdev for this purpose , could that be a problem related
to
Xserver ?

Waiting for your reply
Thanks ,

Pradeep

#include <gtk/gtk.h>

#define IMAGE_WIDTH      255
#define IMAGE_HEIGHT     255

 guchar rgbbuf[IMAGE_WIDTH * IMAGE_HEIGHT  ];

 gboolean on_darea_expose (GtkWidget *widget,
                           GdkEventExpose *event,
                           gpointer user_data);

 int
 main (int argc, char *argv[])
 {
   GtkWidget *window, *darea;
   gint x, y;
   guchar *pos;

   gtk_init (&argc, &argv);
   gdk_rgb_init();
   window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
   darea = gtk_drawing_area_new();
   gtk_drawing_area_size (GTK_DRAWING_AREA (darea), IMAGE_WIDTH, IMAGE_HEIGHT);
   gtk_container_add (GTK_CONTAINER (window), darea);
   gtk_signal_connect (GTK_OBJECT (darea), "expose-event",
                       GTK_SIGNAL_FUNC (on_darea_expose), NULL);
   gtk_widget_show_all (window);

   /* Set up the RGB buffer. */
   pos = rgbbuf;
/* pradeep */
   for (y = 0; y < IMAGE_HEIGHT; y++)
     {
       for (x = 0; x < IMAGE_WIDTH; x++)
         {
        //   *pos++ = x - x % 32;                   
        //   *pos++ = (x / 32) * 4 + y - y % 32;   
        //   *pos++ = y - y % 32;                  
             *pos++ = x;
         }
     }
  
  /* pradeep */
   
   gtk_main();
   return 0;
 }


 gboolean
 on_darea_expose (GtkWidget *widget,
                  GdkEventExpose *event,
                  gpointer user_data)
 {
   gdk_draw_gray_image (widget->window,widget->style->fg_gc[GTK_WIDGET_STATE (widget)],
                       0, 0, IMAGE_WIDTH, IMAGE_HEIGHT,
                       GDK_RGB_DITHER_NONE, rgbbuf, IMAGE_WIDTH );
 }