scene.py

"""Basic canvas for animations."""


__all__ = ["Scene"]


import inspect
import random
import warnings
import platform
import copy

from tqdm import tqdm as ProgressDisplay
import numpy as np

from .. import config, logger
from ..animation.animation import Animation, Wait
from ..animation.transform import MoveToTarget, ApplyMethod
from ..camera.camera import Camera
from ..constants import *
from ..container import Container
from ..mobject.mobject import Mobject
from ..scene.scene_file_writer import SceneFileWriter
from ..utils.iterables import list_update, list_difference_update
from ..utils.hashing import get_hash_from_play_call, get_hash_from_wait_call
from ..utils.family import extract_mobject_family_members
from ..renderer.cairo_renderer import CairoRenderer
from ..utils.exceptions import EndSceneEarlyException


class Scene(Container):
    """A Scene is the canvas of your animation.

    All of your own named Scenes will be subclasses of Scene, or other named
    scenes.

    Examples
    --------
    Override the construct() method to tell Manim what should go on in the
    Scene.

    .. code-block:: python

        class MyScene(Scene):
            def construct(self):
                self.play(
                    Write(Text("Hello World!"))
                )

    Some important variables to note are:
        camera: The camera object to be used for the scene.
        file_writer : The object that writes the animations in the scene to a video file.
        mobjects : The list of mobjects present in the scene.
        foreground_mobjects : List of mobjects explicitly in the foreground.
        random_seed: The seed with which all random operations are done.

    """

    CONFIG = {
        "camera_class": Camera,
        "always_update_mobjects": False,
        "random_seed": 0,
    }

    def __init__(self, renderer=None, **kwargs):
        Container.__init__(self, **kwargs)
        if renderer is None:
            self.renderer = CairoRenderer(
                camera_class=self.camera_class,
                skip_animations=kwargs.get("skip_animations", False),
            )
        else:
            self.renderer = renderer
        self.renderer.init(self)

        self.mobjects = []
        # TODO, remove need for foreground mobjects
        self.foreground_mobjects = []
        if self.random_seed is not None:
            random.seed(self.random_seed)
            np.random.seed(self.random_seed)

    @property
    def camera(self):
        return self.renderer.camera

    def render(self):
        """
        Render this Scene.
        """
        self.setup()
        try:
            self.construct()
        except EndSceneEarlyException:
            pass
        self.tear_down()
        self.renderer.finish(self)
        logger.info(
            f"Rendered {str(self)}\nPlayed {self.renderer.num_plays} animations"
        )

    def setup(self):
        """
        This is meant to be implemented by any scenes which
        are comonly subclassed, and have some common setup
        involved before the construct method is called.
        """
        pass

    def tear_down(self):
        """
        This is meant to be implemented by any scenes which
        are comonly subclassed, and have some common method
        to be invoked before the scene ends.
        """
        pass

    def construct(self):
        """
        The primary method for constructing (i.e adding content to)
        the Scene.
        """
        pass  # To be implemented in subclasses

    def __str__(self):
        return self.__class__.__name__

    def get_attrs(self, *keys):
        """
        Gets attributes of a scene given the attribute's identifier/name.

        Parameters
        ----------
        *keys : str
            Name(s) of the argument(s) to return the attribute of.

        Returns
        -------
        list
            List of attributes of the passed identifiers.
        """
        return [getattr(self, key) for key in keys]

    def update_mobjects(self, dt, mobjects=None):
        """Update all mobjects in the Scene.

        Parameters
        ----------
        dt: int or float
            Change in time between updates. Defaults (mostly) to 1/frames_per_second
        """
        if mobjects is None:
            mobjects = self.mobjects
        for mobject in mobjects:
            mobject.update(dt)

    def should_update_mobjects(self):
        """
        Returns True if any mobject in Scene is being updated
        or if the scene has always_update_mobjects set to true.

        Returns
        -------
            bool
        """
        return self.always_update_mobjects or any(
            [mob.has_time_based_updater() for mob in self.get_mobject_family_members()]
        )

    def get_top_level_mobjects(self):
        """
        Returns all mobjects which are not submobjects.

        Returns
        -------
        list
            List of top level mobjects.
        """
        # Return only those which are not in the family
        # of another mobject from the scene
        mobjects = self.get_mobjects()
        families = [m.get_family() for m in mobjects]

        def is_top_level(mobject):
            num_families = sum([(mobject in family) for family in families])
            return num_families == 1

        return list(filter(is_top_level, mobjects))

    def get_mobject_family_members(self):
        """
        Returns list of family-members of all mobjects in scene.
        If a Circle() and a VGroup(Rectangle(),Triangle()) were added,
        it returns not only the Circle(), Rectangle() and Triangle(), but
        also the VGroup() object.

