[gtkmm] Application Design Problem

[Ivan Popivanov <popivan gmx net>]

Hi,

Here is an outline of the hierarchy design that I came up with for my 
application:

Main Window: GtkWindow: main application window
 GtkVBox: to hold the menu, toolbar, application client area
    Client Area: not sure about the type of this object, see below
       GtkFixed: to manage the coordinate of few widgets that will be 
needed in the client area
          MyObjects: see below

For the client area I need something that I can draw on. My first 
thought was GtkDrawingArea, however, I run into problems when I tried to 
attach the GtkFixed child. GtkDrawingArea is not a container right? Then 
I tried GtkWindow and it didn't work either (the name is kind of 
misleading, isn't it). At the end I decided that probably the best match 
is GtkBin, the reason, the client area is going to have a single child, 
namely the GtkFixed.

My objects I created as GtkMisc (after few other tries), because I want 
them to be window less, like GtkLabel. I added function members to 
handle EXPOSE events.

THE PROBLEM is that I receive the expose event in the Client Area, so I 
can draw the background etc, however, I don't get any expose events in 
MyObjects. They are on the top of the client area, but they don't 
receive any draw messages. It seems to me that in gtkmm a signal (event) 
is propagated to only one widget.

One more thing, although I'm using gtkmm, I'm suspisous that it's a Gtk 
problem.

Any idea/explanation about event propagation in gtkmm?

TIA,

Ivan


#include <gdkmm.h>
#include <gtkmm.h>

#define APP_TITLE "Blah"

class HandView : public Gtk::Misc
{
public:
   HandView( );

protected:
   virtual bool on_expose_event( GdkEventExpose *event );
   virtual bool on_configure_event(	GdkEventConfigure *event );
};

class ViewWnd : public Gtk::Bin
{
public:
   ViewWnd( );

protected:
   virtual bool on_expose_event( GdkEventExpose *event );

private:
   Gtk::Fixed fixed_;
   HandView hand_view_;
};

class FrameWnd : public Gtk::Window
{
public:
   FrameWnd( );

private:
   Gtk::VBox wnd_vbox_;
   ViewWnd view_;
};

inline
FrameWnd::FrameWnd( )
{
   set_title( APP_TITLE );
   /*
   view_.add_events( Gdk::EXPOSURE_MASK |
                     Gdk::STRUCTURE_MASK |
                     Gdk::BUTTON_PRESS_MASK |
                     Gdk::POINTER_MOTION_MASK |
                     Gdk::BUTTON_RELEASE_MASK );
    */
   wnd_vbox_.pack_start( view_ );
   add( wnd_vbox_ );
   show_all_children( );
}

inline
ViewWnd::ViewWnd( )
{
   fixed_.put( hand_view_, 5, 5 );
   add( fixed_ );
}

bool
ViewWnd::on_configure_event(	GdkEventConfigure *event )
{
   printf( "ViewWnd: Configure: rect( x = %d, y = %d, w = %d, h = %d )\n",
           event->x, event->y,
           event->width, event->height );
   return true;
}

bool
ViewWnd::on_expose_event( GdkEventExpose *event )
{
   printf( "ViewWnd: Expose: rect( x = %d, y = %d, w = %d, h = %d )\n",
           event->area.x, event->area.y,
           event->area.width, event->area.height );

   Glib::RefPtr<Gdk::Window> win = get_window( );
   Glib::RefPtr<Gdk::GC> gc = Gdk::GC::create(win);
   Glib::RefPtr<Gdk::Colormap> colormap = get_default_colormap( );

   Gdk::Color color;
   color.set_red( 0xffff );
   color.set_green( 0 );
   color.set_blue( 0xffff );
   colormap->alloc_color( color );
   gc->set_rgb_fg_color( color );

   int x, y, w, h;
   int depth;

   win->get_geometry( x, y, w, h, depth );
   win->draw_rectangle( gc, true, 0, 0, w, h );

   return false;
}

inline
HandView::HandView( )
{
   set_size_request( 100, 100 );
}

bool
HandView::on_expose_event( GdkEventExpose *event )
{
   printf( "HandView: Expose: rect( x = %d, y = %d, w = %d, h = %d )\n",
           event->area.x, event->area.y,
           event->area.width, event->area.height );

   return false;
}

int
main( int argc, char **argv )
{
   Gtk::Main kit( argc, argv );
   FrameWnd frame_wnd;
   Gtk::Main::run( frame_wnd );
   
   return 0;
}