I want to detect applications window name when changing focus event occurs with python xlib, so in the first step I use this code:
#!/usr/bin/env python
#-*- coding:utf-8 -*-
import Xlib.display
import time
display = Xlib.display.Display()
while True:
window = display.get_input_focus().focus
wmname = window.get_wm_name()
wmclass = window.get_wm_class()
if wmclass is None and wmname is None:
window = window.query_tree().parent
wmname = window.get_wm_name()
print "WM Name: %s" % ( wmname, )
time.sleep(3)
But I want a correct way, then I research about xlib events and find Input Focus Events and write this code:
#!/usr/bin/env python
#-*- coding:utf-8 -*-
import Xlib.display
from Xlib import X
def main():
display = Xlib.display.Display(':0')
root = display.screen().root
root.change_attributes(event_mask=Xlib.X.FocusChangeMask)
while True:
event = root.display.next_event()
#if event.type == X.FocusIn or event.type == X.FocusOut:
if event.type == X.FocusOut :
window = display.get_input_focus().focus
wmname = window.get_wm_name()
wmclass = window.get_wm_class()
if wmclass is None and wmname is None:
window = window.query_tree().parent
wmname = window.get_wm_name()
print "WM Name: %s" % ( wmname, )
if __name__ == "__main__":
main()
Sadly it's not work correctly especially in tabbed browsing on google chrome and firefox, so Is there a correct way for this situation?
Your code is almost right, but it misses two things:
WM_NAME
property, that also happen when you cycle tabs in your browser.That being said, here is a working sample:
#!/usr/bin/python3
import Xlib
import Xlib.display
disp = Xlib.display.Display()
root = disp.screen().root
NET_WM_NAME = disp.intern_atom('_NET_WM_NAME')
NET_ACTIVE_WINDOW = disp.intern_atom('_NET_ACTIVE_WINDOW')
root.change_attributes(event_mask=Xlib.X.FocusChangeMask)
while True:
try:
window_id = root.get_full_property(NET_ACTIVE_WINDOW, Xlib.X.AnyPropertyType).value[0]
window = disp.create_resource_object('window', window_id)
window.change_attributes(event_mask=Xlib.X.PropertyChangeMask)
window_name = window.get_full_property(NET_WM_NAME, 0).value
except Xlib.error.XError: #simplify dealing with BadWindow
window_name = None
print(window_name)
event = disp.next_event()
@rr- As I just corrected elsewhere, you'll want to query both the current _NET_WM_NAME
(UTF-8) and the legacy WM_NAME
(non-UTF8) properties or the default xterm configuration will return no title.
I just posted a complete working example over on your Unix & Linux StackExchange question.
To avoid sending people on a cross-reference hunt, here's a copy of the code I posted there:
#!/usr/bin/python
from contextlib import contextmanager
import Xlib
import Xlib.display
disp = Xlib.display.Display()
root = disp.screen().root
NET_ACTIVE_WINDOW = disp.intern_atom('_NET_ACTIVE_WINDOW')
NET_WM_NAME = disp.intern_atom('_NET_WM_NAME') # UTF-8
WM_NAME = disp.intern_atom('WM_NAME') # Legacy encoding
last_seen = { 'xid': None, 'title': None }
@contextmanager
def window_obj(win_id):
"""Simplify dealing with BadWindow (make it either valid or None)"""
window_obj = None
if win_id:
try:
window_obj = disp.create_resource_object('window', win_id)
except Xlib.error.XError:
pass
yield window_obj
def get_active_window():
win_id = root.get_full_property(NET_ACTIVE_WINDOW,
Xlib.X.AnyPropertyType).value[0]
focus_changed = (win_id != last_seen['xid'])
if focus_changed:
with window_obj(last_seen['xid']) as old_win:
if old_win:
old_win.change_attributes(event_mask=Xlib.X.NoEventMask)
last_seen['xid'] = win_id
with window_obj(win_id) as new_win:
if new_win:
new_win.change_attributes(event_mask=Xlib.X.PropertyChangeMask)
return win_id, focus_changed
def _get_window_name_inner(win_obj):
"""Simplify dealing with _NET_WM_NAME (UTF-8) vs. WM_NAME (legacy)"""
for atom in (NET_WM_NAME, WM_NAME):
try:
window_name = win_obj.get_full_property(atom, 0)
except UnicodeDecodeError: # Apparently a Debian distro package bug
title = "<could not decode characters>"
else:
if window_name:
win_name = window_name.value
if isinstance(win_name, bytes):
# Apparently COMPOUND_TEXT is so arcane that this is how
# tools like xprop deal with receiving it these days
win_name = win_name.decode('latin1', 'replace')
return win_name
else:
title = "<unnamed window>"
return "{} (XID: {})".format(title, win_obj.id)
def get_window_name(win_id):
if not win_id:
last_seen['title'] = "<no window id>"
return last_seen['title']
title_changed = False
with window_obj(win_id) as wobj:
if wobj:
win_title = _get_window_name_inner(wobj)
title_changed = (win_title != last_seen['title'])
last_seen['title'] = win_title
return last_seen['title'], title_changed
def handle_xevent(event):
if event.type != Xlib.X.PropertyNotify:
return
changed = False
if event.atom == NET_ACTIVE_WINDOW:
if get_active_window()[1]:
changed = changed or get_window_name(last_seen['xid'])[1]
elif event.atom in (NET_WM_NAME, WM_NAME):
changed = changed or get_window_name(last_seen['xid'])[1]
if changed:
handle_change(last_seen)
def handle_change(new_state):
"""Replace this with whatever you want to actually do"""
print(new_state)
if __name__ == '__main__':
root.change_attributes(event_mask=Xlib.X.PropertyChangeMask)
get_window_name(get_active_window()[0])
handle_change(last_seen)
while True: # next_event() sleeps until we get an event
handle_xevent(disp.next_event())
There's also a more heavily commented version in this GitHub Gist.
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