        Returns
        -------
        list
            List of mobject family members.
        """
        return extract_mobject_family_members(
            self.mobjects, use_z_index=self.renderer.camera.use_z_index
        )

    def add(self, *mobjects):
        """
        Mobjects will be displayed, from background to
        foreground in the order with which they are added.

        Parameters
        ---------
        *mobjects : Mobject
            Mobjects to add.

        Returns
        -------
        Scene
            The same scene after adding the Mobjects in.

        """
        mobjects = [*mobjects, *self.foreground_mobjects]
        self.restructure_mobjects(to_remove=mobjects)
        self.mobjects += mobjects
        return self

    def add_mobjects_among(self, values):
        """
        This is meant mostly for quick prototyping,
        e.g. to add all mobjects defined up to a point,
        call self.add_mobjects_among(locals().values())
        """
        self.add(*filter(lambda m: isinstance(m, Mobject), values))
        return self

    def add_mobjects_from_animations(self, animations):

        curr_mobjects = self.get_mobject_family_members()
        for animation in animations:
            # Anything animated that's not already in the
            # scene gets added to the scene
            mob = animation.mobject
            if mob is not None and mob not in curr_mobjects:
                self.add(mob)
                curr_mobjects += mob.get_family()

    def remove(self, *mobjects):
        """
        Removes mobjects in the passed list of mobjects
        from the scene and the foreground, by removing them
        from "mobjects" and "foreground_mobjects"

        Parameters
        ----------
        *mobjects : Mobject
            The mobjects to remove.
        """
        for list_name in "mobjects", "foreground_mobjects":
            self.restructure_mobjects(mobjects, list_name, False)
        return self

    def restructure_mobjects(
        self, to_remove, mobject_list_name="mobjects", extract_families=True
    ):
        """
        tl:wr
            If your scene has a Group(), and you removed a mobject from the Group,
            this dissolves the group and puts the rest of the mobjects directly
            in self.mobjects or self.foreground_mobjects.

        In cases where the scene contains a group, e.g. Group(m1, m2, m3), but one
        of its submobjects is removed, e.g. scene.remove(m1), the list of mobjects
        will be edited to contain other submobjects, but not m1, e.g. it will now
        insert m2 and m3 to where the group once was.

        Parameters
        ----------
        to_remove : Mobject
            The Mobject to remove.

        mobject_list_name : str, optional
            The list of mobjects ("mobjects", "foreground_mobjects" etc) to remove from.

        extract_families : bool, optional
            Whether the mobject's families should be recursively extracted.

        Returns
        -------
        Scene
            The Scene mobject with restructured Mobjects.
        """
        if extract_families:
            to_remove = extract_mobject_family_members(
                to_remove, use_z_index=self.renderer.camera.use_z_index
            )
        _list = getattr(self, mobject_list_name)
        new_list = self.get_restructured_mobject_list(_list, to_remove)
        setattr(self, mobject_list_name, new_list)
        return self

    def get_restructured_mobject_list(self, mobjects, to_remove):
        """
        Given a list of mobjects and a list of mobjects to be removed, this
        filters out the removable mobjects from the list of mobjects.

        Parameters
        ----------

        mobjects : list
            The Mobjects to check.

        to_remove : list
            The list of mobjects to remove.

        Returns
        -------
        list
            The list of mobjects with the mobjects to remove removed.
        """

        new_mobjects = []

        def add_safe_mobjects_from_list(list_to_examine, set_to_remove):
            for mob in list_to_examine:
                if mob in set_to_remove:
                    continue
                intersect = set_to_remove.intersection(mob.get_family())
                if intersect:
                    add_safe_mobjects_from_list(mob.submobjects, intersect)
                else:
                    new_mobjects.append(mob)

        add_safe_mobjects_from_list(mobjects, set(to_remove))
        return new_mobjects

    # TODO, remove this, and calls to this
    def add_foreground_mobjects(self, *mobjects):
        """
        Adds mobjects to the foreground, and internally to the list
        foreground_mobjects, and mobjects.

        Parameters
        ----------
        *mobjects : Mobject
            The Mobjects to add to the foreground.

