Is there a native way to achieve dynamic window color schemes in kitty?

[neelchakrabrty]

Basically, I want kitty-windows to switch to a particular color scheme when focused, and switch back to a default color scheme when not focused. Is it possible to achieve this natively in kitty?

I used the kitten @ set-colors command to try and apply a color scheme to a focused window, but it instead applies the color scheme to all windows.

[kovidgoyal]

Use the watcher facility. https://sw.kovidgoyal.net/kitty/launch/#watchers

[neelchakrabrty]

This solved my issue. This facility is insanely powerful, I love it.

[neelchakrabrty]

If anyone wants, here's my watcher.py

# ~/.config/kitty/mywatcher.py
from typing import Any, Dict

from kitty.boss import Boss
from kitty.window import Window


def on_resize(boss: Boss, window: Window, data: Dict[str, Any]) -> None:
    # Here data will contain old_geometry and new_geometry
    # Note that resize is also called the first time a window is created
    # which can be detected as old_geometry will have all zero values, in
    # particular, old_geometry.xnum and old_geometry.ynum will be zero.
    ...

def on_focus_change(boss: Boss, window: Window, data: Dict[str, Any])-> None:
    focused = data.get('focused', False)
    if focused:
        boss.call_remote_control(window, ('set-colors', f'--match=id:{window.id}', '/home/larry/.config/kitty/current-theme.conf'))
    else:
        boss.call_remote_control(window, ('set-colors', f'--match=id:{window.id}', '/home/larry/.config/kitty/kittyinactivecolor.conf'))
    ...

def on_close(boss: Boss, window: Window, data: Dict[str, Any])-> None:
    # called when window is closed, typically when the program running in
    # it exits
    ...

def on_set_user_var(boss: Boss, window: Window, data: Dict[str, Any]) -> None:
    # called when a "user variable" is set or deleted on a window. Here
    # data will contain key and value
    ...

def on_title_change(boss: Boss, window: Window, data: Dict[str, Any]) -> None:
    # called when the window title is changed on a window. Here
    # data will contain title and from_child. from_child will be True
    # when a title change was requested via escape code from the program
    # running in the terminal
    ...

def on_cmd_startstop(boss: Boss, window: Window, data: Dict[str, Any]) -> None:
    # called when the shell starts/stops executing a command. Here
    # data will contain is_start, cmdline and time.
    ...