Question

I’m trying to implement clickable areas on the root window, using python xlib’s RECORD extension.
this is what i’ve got so far:

import sys
import os

from Xlib import X, XK, display
from Xlib.ext import record
from Xlib.protocol import rq

local_dpy = display.Display()
record_dpy = display.Display()

buttons={(0,200,0,200,"echo Hep")}
def record_callback(reply):
    if reply.category != record.FromServer:
        return
    if reply.client_swapped:
        print "* received swapped protocol data, cowardly ignored"
        return
    if not len(reply.data) or ord(reply.data[0]) < 2:
        # not an event
        return

    data = reply.data
    while len(data):
        event, data = rq.EventField(None).parse_binary_value(data, record_dpy.display, None, None)

        if event.type == X.ButtonRelease:
            print "ButtonRelease", event
            if(event.detail==1):
                for btn in buttons:
                  if(event.root_x>=btn[0] and event.root_x<=btn[1]):
                      if(event.root_y>=btn[2] and event.root_y<=btn[3]):
                          os.system(btn[4])

# Check if the extension is present
if not record_dpy.has_extension("RECORD"):
    print "RECORD extension not found"
    sys.exit(1)
r = record_dpy.record_get_version(0, 0)
print "RECORD extension version %d.%d" % (r.major_version, r.minor_version)

ctx = record_dpy.record_create_context(
        0,
        [record.CurrentClients],
        [{
                'core_requests': (0, 0),
                'core_replies': (0, 0),
                'ext_requests': (0, 0, 0, 0),
                'ext_replies': (0, 0, 0, 0),
                'delivered_events': (0, 0),
                'device_events': (X.KeyPress, X.MotionNotify),
                'errors': (0, 0),
                'client_started': False,
                'client_died': False,
        }])

record_dpy.record_enable_context(ctx, record_callback)
record_dpy.record_free_context(ctx)

the problem is: I don’t know if (and how) it’s possible to let RECORD listen for root window events only, or to filter the received events.

example: clicking the root window:

Xlib.protocol.request.QueryExtension
Xlib.protocol.request.QueryExtension
RECORD extension version 1.13
ButtonRelease Xlib.protocol.event.ButtonRelease(event_y = 0, state = 256, type = 5, child = 0, detail = 1, window = <Xlib.display.Window 0x00000000>, same_screen = 0, time = 795133824, root_y = 76, root_x = 76, root = <Xlib.display.Window 0x00000000>, event_x = 0, sequence_number = 0)
Hep

clicking firefox’s toolbar:

Xlib.protocol.request.QueryExtension
Xlib.protocol.request.QueryExtension
RECORD extension version 1.13
ButtonRelease Xlib.protocol.event.ButtonRelease(event_y = 0, state = 256, type = 5, child = 0, detail = 1, window = <Xlib.display.Window 0x00000000>, same_screen = 0, time = 795205475, root_y = 61, root_x = 92, root = <Xlib.display.Window 0x00000000>, event_x = 0, sequence_number = 0)
Hep

so i somehow have to filter the events by: checking if the event came from the root window (the events all have NULL windows, see above…), or checking if another window is above the clicked area (so I can’t have clicked the root window below).

because the event doesn’t provide window information, I think Ill do the second option, but i don’t know how to…

Answer 1

found it out myself:

def record_callback(reply):
    if reply.category != record.FromServer:
        return
    if reply.client_swapped:
        print "* received swapped protocol data, cowardly ignored"
        return
    if not len(reply.data) or ord(reply.data[0]) < 2:
        # not an event
        return

    data = reply.data
    clients=local_dpy.screen().root.query_tree().children
    while len(data):
        event, data = rq.EventField(None).parse_binary_value(data, record_dpy.display, None, None)
        if event.type == X.ButtonRelease:
            if(event.detail==1):
                for btn in buttons:
                  if(event.root_x>=btn[0] and event.root_x<=btn[1]):
                      if(event.root_y>=btn[2] and event.root_y<=btn[3]):
                          doit=1
                          for win in clients:
                              if win==local_dpy.screen().root.query_pointer().child:
                                  doit=2
                          if doit==1:
                              os.system(btn[4])

the idea is to check if the window under the pointer is one of the root window’s clients.