        Returns
        ------
        Scene
            The Scene, with the foreground mobjects added.
        """
        self.foreground_mobjects = list_update(self.foreground_mobjects, mobjects)
        self.add(*mobjects)
        return self

    def add_foreground_mobject(self, mobject):
        """
        Adds a single mobject to the foreground, and internally to the list
        foreground_mobjects, and mobjects.

        Parameters
        ----------
        mobject : Mobject
            The Mobject to add to the foreground.

        Returns
        ------
        Scene
            The Scene, with the foreground mobject added.
        """
        return self.add_foreground_mobjects(mobject)

    def remove_foreground_mobjects(self, *to_remove):
        """
        Removes mobjects from the foreground, and internally from the list
        foreground_mobjects.

        Parameters
        ----------
        *to_remove : Mobject
            The mobject(s) to remove from the foreground.

        Returns
        ------
        Scene
            The Scene, with the foreground mobjects removed.
        """
        self.restructure_mobjects(to_remove, "foreground_mobjects")
        return self

    def remove_foreground_mobject(self, mobject):
        """
        Removes a single mobject from the foreground, and internally from the list
        foreground_mobjects.

        Parameters
        ----------
        mobject : Mobject
            The mobject to remove from the foreground.

        Returns
        ------
        Scene
            The Scene, with the foreground mobject removed.
        """
        return self.remove_foreground_mobjects(mobject)

    def bring_to_front(self, *mobjects):
        """
        Adds the passed mobjects to the scene again,
        pushing them to he front of the scene.

        Parameters
        ----------
        *mobjects : Mobject
            The mobject(s) to bring to the front of the scene.

        Returns
        ------
        Scene
            The Scene, with the mobjects brought to the front
            of the scene.
        """
        self.add(*mobjects)
        return self

    def bring_to_back(self, *mobjects):
        """
        Removes the mobject from the scene and
        adds them to the back of the scene.

        Parameters
        ----------
        *mobjects : Mobject
            The mobject(s) to push to the back of the scene.

        Returns
        ------
        Scene
            The Scene, with the mobjects pushed to the back
            of the scene.
        """
        self.remove(*mobjects)
        self.mobjects = list(mobjects) + self.mobjects
        return self

    def clear(self):
        """
        Removes all mobjects present in self.mobjects
        and self.foreground_mobjects from the scene.

        Returns
        ------
        Scene
            The Scene, with all of its mobjects in
            self.mobjects and self.foreground_mobjects
            removed.
        """
        self.mobjects = []
        self.foreground_mobjects = []
        return self

    def get_mobjects(self):
        """
        Returns all the mobjects in self.mobjects

        Returns
        ------
        list
            The list of self.mobjects .
        """
        return list(self.mobjects)

    def get_mobject_copies(self):
        """
        Returns a copy of all mobjects present in
        self.mobjects .

        Returns
        ------
        list
            A list of the copies of all the mobjects
            in self.mobjects
        """
        return [m.copy() for m in self.mobjects]

    def get_moving_mobjects(self, *animations):
        """
        Gets all moving mobjects in the passed animation(s).

        Parameters
        ----------
        *animations : Animation
            The animations to check for moving mobjects.

        Returns
        ------
        list
            The list of mobjects that could be moving in
            the Animation(s)
        """
        # Go through mobjects from start to end, and
        # as soon as there's one that needs updating of
        # some kind per frame, return the list from that
        # point forward.
        animation_mobjects = [anim.mobject for anim in animations]
        mobjects = self.get_mobject_family_members()
        for i, mob in enumerate(mobjects):
            update_possibilities = [
                mob in animation_mobjects,
                len(mob.get_family_updaters()) > 0,
                mob in self.foreground_mobjects,
            ]
            if any(update_possibilities):
                return mobjects[i:]
        return []

    def get_moving_and_stationary_mobjects(self, animations):
        moving_mobjects = self.get_moving_mobjects(*animations)
        all_mobjects = list_update(self.mobjects, self.foreground_mobjects)
        all_mobject_families = extract_mobject_family_members(
            all_mobjects,
            use_z_index=self.renderer.camera.use_z_index,
            only_those_with_points=True,
        )
        moving_mobjects = self.get_moving_mobjects(*animations)
        all_moving_mobject_families = extract_mobject_family_members(
            moving_mobjects,
            use_z_index=self.renderer.camera.use_z_index,
        )
        stationary_mobjects = list_difference_update(
            all_mobject_families, all_moving_mobject_families
        )
        return all_moving_mobject_families, stationary_mobjects

    def compile_play_args_to_animation_list(self, *args, **kwargs):
        """
        Each arg can either be an animation, or a mobject method
        followed by that methods arguments (and potentially follow
        by a dict of kwargs for that method).
        This animation list is built by going through the args list,
        and each animation is simply added, but when a mobject method
        is hit, a MoveToTarget animation is built using the args that
        follow up until either another animation is hit, another method
        is hit, or the args list runs out.

