3b1b-manim/manimlib/animation/indication.py

from __future__ import annotations

import numpy as np

from manimlib.animation.animation import Animation
from manimlib.animation.composition import AnimationGroup
from manimlib.animation.composition import Succession
from manimlib.animation.creation import ShowCreation
from manimlib.animation.creation import ShowPartial
from manimlib.animation.fading import FadeOut
from manimlib.animation.fading import FadeIn
from manimlib.animation.movement import Homotopy
from manimlib.animation.transform import Transform
from manimlib.constants import FRAME_X_RADIUS, FRAME_Y_RADIUS
from manimlib.constants import ORIGIN, RIGHT, UP
from manimlib.constants import SMALL_BUFF
from manimlib.constants import DEG
from manimlib.constants import TAU
from manimlib.constants import GREY, YELLOW
from manimlib.mobject.geometry import Circle
from manimlib.mobject.geometry import Dot
from manimlib.mobject.geometry import Line
from manimlib.mobject.shape_matchers import SurroundingRectangle
from manimlib.mobject.shape_matchers import Underline
from manimlib.mobject.types.vectorized_mobject import VMobject
from manimlib.mobject.types.vectorized_mobject import VGroup
from manimlib.utils.bezier import interpolate
from manimlib.utils.rate_functions import smooth
from manimlib.utils.rate_functions import squish_rate_func
from manimlib.utils.rate_functions import there_and_back
from manimlib.utils.rate_functions import wiggle

from typing import TYPE_CHECKING

if TYPE_CHECKING:
    from typing import Callable
    from manimlib.typing import ManimColor
    from manimlib.mobject.mobject import Mobject


class FocusOn(Transform):
    def __init__(
        self,
        focus_point: np.ndarray | Mobject,
        opacity: float = 0.2,
        color: ManimColor = GREY,
        run_time: float = 2,
        remover: bool = True,
        **kwargs
    ):
        self.focus_point = focus_point
        self.opacity = opacity
        self.color = color
        # Initialize with blank mobject, while create_target
        # and create_starting_mobject handle the meat
        super().__init__(VMobject(), run_time=run_time, remover=remover, **kwargs)

    def create_target(self) -> Dot:
        little_dot = Dot(radius=0)
        little_dot.set_fill(self.color, opacity=self.opacity)
        little_dot.add_updater(lambda d: d.move_to(self.focus_point))
        return little_dot

    def create_starting_mobject(self) -> Dot:
        return Dot(
            radius=FRAME_X_RADIUS + FRAME_Y_RADIUS,
            stroke_width=0,
            fill_color=self.color,
            fill_opacity=0,
        )


class Indicate(Transform):
    def __init__(
        self,
        mobject: Mobject,
        scale_factor: float = 1.2,
        color: ManimColor = YELLOW,
        rate_func: Callable[[float], float] = there_and_back,
        **kwargs
    ):
        self.scale_factor = scale_factor
        self.color = color
        super().__init__(mobject, rate_func=rate_func, **kwargs)

    def create_target(self) -> Mobject:
        target = self.mobject.copy()
        target.scale(self.scale_factor)
        target.set_color(self.color)
        return target


class Flash(AnimationGroup):
    def __init__(
        self,
        point: np.ndarray | Mobject,
        color: ManimColor = YELLOW,
        line_length: float = 0.2,
        num_lines: int = 12,
        flash_radius: float = 0.3,
        line_stroke_width: float = 3.0,
        run_time: float = 1.0,
        **kwargs
    ):
        self.point = point
        self.color = color
        self.line_length = line_length
        self.num_lines = num_lines
        self.flash_radius = flash_radius
        self.line_stroke_width = line_stroke_width

        self.lines = self.create_lines()
        animations = self.create_line_anims()
        super().__init__(
            *animations,
            group=self.lines,
            run_time=run_time,
            **kwargs,
        )

    def create_lines(self) -> VGroup:
        lines = VGroup()
        for angle in np.arange(0, TAU, TAU / self.num_lines):
            line = Line(ORIGIN, self.line_length * RIGHT)
            line.shift((self.flash_radius - self.line_length) * RIGHT)
            line.rotate(angle, about_point=ORIGIN)
            lines.add(line)
        lines.set_stroke(
            color=self.color,
            width=self.line_stroke_width
        )
        lines.add_updater(lambda l: l.move_to(self.point))
        return lines

