setres.py

#!/usr/bin/env python3

import subprocess


def get_monitor_name():
    monitors = subprocess.run(
        ['xrandr', '--listmonitors'],
        stdout=subprocess.PIPE,
        check=True,
    ).stdout.splitlines()[1:]
    for monitor in monitors:
        _, _, _, monitor_name = monitor.split()
        return monitor_name


def new_mode(mode_name, width, height, frame_rate):
    mode_line = subprocess.run(
        ['cvt', str(width), str(height), str(frame_rate)],
        stdout=subprocess.PIPE,
        check=True,
    ).stdout.splitlines()[1].split()[2:]
    subprocess.run(['xrandr', '--newmode', mode_name, *mode_line], check=True)
    return mode_name


def add_mode(monitor_name, mode_name):
    subprocess.run(
        ['xrandr', '--addmode', monitor_name, mode_name],
        check=True,
    )


def set_mode(monitor_name, mode_name):
    subprocess.run(
        ['xrandr', '--output', monitor_name, '--mode', mode_name],
        check=True,
    )


def main():
    monitor_name = get_monitor_name()
    width = 1920
    height = 1080
    frame_rate = 60
    mode_name = '{}x{}x{}'.format(width, height, frame_rate)
    try:
        new_mode(mode_name, 1920, 1080, 60)
        add_mode(monitor_name, mode_name)
    except subprocess.CalledProcessError:
        pass
    set_mode(monitor_name, mode_name)
    print('All Done.')


if __name__ == '__main__':
    main()