3b1b-manim/animation/indication.py

from __future__ import absolute_import

import numpy as np

from constants import *

from animation.animation import Animation
from animation.movement import Homotopy
from animation.creation import ShowPartial
from animation.transform import Transform
from mobject.mobject import Mobject
from mobject.geometry import Circle
from mobject.geometry import Dot
from utils.config_ops import digest_config
from utils.rate_functions import squish_rate_func
from utils.rate_functions import there_and_back


class FocusOn(Transform):
    CONFIG = {
        "opacity": 0.2,
        "color": GREY,
        "run_time": 2,
        "remover": True,
    }

    def __init__(self, mobject_or_point, **kwargs):
        digest_config(self, kwargs)
        big_dot = Dot(
            radius=FRAME_X_RADIUS + FRAME_Y_RADIUS,
            stroke_width=0,
            fill_color=self.color,
            fill_opacity=0,
        )
        little_dot = Dot(radius=0)
        little_dot.set_fill(self.color, opacity=self.opacity)
        little_dot.move_to(mobject_or_point)

        Transform.__init__(self, big_dot, little_dot, **kwargs)


class Indicate(Transform):
    CONFIG = {
        "rate_func": there_and_back,
        "scale_factor": 1.2,
        "color": YELLOW,
    }

    def __init__(self, mobject, **kwargs):
        digest_config(self, kwargs)
        target = mobject.copy()
        target.scale_in_place(self.scale_factor)
        target.set_color(self.color)
        Transform.__init__(self, mobject, target, **kwargs)


class CircleIndicate(Indicate):
    CONFIG = {
        "rate_func": squish_rate_func(there_and_back, 0, 0.8),
        "remover": True
    }

    def __init__(self, mobject, **kwargs):
        digest_config(self, kwargs)
        circle = Circle(color=self.color, **kwargs)
        circle.surround(mobject)
        Indicate.__init__(self, circle, **kwargs)


class ShowPassingFlash(ShowPartial):
    CONFIG = {
        "time_width": 0.1,
        "remover": True,
    }

    def get_bounds(self, alpha):
        alpha *= (1 + self.time_width)
        alpha -= self.time_width / 2.0
        lower = max(0, alpha - self.time_width / 2.0)
        upper = min(1, alpha + self.time_width / 2.0)
        return (lower, upper)

    def clean_up(self, *args, **kwargs):
        ShowPartial.clean_up(self, *args, **kwargs)
        for submob, start_submob in self.get_all_families_zipped():
            submob.pointwise_become_partial(start_submob, 0, 1)


class ShowCreationThenDestruction(ShowPassingFlash):
    CONFIG = {
        "time_width": 2.0,
        "run_time": 1,
    }


class ApplyWave(Homotopy):
    CONFIG = {
        "direction": DOWN,
        "amplitude": 0.2,
        "run_time": 1,
        "apply_function_kwargs": {
            "maintain_smoothness": False,
        },
    }

    def __init__(self, mobject, **kwargs):
        digest_config(self, kwargs, locals())
        left_x = mobject.get_left()[0]
        right_x = mobject.get_right()[0]
        vect = self.amplitude * self.direction

        def homotopy(x, y, z, t):
            start_point = np.array([x, y, z])
            alpha = (x - left_x) / (right_x - left_x)
            power = np.exp(2 * (alpha - 0.5))
            nudge = there_and_back(t**power)
            return np.array([x, y, z]) + nudge * vect
        Homotopy.__init__(self, homotopy, mobject, **kwargs)


class WiggleOutThenIn(Animation):
    CONFIG = {
        "scale_value": 1.1,
        "rotation_angle": 0.01 * TAU,
        "n_wiggles": 6,
        "run_time": 2,
        "scale_about_point": None,
        "rotate_about_point": None,
    }

    def __init__(self, mobject, **kwargs):
        digest_config(self, kwargs)
        if self.scale_about_point is None:
            self.scale_about_point = mobject.get_center()
        if self.rotate_about_point is None:
            self.rotate_about_point = mobject.get_center()
        Animation.__init__(self, mobject, **kwargs)

    def update_submobject(self, submobject, starting_sumobject, alpha):
        submobject.points[:, :] = starting_sumobject.points
        submobject.scale(
            interpolate(1, self.scale_value, there_and_back(alpha)),
            about_point=self.scale_about_point
        )
        submobject.rotate(
            wiggle(alpha, self.n_wiggles) * self.rotation_angle,
            about_point=self.rotate_about_point
        )


class Vibrate(Animation):
    CONFIG = {
        "spatial_period": 6,
        "temporal_period": 1,
        "overtones": 4,
        "amplitude": 0.5,
        "radius": FRAME_X_RADIUS / 2,
        "run_time": 3.0,
        "rate_func": None
    }

    def __init__(self, mobject=None, **kwargs):
        if mobject is None:
            mobject = Line(3 * LEFT, 3 * RIGHT)
        Animation.__init__(self, mobject, **kwargs)

    def wave_function(self, x, t):
        return sum([
            reduce(op.mul, [
                self.amplitude / (k**2),  # Amplitude
                np.sin(2 * np.pi * (k**1.5) * t / \
                       self.temporal_period),  # Frequency
                # Number of waves
                np.sin(2 * np.pi * k * x / self.spatial_period)
            ])
            for k in range(1, self.overtones + 1)
        ])

    def update_mobject(self, alpha):
        time = alpha * self.run_time
        families = map(
            Mobject.submobject_family,
            [self.mobject, self.starting_mobject]
        )
        for mob, start in zip(*families):
            mob.points = np.apply_along_axis(
                lambda (x, y, z): (x, y + self.wave_function(x, time), z),
                1, start.points
            )


class TurnInsideOut(Transform):
    CONFIG = {
        "path_arc": TAU / 4,
    }

    def __init__(self, mobject, **kwargs):
        mobject.sort_points(np.linalg.norm)
        mob_copy = mobject.copy()
        mob_copy.sort_points(lambda p: -np.linalg.norm(p))
        Transform.__init__(self, mobject, mob_copy, **kwargs)