3b1b-manim/manimlib/mobject/mobject_update_utils.py

import inspect
from manimlib.constants import DEGREES
from manimlib.constants import RIGHT
from manimlib.mobject.mobject import Mobject


def always(method, *args, **kwargs):
    assert(inspect.ismethod(method))
    mobject = method.__self__
    assert(isinstance(mobject, Mobject))
    func = method.__func__
    mobject.add_updater(lambda m: func(m, *args, **kwargs))


def always_redraw(func):
    mob = func()
    mob.add_updater(lambda m: mob.become(func()))
    return mob


def always_shift(mobject, direction=RIGHT, rate=0.1):
    mobject.add_updater(
        lambda m, dt: m.shift(dt * rate * direction)
    )


def always_rotate(mobject, rate=20 * DEGREES, **kwargs):
    mobject.add_updater(
        lambda m, dt: m.rotate(dt * rate, **kwargs)
    )