Play animations in given timeline

timeline_of_animations.py

from typing import Iterable

def play_timeline(scene, timeline):
    """
    Plays a timeline of animations on a given scene.

    Args:
        scene (Scene): The scene to play the animations on.
        timeline (dict): A dictionary where the keys are the times at which the animations should start,
            and the values are the animations to play at that time. The values can be a single animation
            or an iterable of animations.
        
    Notes:
        Each animation in the timeline can have a different duration, so several animations can be
        running in parallel. If the value for a given time is an iterable, all the animations
        in the iterable are started at once (although they can end at different times depending
        on their run_time)

        The method returns when all animations have finished playing.

    Returns:
        None
    """
    previous_t = 0
    ending_time = 0
    for t, anims in sorted(timeline.items()):
        to_wait = t - previous_t
        if to_wait > 0:
            scene.wait(to_wait)
        previous_t = t
        if not isinstance(anims, Iterable):
            anims = [anims]
        for anim in anims:
            turn_animation_into_updater(anim)
            scene.add(anim.mobject)
            ending_time = max(ending_time, t + anim.run_time)
    if ending_time > t:
        scene.wait(ending_time-t)

class Test(Scene):
    """Example showing how to use play_timeline."""
    def construct(self):

        # Create a number line which will be used as a progress bar
        n = NumberLine(include_numbers=True, x_range=[0,12]).to_edge(DOWN)
        progress_bar = Line(n.n2p(0), n.n2p(12)).set_stroke(color=YELLOW, opacity=0.5, width=20)
        self.add(n)

        # Create a timeline of animations. One of the animations is the progress bar itself
        # going from 0 to 12 in 12 seconds. It can be used as a reference to check that
        # the other animations are playing at the right time.
        timeline = {
            0: Create(progress_bar, run_time=12, rate_func=linear),
            1: Create(Square(), run_time=10),
            2: [Create(Circle(), run_time=4),
                Create(Triangle(), run_time=2)],
            9: Write(Text("It works!").next_to(progress_bar, UP, buff=1), 
                     run_time=3)
        }
        play_timeline(self, timeline)
        self.wait()

This is the output of the given example

Test.mp4