        Parameters
        ----------
        *args : Animation or method of a mobject, which is followed by that method's arguments

        **kwargs : any named arguments like run_time or lag_ratio.

        Returns
        -------
        list : list of animations with the parameters applied to them.
        """
        animations = []
        state = {
            "curr_method": None,
            "last_method": None,
            "method_args": [],
        }

        def compile_method(state):
            if state["curr_method"] is None:
                return
            mobject = state["curr_method"].__self__
            if state["last_method"] and state["last_method"].__self__ is mobject:
                animations.pop()
                # method should already have target then.
            else:
                mobject.generate_target()
            #
            if len(state["method_args"]) > 0 and isinstance(
                state["method_args"][-1], dict
            ):
                method_kwargs = state["method_args"].pop()
            else:
                method_kwargs = {}
            state["curr_method"].__func__(
                mobject.target, *state["method_args"], **method_kwargs
            )
            animations.append(MoveToTarget(mobject))
            state["last_method"] = state["curr_method"]
            state["curr_method"] = None
            state["method_args"] = []

        for arg in args:
            if isinstance(arg, Animation):
                compile_method(state)
                animations.append(arg)
            elif inspect.ismethod(arg):
                compile_method(state)
                state["curr_method"] = arg
            elif state["curr_method"] is not None:
                state["method_args"].append(arg)
            elif isinstance(arg, Mobject):
                raise ValueError(
                    """
                    I think you may have invoked a method
                    you meant to pass in as a Scene.play argument
                    """
                )
            else:
                raise ValueError("Invalid play arguments")
        compile_method(state)

        for animation in animations:
            # This is where kwargs to play like run_time and rate_func
            # get applied to all animations
            animation.update_config(**kwargs)

        return animations

    def get_time_progression(
        self, run_time, n_iterations=None, override_skip_animations=False
    ):
        """
        You will hardly use this when making your own animations.
        This method is for Manim's internal use.

        Returns a CommandLine ProgressBar whose ``fill_time``
        is dependent on the ``run_time`` of an animation,
        the iterations to perform in that animation
        and a bool saying whether or not to consider
        the skipped animations.

        Parameters
        ----------
        run_time : float
            The ``run_time`` of the animation.

        n_iterations : int, optional
            The number of iterations in the animation.

        override_skip_animations : bool, optional
            Whether or not to show skipped animations in the progress bar.

        Returns
        -------
        ProgressDisplay
            The CommandLine Progress Bar.
        """
        if self.renderer.skip_animations and not override_skip_animations:
            times = [run_time]
        else:
            step = 1 / self.renderer.camera.frame_rate
            times = np.arange(0, run_time, step)
        time_progression = ProgressDisplay(
            times,
            total=n_iterations,
            leave=config["leave_progress_bars"],
            ascii=True if platform.system() == "Windows" else None,
            disable=not config["progress_bar"],
        )
        return time_progression

    def get_animation_time_progression(self, animations):
        """
        You will hardly use this when making your own animations.
        This method is for Manim's internal use.

        Uses :func:`~.get_time_progression` to obtain a
        CommandLine ProgressBar whose ``fill_time`` is
        dependent on the qualities of the passed Animation,

        Parameters
        ----------
        animations : List[:class:`~.Animation`, ...]
            The list of animations to get
            the time progression for.

        Returns
        -------
        ProgressDisplay
            The CommandLine Progress Bar.
        """
        run_time = self.get_run_time(animations)
        time_progression = self.get_time_progression(run_time)
        time_progression.set_description(
            "".join(
                [
                    "Animation {}: ".format(self.renderer.num_plays),
                    str(animations[0]),
                    (", etc." if len(animations) > 1 else ""),
                ]
            )
        )
        return time_progression

    def get_wait_time_progression(self, duration, stop_condition):
        """
        This method is used internally to obtain the CommandLine
        Progressbar for when self.wait() is called in a scene.

        Parameters
        ----------
        duration : int or float
            duration of wait time

        stop_condition : function
            The function which determines whether to continue waiting.

