Usage, manipulating mouse input

[Awarua-]

Hi,

I was wondering if someone would be able to help me with a problem I am facing.

The code below is meant to intercept the mouse input and translate it by a factor of 2.
However, it stops working after intercepting the first two on_move mouse events and locks up the mouse.
I suspect it is something to do with concurrency and the listener but am unsure.
Any help would be appreciated 😄

from pynput import mouse


class PassingMouseListenerException(Exception): pass


class Mouse:
    def __init__(self):
        self.control_display_gain = 2
        self.last_position = None
        self.mouse = mouse.Controller()

    def on_move(self, x, y):
        if self.last_position is None:
            self.last_position = (x, y)
        else:
            x_difference = (x - self.last_position[0]) * self.control_display_gain
            y_difference = (y - self.last_position[1]) * self.control_display_gain
            pos = (x_difference + self.last_position[0], y_difference + self.last_position[1])
            print("difference: {0}, {1}".format(x_difference, y_difference))
            print("old position: {0}, {1} captured position: {2}, {3} new position: {4}, {5}".format(self.last_position[0], self.last_position[1], x, y, pos[0], pos[1]))
            self.mouse.move(x_difference, y_difference)
            self.last_position = pos

    def on_click(self, x, y, button, pressed):
        print("I clicked")

    def on_scroll(self, x, y, dx, dy):
        pass

    def run(self):
        self.last_position = self.mouse.position
        with mouse.Listener(
                on_move=self.on_move,
                on_click=self.on_click,
                on_scroll=self.on_scroll) as listener:

            try:
                listener.join()
            except Exception as e:
                print("listener died: {}".format(e))

if __name__ == "__main__":
    program = Mouse()
    program.run()

[moses-palmer]

Hi,

Sorry for the late response.

I have tested your application, and it does indeed crash for me with the message short format requires (-0x7fff - 1) <= number <= 0x7fff when running under XWayland. This is caused by by the values passed to self.mouse.move: Xlib requires short integers, that is signed 16 bit values.

Now, whether this should be handled by pynput is a difficult question---one solution would be to wrap the error in a generic ValueError and mark the method as raising that particular exception, another would be to cap the input values.

The root cause, however, is in your algorithm. pynput.mouse.Listener.on_move will be called when you call self.mouse.move, thus triggering another call to move the pointer, eventually leading to an overflow. You will need to react only to user triggered move callbacks.

[moses-palmer]

As of commit e17bb06, I consider this issue to be solved. If you disagree, please re-open this issue.