"""Animations that introduce mobjects to scene by growing them from points.
.. manim:: Growing
class Growing(Scene):
def construct(self):
square = Square()
circle = Circle()
triangle = Triangle()
arrow = Arrow(LEFT, RIGHT)
star = Star()
VGroup(square, circle, triangle).set_x(0).arrange(buff=1.5).set_y(2)
VGroup(arrow, star).move_to(DOWN).set_x(0).arrange(buff=1.5).set_y(-2)
self.play(GrowFromPoint(square, ORIGIN))
self.play(GrowFromCenter(circle))
self.play(GrowFromEdge(triangle, DOWN))
self.play(GrowArrow(arrow))
self.play(SpinInFromNothing(star))
"""
from __future__ import annotations
__all__ = [
"GrowFromPoint",
"GrowFromCenter",
"GrowFromEdge",
"GrowArrow",
"SpinInFromNothing",
]
import typing
import numpy as np
from ..animation.transform import Transform
from ..constants import PI
from ..utils.paths import spiral_path
if typing.TYPE_CHECKING:
from manim.mobject.geometry.line import Arrow
from ..mobject.mobject import Mobject
[docs]class GrowFromPoint(Transform):
"""Introduce an :class:`~.Mobject` by growing it from a point.
Parameters
----------
mobject
The mobjects to be introduced.
point
The point from which the mobject grows.
point_color
Initial color of the mobject before growing to its full size. Leave empty to match mobject's color.
Examples
--------
.. manim :: GrowFromPointExample
class GrowFromPointExample(Scene):
def construct(self):
dot = Dot(3 * UR, color=GREEN)
squares = [Square() for _ in range(4)]
VGroup(*squares).set_x(0).arrange(buff=1)
self.add(dot)
self.play(GrowFromPoint(squares[0], ORIGIN))
self.play(GrowFromPoint(squares[1], [-2, 2, 0]))
self.play(GrowFromPoint(squares[2], [3, -2, 0], RED))
self.play(GrowFromPoint(squares[3], dot, dot.get_color()))
"""
def __init__(
self, mobject: Mobject, point: np.ndarray, point_color: str = None, **kwargs
) -> None:
self.point = point
self.point_color = point_color
super().__init__(mobject, introducer=True, **kwargs)
def create_target(self) -> Mobject:
return self.mobject
def create_starting_mobject(self) -> Mobject:
start = super().create_starting_mobject()
start.scale(0)
start.move_to(self.point)
if self.point_color:
start.set_color(self.point_color)
return start
[docs]class GrowFromCenter(GrowFromPoint):
"""Introduce an :class:`~.Mobject` by growing it from its center.
Parameters
----------
mobject
The mobjects to be introduced.
point_color
Initial color of the mobject before growing to its full size. Leave empty to match mobject's color.
Examples
--------
.. manim :: GrowFromCenterExample
class GrowFromCenterExample(Scene):
def construct(self):
squares = [Square() for _ in range(2)]
VGroup(*squares).set_x(0).arrange(buff=2)
self.play(GrowFromCenter(squares[0]))
self.play(GrowFromCenter(squares[1], point_color=RED))
"""
def __init__(self, mobject: Mobject, point_color: str = None, **kwargs) -> None:
point = mobject.get_center()
super().__init__(mobject, point, point_color=point_color, **kwargs)
[docs]class GrowFromEdge(GrowFromPoint):
"""Introduce an :class:`~.Mobject` by growing it from one of its bounding box edges.
Parameters
----------
mobject
The mobjects to be introduced.
edge
The direction to seek bounding box edge of mobject.
point_color
Initial color of the mobject before growing to its full size. Leave empty to match mobject's color.
Examples
--------
.. manim :: GrowFromEdgeExample
class GrowFromEdgeExample(Scene):
def construct(self):
squares = [Square() for _ in range(4)]
VGroup(*squares).set_x(0).arrange(buff=1)
self.play(GrowFromEdge(squares[0], DOWN))
self.play(GrowFromEdge(squares[1], RIGHT))
self.play(GrowFromEdge(squares[2], UR))
self.play(GrowFromEdge(squares[3], UP, point_color=RED))
"""
def __init__(
self, mobject: Mobject, edge: np.ndarray, point_color: str = None, **kwargs
) -> None:
point = mobject.get_critical_point(edge)
super().__init__(mobject, point, point_color=point_color, **kwargs)
[docs]class GrowArrow(GrowFromPoint):
"""Introduce an :class:`~.Arrow` by growing it from its start toward its tip.
Parameters
----------
arrow
The arrow to be introduced.
point_color
Initial color of the arrow before growing to its full size. Leave empty to match arrow's color.
Examples
--------
.. manim :: GrowArrowExample
class GrowArrowExample(Scene):
def construct(self):
arrows = [Arrow(2 * LEFT, 2 * RIGHT), Arrow(2 * DR, 2 * UL)]
VGroup(*arrows).set_x(0).arrange(buff=2)
self.play(GrowArrow(arrows[0]))
self.play(GrowArrow(arrows[1], point_color=RED))
"""
def __init__(self, arrow: Arrow, point_color: str = None, **kwargs) -> None:
point = arrow.get_start()
super().__init__(arrow, point, point_color=point_color, **kwargs)
def create_starting_mobject(self) -> Mobject:
start_arrow = self.mobject.copy()
start_arrow.scale(0, scale_tips=True, about_point=self.point)
if self.point_color:
start_arrow.set_color(self.point_color)
return start_arrow
[docs]class SpinInFromNothing(GrowFromCenter):
"""Introduce an :class:`~.Mobject` spinning and growing it from its center.
Parameters
----------
mobject
The mobjects to be introduced.
angle
The amount of spinning before mobject reaches its full size. E.g. 2*PI means
that the object will do one full spin before being fully introduced.
point_color
Initial color of the mobject before growing to its full size. Leave empty to match mobject's color.
Examples
--------
.. manim :: SpinInFromNothingExample
class SpinInFromNothingExample(Scene):
def construct(self):
squares = [Square() for _ in range(3)]
VGroup(*squares).set_x(0).arrange(buff=2)
self.play(SpinInFromNothing(squares[0]))
self.play(SpinInFromNothing(squares[1], angle=2 * PI))
self.play(SpinInFromNothing(squares[2], point_color=RED))
"""
def __init__(
self, mobject: Mobject, angle: float = PI / 2, point_color: str = None, **kwargs
) -> None:
self.angle = angle
super().__init__(
mobject, path_func=spiral_path(angle), point_color=point_color, **kwargs
)