Linux still prints screen when hitting "print"

[MrEliptik]

Hi, I'm trying to use pyxhook to catch users hitting the "print screen" key. I successfully catch the event, but linux still run the default behavior, which is making a screenshot. With pyhook on Windows, the behavior is different, as the default "print screen" action is not happening.

One solution could be to remove the mapping between "print screen" and screenshot under linux, but I'd like to avoid that, making life easier to support different distros and OS.

Is there a way to "consume" the event after it was caught by my script ?

[MrEliptik]

I've tested again on windows with Pyhook and the normal behavior still happens... It's just that I couldn't see it. Do you have an idea of how to consume the event so that it's not grabbed by other apps?

[calumah]

I don't think that's possible with pyxhook right now. You can see #15 it's the same problem. Otherwise you can change the configuration of keyboard shortcuts with python on linux but this depends on the desktop environment and is not recommended. Users are free to change their keyboard shortcuts as they wish, or else you must use a dead key for both systems.

[MrEliptik]

@calumah Indeed it seems impossible with pyxhook right now. I've been digging a bit more into xlib and there might be something with XGrabKey(<Display*>, AnyKey, AnyModifier, <window>, false, GrabModeAsync, GrabModeAsync); see this link. I'll try to investigate tonight and post updates for futur reference.

[MrEliptik]

I've finally managed to do what I want! For anyone curious, here's how to completely grab the 'print' key, without event propagation:

from Xlib.display import Display
from Xlib import X, XK

def handle_event(aEvent):
    if aEvent.type == X.KeyPress:
        print(aEvent)

# current display
root = Display().screen().root

# To check the keycode of your key
'''
keysym = XK.string_to_keysym('Print')
print(disp.keysym_to_keycode(keysym))
''''
# 107 is the keycode for 'print'
root.grab_key(107, X.Mod2Mask, 0, X.GrabModeAsync, X.GrabModeAsync)

# listen for events
while 1:
        event = root.display.next_event()
        handle_event(event)

This will print the event details. Here is an output example:

<class 'Xlib.protocol.event.KeyPress'>(type = 2, detail = 107, sequence_number = 13, time = 11384954, root = <<class 'Xlib.display.Window'> 0x000001fe>, window = <<class 'Xlib.display.Window'> 0x000001fe>, child = <<class 'Xlib.display.Window'> 0x004001a4>, root_x = 2182, root_y = 2612, event_x = 2182, event_y = 2612, state = 16, same_screen = 1)