[Ubuntu] Cycle the mouse between displays

cycle_mouse_on_display.py

#!/usr/bin/python3

'''
[Ubuntu] Cycle the mouse between displays.

Suggestion: setup keyboard shortcuts such as: 
- "super + tab" to "cycle_mouse_on_display.py"
- "super + shift + tab" to "cycle_mouse_on_display.py --reverse"

- Tested on Ubuntu 17.04. 
- To make it work on Ubuntu 17.10, replace Wayland with Xorg:
  Edit /etc/gdm3/custom.conf and uncomment `WaylandEnable=false`.
'''

import subprocess
import sys

# TODO: Determine dynamically.
DISPLAY_CENTER = [
    [960, 838],     # screen 1
    [2460, 909],    # screen 2
    [3840, 1029]    # screen 3
]

# TODO: Determine dynamically.
DISPLAY_X_BORDERS = [
    [0, 1920],      # screen 1: landscape
    [1921, 2999],   # screen 2: portrait
    [3000, 4680]    # screen 3: landscape
]

def get_mouse_location():
    '''
    Example location: "x:1004 y:858 screen:0 window:56623111"
    '''
    cmd = 'xdotool getmouselocation'
    result = subprocess.run(cmd.split(), stdout=subprocess.PIPE).stdout.split()
    return [int(coord.decode('utf-8').split(':')[1]) for coord in result]

def get_current_display():
    '''
    In order to get the current display, we use "getmouselocation",
    which treats all displays as a single unit. Therefore, we use it
    to calculate the display based on known borders.
    '''
    current_x = get_mouse_location()[0]
    display_index = None

    for index, borders in enumerate(DISPLAY_X_BORDERS):
        border_left, border_right = borders
        if (border_left <= current_x <= border_right):
            display_index = index
            break

    return display_index

def cycle_mouse_on_display(reverse=False):
    '''
    Cycles mouse between displays.
    '''
    current_index = get_current_display()
    display_len_0 = (len(DISPLAY_CENTER) - 1)

    if reverse:
        next_index = display_len_0 if current_index == 0 else current_index - 1
    else:
        next_index = 0 if current_index == display_len_0 else current_index + 1

    next_display = DISPLAY_CENTER[next_index]
    next_x, next_y = next_display

    cmd = 'xdotool mousemove --sync {x} {y}'.format(x=next_x, y=next_y)
    subprocess.run(cmd.split())


if __name__ == '__main__':
    reverse = '--reverse' in sys.argv
    cycle_mouse_on_display(reverse)