Disable font ligatures on iTerm2 by monitoring on window size change

ligatures.py

#!/usr/bin/env python3.7
# This script monitoring iTerm2 window state,
# disable font-ligatures when window size is big enough to drag FPS down,
# and (re-)enable ligatures when window size shrinks to acceptance range.
# Put this script under AutoLaunch folder to launch automatically when iTerm2 starts,
# as described at https://iterm2.com/python-api/tutorial/running.html#auto-run-scripts

import asyncio
import iterm2


async def update(connection, window):
    if window is None:
        return

    frame = await window.async_get_frame()
    small = (frame.size.width, frame.size.height) <= (1280, 720)

    change = iterm2.LocalWriteOnlyProfile()
    change.set_ascii_ligatures(small)
    change.set_non_ascii_ligatures(small)
    for tab in window.tabs:
        await tab.current_session.async_set_profile_properties(change)


async def main(connection):
    app = await iterm2.async_get_app(connection)
    async with iterm2.VariableMonitor(connection, iterm2.VariableScopes.WINDOW,
                                      "frame", "all") as mon:
        while True:
            new_value = await mon.async_get()
            await update(connection, app.current_window)

# This instructs the script to run the "main" coroutine and to keep running even after it returns.
iterm2.run_forever(main)