        Returns
        -------
        ProgressBar
            The CommandLine ProgressBar of the wait time

        """
        if stop_condition is not None:
            time_progression = self.get_time_progression(
                duration,
                n_iterations=-1,  # So it doesn't show % progress
                override_skip_animations=True,
            )
            time_progression.set_description(
                "Waiting for {}".format(stop_condition.__name__)
            )
        else:
            time_progression = self.get_time_progression(duration)
            time_progression.set_description(
                "Waiting {}".format(self.renderer.num_plays)
            )
        return time_progression

    def get_run_time(self, animations):
        """
        Gets the total run time for a list of animations.

        Parameters
        ----------
        animations : List[:class:`Animation`, ...]
            A list of the animations whose total
            ``run_time`` is to be calculated.

        Returns
        -------
        float
            The total ``run_time`` of all of the animations in the list.
        """

        return np.max([animation.run_time for animation in animations])

    def play(self, *args, **kwargs):
        self.renderer.play(self, *args, **kwargs)

    def wait(self, duration=DEFAULT_WAIT_TIME, stop_condition=None):
        self.play(Wait(duration=duration, stop_condition=stop_condition))

    def wait_until(self, stop_condition, max_time=60):
        """
        Like a wrapper for wait().
        You pass a function that determines whether to continue waiting,
        and a max wait time if that is never fulfilled.

        Parameters
        ----------
        stop_condition : function
            The function whose boolean return value determines whether to continue waiting

        max_time : int or float, optional
            The maximum wait time in seconds, if the stop_condition is never fulfilled.
        """
        self.wait(max_time, stop_condition=stop_condition)

    def play_internal(self, *args, **kwargs):
        """
        This method is used to prep the animations for rendering,
        apply the arguments and parameters required to them,
        render them, and write them to the video file.

        Parameters
        ----------
        *args : Animation or mobject with mobject method and params
        **kwargs : named parameters affecting what was passed in *args e.g
            run_time, lag_ratio etc.
        """
        if len(args) == 0:
            warnings.warn("Called Scene.play with no animations")
            return

        animations = self.compile_play_args_to_animation_list(*args, **kwargs)
        if (
            len(animations) == 1
            and isinstance(animations[0], Wait)
            and not self.should_update_mobjects()
        ):
            self.add_static_frames(animations[0].duration)
            return

        for animation in animations:
            animation.begin()

        moving_mobjects = None
        static_mobjects = None
        duration = None
        stop_condition = None
        time_progression = None
        if len(animations) == 1 and isinstance(animations[0], Wait):
            # TODO, be smart about setting a static image
            # the same way Scene.play does
            duration = animations[0].duration
            stop_condition = animations[0].stop_condition
            self.static_image = None
            time_progression = self.get_wait_time_progression(duration, stop_condition)
        else:
            # Paint all non-moving objects onto the screen, so they don't
            # have to be rendered every frame
            (
                moving_mobjects,
                stationary_mobjects,
            ) = self.get_moving_and_stationary_mobjects(animations)
            self.renderer.update_frame(
                self, self.renderer.camera.frame_rate, mobjects=stationary_mobjects
            )
            self.static_image = self.renderer.get_frame()
            time_progression = self.get_animation_time_progression(animations)

        last_t = 0
        for t in time_progression:
            dt = t - last_t
            last_t = t
            for animation in animations:
                animation.update_mobjects(dt)
                alpha = t / animation.run_time
                animation.interpolate(alpha)

            self.renderer.update_frame(self, dt, moving_mobjects, self.static_image)
            self.renderer.add_frame(self.renderer.get_frame())
            if stop_condition is not None and stop_condition():
                time_progression.close()
                break

        for animation in animations:
            animation.finish()
            animation.clean_up_from_scene(self)

    def add_static_frames(self, duration):
        self.renderer.update_frame(self, self.renderer.camera.frame_rate)
        dt = 1 / self.renderer.camera.frame_rate
        self.renderer.add_frame(
            self.renderer.get_frame(),
            num_frames=int(duration / dt),
        )

    def add_sound(self, sound_file, time_offset=0, gain=None, **kwargs):
        """
        This method is used to add a sound to the animation.

        Parameters
        ----------
        sound_file : str
            The path to the sound file.

        time_offset : int,float, optional
            The offset in the sound file after which
            the sound can be played.

        gain :

        """
        if self.renderer.skip_animations:
            return
        time = self.time + time_offset
        self.renderer.file_writer.add_sound(sound_file, time, gain, **kwargs)