Wrapper for Callbacks

[Andreas Volz <lists brachttal net>]

Hi,

for a special use I need to create a wrapper for a subset of gtk2 (gdk).
But I've some problems with the callbacks. Perhaps it's a little
off-topic, because it's written in C++. But I know no better place. Here
is my class:

class Drawbox
{
private:
  GtkWidget *window;
  void (*drawCallbackFunc);

  GtkWidget* create_drawbox_window (void);

  static gboolean
  on_drawingarea_drawbox_configure_event (GtkWidget       *widget,
                                          GdkEventConfigure *event,
                                          gpointer         user_data);

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

  static void draw_drawbox (GtkWidget *widget,
                     GdkPixmap **pixmap_p,
                     int x, int y,
                     int draw_width, int draw_height);

public:
  Drawbox ();

  void setDrawCallback (void (*drawCallbackFunc));

};

I create the windows in the constructor and create_drawbox_window() and
bind then then callbacks with gtk_signal_connect(). I could do this all
in the constructor, but it only a draft currently. But
gtk_signal_connect() seems only to like member functions if they're
defined as static. But it seems to work with static. This callback runs
then draw_drawbox().

Now I like to register my own callbacks with setDrawCallback(). This
function is then called in draw_drawbox(). But if I try this my compiler
says:

drawbox.cpp: In static member function `static void 
   Drawbox::draw_drawbox(GtkWidget*, GdkPixmap**, int, int, int, int)':
drawbox.cpp:150: error: invalid use of member
`Drawbox::drawCallbackFunc' in    static member function
make: *** [drawbox.o] Fehler 1

Any ideas? Or should I use gtkmm to avoid this problems with C++?

Gruß
Andreas