Re: [gtkmm] Gdk::Window problem

["Andrew E. Makeev" <andrew@xxxxxxxx>]

Murray Cumming wrote:

> > Murray Cumming wrote:
> >
> >    
> >
> > > > I found the problem, why Gdk::Window in GTKMM-2.4 is not compatible now
> > > > with GdkWindow in GTK+-2.4.
> > > >
> > > >
> > > >        
> > > What do you mean? Exactly what problem are you encountering?
> > >      
>
> [snip]
>
>  
>
> > GTKMM declaring paint_layout fucntion that take
> > Glib::RefPtr<Gdk::Window> as parameter, but we cannot cast Gdk::Drawable
> > to Gdk::Window, because Gdk::Drawable is base of Gdk::Window (see
> > Glib::RefPtr casting rules).
> >    
>
> This is the only part of your email that looks like a problem that you
> have encountered. Why can't you cast Glib::RefPtr<Gdk::Drawable> to
> Glib::RefPtr<Gdk::Window> by using RefPtr::cast_dynamic, like so:
>
> Glib::RefPtr<Gdk::Drawable refDrawable;
> Glib::RefPtr<Gdk::Window> refWindow =
>  Glib::RefPtr<Gdk::Window>::cast_dynamic(refDrawable);
>
> http://www.gtkmm.org/docs/glibmm-2.4/docs/reference/html/classGlib_1_1RefPtr.html#e0
>
>  
You know, I would to apologize. I've tried that already, but had some 
compilation error, that forced me to decide that I can't cast Drawable 
to Window. Now I tried it again and everithing was working well.

> [snip]
>  
>
> > Also, If you look at GTK+ code, you will find that almost all functions
> > are taking GdkWindow (equal to GdkDrawable) as argument. And that may
> > cause potential problems for developers in GTKMM.
> >    
>
> If a GTK+ function has a GdkWindow* parameter that can actually be some
> other GdkDrawable* (not a GdkWindow*), then that would be a GTK+ bug.
> Please CC me on any such bugzilla bugs.
>
>  
There is no bugs in GTK+.
Example:

GTK+, in gtkstyle.h you see:

void gtk_paint_layout     (GtkStyle        *style,
                          GdkWindow       *window, // = GdkDrawable*, 
because of "typedef GdkDrawable GdkWindow"
                          GtkStateType     state_type,
                          gboolean         use_text,
                          GdkRectangle    *area,
                          GtkWidget       *widget,
                          const gchar     *detail,
                          gint             x,
                          gint             y,
                          PangoLayout     *layout);

GTKMM, in style.h you see:

 void paint_layout(
                 const Glib::RefPtr<Gdk::Window>&    window, // -> wrap 
of GdkWindowObject, but should be GdkDrawable (see above declaration)
                 Gtk::StateType                      state_type,
                 bool                                use_text,
                 const Gdk::Rectangle&               area,
                 Widget&                             widget,
                 const Glib::ustring&                detail,
                 int                                 x,
                 int                                 y,
                 const Glib::RefPtr<Pango::Layout>&  layout) const;

Actually, since cast_dynamic is working, that will be just some 
inconvenience when using those methods, not a bug.

Thanks for the help,
-andrew

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