Filter mouse events

Question

I'm facing this issue with my mouse. In my particular case the duplicate click events are less than 100ms after the genuine event. Is it possible for me to write an event filter for my display server so that all mouse events pass through a program written by me, with the ability to drop certain events? I'm using X display server with awesome wm.

Answer 1

I'd do this on the kernel input layer. The uinput device allows you to write a userspace program that produces input layer events. If you open your mouse input device (look at /dev/input/by-id and /dev/input/by-path to identify it correctly between boots) with the grab option, then the original events will go exclusively to your program, and not to X. The X evdev driver will pick up your new device automatically.

Here is an example C program, there is also a Python library (Pypi) if you prefer Python, and probably libraries for other programming languages as well. Documentation and more sample programs are easy to google.

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Usage examples copied from python-uinput:

Generate keyboard clicks

import uinput

with uinput.Device([uinput.KEY_E, uinput.KEY_H,
                    uinput.KEY_L, uinput.KEY_O]) as device:
    device.emit_click(uinput.KEY_H)
    device.emit_click(uinput.KEY_E)
    device.emit_click(uinput.KEY_L)
    device.emit_click(uinput.KEY_L)
    device.emit_click(uinput.KEY_O)

Move mouse cursor

import uinput

with uinput.Device([uinput.REL_X, uinput.REL_Y,
                    uinput.BTN_LEFT, uinput.BTN_RIGHT]) as device:
    for i in range(20):
        device.emit(uinput.REL_X, 5)
        device.emit(uinput.REL_Y, 5)

Generate keyboard combinations

import uinput

with uinput.Device([uinput.KEY_LEFTALT, uinput.KEY_TAB]) as device:
    device.emit_combo([uinput.KEY_LEFTALT, uinput.KEY_TAB])