signals of destroying window

cdar · **Joined:** Thu Dec 22, 2011 5:38 pm **Posts:** 7

Hi!

I've a window which I close by pressing X, and I want to know when it will disappear from screen. Signals 'destroy' and 'delete-event' don't work that way.

Thanks.

abhijangda · **Joined:** Sun Apr 03, 2011 11:12 am **Posts:** 63

please provide more information to your problem!!!

cdar · **Joined:** Thu Dec 22, 2011 5:38 pm **Posts:** 7

Code:

#!/usr/bin/env python

from gi.repository import Gtk
import time

def callback(signal, close=False):
    print 'got signal: "%s", window is still present on the screen' % (signal,)
    time.sleep(5)
    if close: Gtk.main_quit()

w = Gtk.Window()
w.set_default_size(400, 300)
w.set_position(Gtk.WindowPosition.CENTER)

w.connect('delete-event', lambda w,e: callback('delete-event'))
w.connect('destroy', lambda w: callback('destroy', True))

w.show_all()
Gtk.main()

I want to execute code when the window is NOT present on screen.

Joel · **Posted:** Sat Dec 24, 2011 3:32 pm

Maybe "unrealize" signal will help.

cdar · **Joined:** Thu Dec 22, 2011 5:38 pm **Posts:** 7

Unfortunately not.

connect_after is not helping either.

errol · **Posted:** Sun Dec 25, 2011 8:50 am

Hi,
Screen redraws are performed during idle time in the main loop. So if you want to wait for the screen to be redraw with out the window and then execute some code you will need to add an idle call back, but at a lower priority. What will happen is the normal signals will occur when we ask for the window to be destroyed, on the "destroy" signal we add an idle call back. We then let control return back to the main loop. All other idle call backs happen that deal with redraws, then our idle call back gets run after all the others as it has a lower priority.

Below is you code rewritten to demonstrate this.

Code:

#!/usr/bin/env python

from gi.repository import Gtk
import glib
import time

def callback(signal, close=False):
    print 'got signal: "%s", window is still present on the screen' % (signal,)
    time.sleep(1)
    if close: glib.idle_add(idle_callback)
    return False

def idle_callback():
    print 'got idle signal'
    time.sleep(5)
    Gtk.main_quit()
    return False

w = Gtk.Window()
w.set_default_size(400, 300)
w.set_position(Gtk.WindowPosition.CENTER)

w.connect('delete-event', lambda w,e: callback('delete-event'))
w.connect('destroy', lambda w: callback('destroy', True))

w.show_all()
Gtk.main()

cdar · **Joined:** Thu Dec 22, 2011 5:38 pm **Posts:** 7

It works :) Thank You.

PS.

Code:

#import glib
from gi.repository import GLib

errol · **Posted:** Sun Dec 25, 2011 11:11 am

I don't normally venture into Python, I normally stick with C and C++. But the principals of GTK+ is the same.

cdar · **Joined:** Thu Dec 22, 2011 5:38 pm **Posts:** 7

Something strange is happening.
Window is gone from screen, but it will be present on screenshot.

Code:

#!/usr/bin/env python

from gi.repository import Gtk, GLib, Gdk
import time

def destroy_callback(widget):
    print 'got destroy signal'
    time.sleep(3)
    GLib.idle_add(idle_callback)

def idle_callback():
    print 'got idle signal'

    rw = Gdk.get_default_root_window()
    rw_w = rw.get_width()
    rw_h = rw.get_height()
    p = Gdk.pixbuf_get_from_window(rw, 0, 0, rw_w, rw_h)
    i = Gtk.Image.new_from_pixbuf(p)
    w = Gtk.Window()
    w.add(i)
    w.show_all()
    w.connect('destroy', lambda w: Gtk.main_quit())
    return False

w = Gtk.Window()
w.set_default_size(400, 300)
w.set_position(Gtk.WindowPosition.CENTER)

w.connect('destroy', destroy_callback)

w.show_all()
Gtk.main()

cdar · **Joined:** Thu Dec 22, 2011 5:38 pm **Posts:** 7

Could anyone help me? Why is this happening? Window is still present on screenshot, what I'm doing wrong?

Nothing is working

Code:

while (Gtk.events_pending()) {
            Gtk.main_iteration();
}
Gdk.Display.get_default().flush();
Gdk.get_default_root_window().process_updates(true);
Gdk.Window.process_all_updates();

errol · **Posted:** Sun Jan 08, 2012 9:45 am

I am really not that good at Python, but give this a go. What I think is happening is although our redraws were done when we did the screen shot and had nothing else to do, other applications were still doing their redraws and they still had the remains of our windows image. To get around this I have used a time-out of 1 second instead of waiting for our work to be done. Hopefully in this time we would have done our work to destroy the window and the other applications would have done their redraws.

I am not sure their is a way to wait for all other applications to do their redraws. If there is then I am sure it would be pretty low level possibly at the X11 level.

Code:

#!/usr/bin/env python

from gi.repository import Gtk, GLib, Gdk
import time

def destroy_callback(widget):
    print 'got destroy signal'
    GLib.timeout_add(1000, timeout_callback)

def timeout_callback():
    print 'got timout signal'

    rw = Gdk.get_default_root_window()
    rw_w = rw.get_width()
    rw_h = rw.get_height()
    p = Gdk.pixbuf_get_from_window(rw, 0, 0, rw_w, rw_h)
    image = p.scale_simple(rw_w / 2, rw_h / 2, 2)
    i = Gtk.Image.new_from_pixbuf(image)
    w = Gtk.Window()
    w.add(i)
    w.show_all()
    w.connect('destroy', lambda w: Gtk.main_quit())
    return False

w = Gtk.Window()
w.set_default_size(400, 300)
w.set_position(Gtk.WindowPosition.CENTER)

w.connect('destroy', destroy_callback)

w.show_all()
Gtk.main()

cdar · **Joined:** Thu Dec 22, 2011 5:38 pm **Posts:** 7

Yes, it is working, but in my application time is very important and I can't wait 1sec. Unfortunatelly I know X11 programming less than GTK.

errol · **Posted:** Mon Jan 09, 2012 7:26 am

I have done some experiments, would 60 ms (0.06 second) be fine for you as this works for me on my fairly old machine.

You just need to change the line

Code:

GLib.timeout_add(1000, timeout_callback)

to

Code:

GLib.timeout_add(60, timeout_callback)

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