Simple & basic script to monitor device orientation & rotate sway display accordingly

monitor_accel.py

#!/usr/bin/env python

import math
import time
from subprocess import call

DEVICE_PATH = '/sys/bus/iio/devices/iio:device0'
POOL_PERIOD = 0.5
MONITOR_NAME = 'eDP-1'

ROT_NORMAL = 0
ROT_90 = 1
ROT_180 = 2
ROT_270 = 3

SQRT2 = math.sqrt(2)

def read_accel():
    with open(DEVICE_PATH + '/in_accel_scale', 'r') as f:
        s = float(f.read())
    with open(DEVICE_PATH + '/in_accel_x_raw', 'r') as f:
        x = float(f.read())
    with open(DEVICE_PATH + '/in_accel_y_raw', 'r') as f:
        y = float(f.read())
    with open(DEVICE_PATH + '/in_accel_z_raw', 'r') as f:
        z = float(f.read())
    return (s*x, s*y, s*z)


def compute_direction(x, y):
    tan_2 = y / (math.sqrt(x**2 + y**2) + x)
    if tan_2 < -1.0 - SQRT2:
        return ROT_90
    elif tan_2 < 1.0 - SQRT2:
        return ROT_NORMAL
    elif tan_2 < SQRT2 - 1.0:
        return ROT_270

    elif tan_2 < SQRT2 + 1.0:
        return ROT_180
    else:
        return ROT_90


def change_monitor(direction):
    if direction == ROT_90:
        transform = "90"
    elif direction == ROT_180:
        transform = "180"
    elif direction == ROT_270:
        transform = "270"
    else:
        transform = "normal"
    call(["swaymsg", "output", MONITOR_NAME, "transform", transform])

if __name__ == "__main__":
    previous_direction = None
    while True:
        (x,y,z) = read_accel()
        direction = compute_direction(x,y)
        if previous_direction is not None and direction != previous_direction:
            # change orientation
            change_monitor(direction)
        previous_direction = direction
        time.sleep(POOL_PERIOD)