    def create_line_anims(self) -> list[Animation]:
        return [
            ShowCreationThenDestruction(line)
            for line in self.lines
        ]


class CircleIndicate(Transform):
    def __init__(
        self,
        mobject: Mobject,
        scale_factor: float = 1.2,
        rate_func: Callable[[float], float] = there_and_back,
        stroke_color: ManimColor = YELLOW,
        stroke_width: float = 3.0,
        remover: bool = True,
        **kwargs
    ):
        circle = Circle(stroke_color=stroke_color, stroke_width=stroke_width)
        circle.surround(mobject)
        pre_circle = circle.copy().set_stroke(width=0)
        pre_circle.scale(1 / scale_factor)
        super().__init__(
            pre_circle, circle,
            rate_func=rate_func,
            remover=remover,
            **kwargs
        )


class ShowPassingFlash(ShowPartial):
    def __init__(
        self,
        mobject: Mobject,
        time_width: float = 0.1,
        remover: bool = True,
        **kwargs
    ):
        self.time_width = time_width
        super().__init__(
            mobject,
            remover=remover,
            **kwargs
        )

    def get_bounds(self, alpha: float) -> tuple[float, float]:
        tw = self.time_width
        upper = interpolate(0, 1 + tw, alpha)
        lower = upper - tw
        upper = min(upper, 1)
        lower = max(lower, 0)
        return (lower, upper)

    def finish(self) -> None:
        super().finish()
        for submob, start in self.get_all_families_zipped():
            submob.pointwise_become_partial(start, 0, 1)


class VShowPassingFlash(Animation):
    def __init__(
        self,
        vmobject: VMobject,
        time_width: float = 0.3,
        taper_width: float = 0.05,
        remover: bool = True,
        **kwargs
    ):
        self.time_width = time_width
        self.taper_width = taper_width
        super().__init__(vmobject, remover=remover, **kwargs)
        self.mobject = vmobject

    def taper_kernel(self, x):
        if x < self.taper_width:
            return x
        elif x > 1 - self.taper_width:
            return 1.0 - x
        return 1.0

    def begin(self) -> None:
        # Compute an array of stroke widths for each submobject
        # which tapers out at either end
        self.submob_to_widths = dict()
        for sm in self.mobject.get_family():
            widths = sm.get_stroke_widths()
            self.submob_to_widths[hash(sm)] = np.array([
                width * self.taper_kernel(x)
                for width, x in zip(widths, np.linspace(0, 1, len(widths)))
            ])
        super().begin()

    def interpolate_submobject(
        self,
        submobject: VMobject,
        starting_sumobject: None,
        alpha: float
    ) -> None:
        widths = self.submob_to_widths[hash(submobject)]

        # Create a gaussian such that 3 sigmas out on either side
        # will equals time_width
        tw = self.time_width
        sigma = tw / 6
        mu = interpolate(-tw / 2, 1 + tw / 2, alpha)
        xs = np.linspace(0, 1, len(widths))
        zs = (xs - mu) / sigma
        gaussian = np.exp(-0.5 * zs * zs)
        gaussian[abs(xs - mu) > 3 * sigma] = 0

        if len(widths * gaussian) !=0:
            submobject.set_stroke(width=widths * gaussian)


    def finish(self) -> None:
        super().finish()
        for submob, start in self.get_all_families_zipped():
            submob.match_style(start)


class FlashAround(VShowPassingFlash):
    def __init__(
        self,
        mobject: Mobject,
        time_width: float = 1.0,
        taper_width: float = 0.0,
        stroke_width: float = 4.0,
        color: ManimColor = YELLOW,
        buff: float = SMALL_BUFF,
        n_inserted_curves: int = 100,
        **kwargs
    ):
        path = self.get_path(mobject, buff)
        if mobject.is_fixed_in_frame():
            path.fix_in_frame()
        path.insert_n_curves(n_inserted_curves)
        path.set_points(path.get_points_without_null_curves())
        path.set_stroke(color, stroke_width)
        super().__init__(path, time_width=time_width, taper_width=taper_width, **kwargs)

    def get_path(self, mobject: Mobject, buff: float) -> SurroundingRectangle:
        return SurroundingRectangle(mobject, buff=buff)


class FlashUnder(FlashAround):
    def get_path(self, mobject: Mobject, buff: float) -> Underline:
        return Underline(mobject, buff=buff, stretch_factor=1.0)


