Question

If I want some function to be called when a window gets closed I connect with delete_event. What should I connect with if I want the function to be called when the user minimizes a Gtk Window. Something like: minimize_event? I couldn’t find anything in the docs.

Answer 1

I was at the very same crossroads, wth only some info and code on python gtk, but not in C.

After looking the docs again and again I realized I got confuse by same sounding names, unions, structures and enums and bitfields. I was handling things as booleans, when it was a bitfield thingy all along.

First:

g_signal_connect(
    G_OBJECT(window), 
    "window-state-event", 
    G_CALLBACK(callback_func), 
    userDataPointer);

Then:

gboolean callback_func(
    GtkWidget *widget,
    GdkEventWindowState *event,
    gpointer user_data)
{
    //some code
    //Minimized window check
    if(event->new_window_state & GDK_WINDOW_STATE_ICONIFIED){
    //some other code
}
//some more other code
return TRUE;
}

Remember this are bitfields and & is the “bit and” operator not the boolean &&.
GDK_WINDOW_STATE_ICONIFIED =2 or 10 in binary
and event->new_window_state is an int of which the second bit is active

A Widget can be both maximized and minimized at the same time,
GDK_WINDOW_STATE_MAXIMIZED = 4 or 100

If you minimized a maximized window itsevent->new_window_state = 6 or 110

You can experiment and see what works best for you.

More info:

• http://developer.gnome.org/gtk/stable/GtkWidget.html#GtkWidget-window-state-event
• http://developer.gnome.org/gdk/stable/gdk-Event-Structures.html#GdkEventWindowState

Final Beware and caveats:

I’m using gtk+2, because of dual win&lin development. The newer gtk+3 might do some things different.

The Gnome Developer Site site has some links broken or wrong, or partially re-writen, with some errors. The page on the first url I put above has

gboolean user_function (GtkWidget *widget,GdkEvent  *event,gpointer user_data){}

while the manual in the source code as well as other downloadable manuals has the correct:

gboolean user_function (
    GtkWidget *widget,
    GdkEventWindowState *event, 
    gpointer user_data){}

The page also has the incorrect or broken link for the gtk3 page for GdkEventWindowState.
The gtk+3 version seems as wrong as the gtk+2, I have not seen the gtk+3 manuals with the source code or separate so I don’t know if gtk+3 truly modifies the callback for the event and the gdk structures

For the moment as gtk+3 stabilizes*expect* inconsistencies. Use preferably the manuals that came with your source code or linux distro and version gtk+2.

I hope this helps.