class ShowCreationThenDestruction(ShowPassingFlash):
    def __init__(self, vmobject: VMobject, time_width: float = 2.0, **kwargs):
        super().__init__(vmobject, time_width=time_width, **kwargs)


class ShowCreationThenFadeOut(Succession):
    def __init__(self, mobject: Mobject, remover: bool = True, **kwargs):
        super().__init__(
            ShowCreation(mobject),
            FadeOut(mobject),
            remover=remover,
            **kwargs
        )


class AnimationOnSurroundingRectangle(AnimationGroup):
    RectAnimationType: type = Animation

    def __init__(
        self,
        mobject: Mobject,
        stroke_width: float = 2.0,
        stroke_color: ManimColor = YELLOW,
        buff: float = SMALL_BUFF,
        **kwargs
    ):
        rect = SurroundingRectangle(
            mobject,
            stroke_width=stroke_width,
            stroke_color=stroke_color,
            buff=buff,
        )
        rect.add_updater(lambda r: r.move_to(mobject))
        super().__init__(self.RectAnimationType(rect, **kwargs))


class ShowPassingFlashAround(AnimationOnSurroundingRectangle):
    RectAnimationType = ShowPassingFlash


class ShowCreationThenDestructionAround(AnimationOnSurroundingRectangle):
    RectAnimationType = ShowCreationThenDestruction


class ShowCreationThenFadeAround(AnimationOnSurroundingRectangle):
    RectAnimationType = ShowCreationThenFadeOut


class ApplyWave(Homotopy):
    def __init__(
        self,
        mobject: Mobject,
        direction: np.ndarray = UP,
        amplitude: float = 0.2,
        run_time: float = 1.0,
        **kwargs
    ):

        left_x = mobject.get_left()[0]
        right_x = mobject.get_right()[0]
        vect = amplitude * direction

        def homotopy(x, y, z, t):
            alpha = (x - left_x) / (right_x - left_x)
            power = np.exp(2.0 * (alpha - 0.5))
            nudge = there_and_back(t**power)
            return np.array([x, y, z]) + nudge * vect

        super().__init__(homotopy, mobject, **kwargs)


class WiggleOutThenIn(Animation):
    def __init__(
        self,
        mobject: Mobject,
        scale_value: float = 1.1,
        rotation_angle: float = 0.01 * TAU,
        n_wiggles: int = 6,
        scale_about_point: np.ndarray | None = None,
        rotate_about_point: np.ndarray | None = None,
        run_time: float = 2,
        **kwargs
    ):
        self.scale_value = scale_value
        self.rotation_angle = rotation_angle
        self.n_wiggles = n_wiggles
        self.scale_about_point = scale_about_point
        self.rotate_about_point = rotate_about_point
        super().__init__(mobject, run_time=run_time, **kwargs)

    def get_scale_about_point(self) -> np.ndarray:
        return self.scale_about_point or self.mobject.get_center()

    def get_rotate_about_point(self) -> np.ndarray:
        return self.rotate_about_point or self.mobject.get_center()

    def interpolate_submobject(
        self,
        submobject: Mobject,
        starting_sumobject: Mobject,
        alpha: float
    ) -> None:
        submobject.match_points(starting_sumobject)
        submobject.scale(
            interpolate(1, self.scale_value, there_and_back(alpha)),
            about_point=self.get_scale_about_point()
        )
        submobject.rotate(
            wiggle(alpha, self.n_wiggles) * self.rotation_angle,
            about_point=self.get_rotate_about_point()
        )


class TurnInsideOut(Transform):
    def __init__(self, mobject: Mobject, path_arc: float = 90 * DEG, **kwargs):
        super().__init__(mobject, path_arc=path_arc, **kwargs)

    def create_target(self) -> Mobject:
        result = self.mobject.copy().reverse_points()
        if isinstance(result, VMobject):
            result.refresh_triangulation()
        return result


class FlashyFadeIn(AnimationGroup):
    def __init__(self,
        vmobject: VMobject,
        stroke_width: float = 2.0,
        fade_lag: float = 0.0,
        time_width: float = 1.0,
        **kwargs
    ):
        outline = vmobject.copy()
        outline.set_fill(opacity=0)
        outline.set_stroke(width=stroke_width, opacity=1)

        rate_func = kwargs.get("rate_func", smooth)
        super().__init__(
            FadeIn(vmobject, rate_func=squish_rate_func(rate_func, fade_lag, 1)),
            VShowPassingFlash(outline, time_width=time_width),
            **kwargs
        )