3b1b-manim/manimlib/mobject/value_tracker.py
2022-12-16 10:02:12 -08:00

63 lines
1.7 KiB
Python

from __future__ import annotations
import numpy as np
from manimlib.mobject.mobject import Mobject
from manimlib.utils.iterables import listify
class ValueTracker(Mobject):
"""
Not meant to be displayed. Instead the position encodes some
number, often one which another animation or continual_animation
uses for its update function, and by treating it as a mobject it can
still be animated and manipulated just like anything else.
"""
value_type: type = np.float64
def __init__(
self,
value: float | complex | np.ndarray = 0,
**kwargs
):
self.value = value
super().__init__(**kwargs)
def init_data(self) -> None:
super().init_data()
self.data["value"] = np.array(
listify(self.value),
ndmin=2,
dtype=self.value_type,
)
def get_value(self) -> float | complex:
result = self.data["value"][0, :]
if len(result) == 1:
return result[0]
return result
def set_value(self, value: float | complex):
self.data["value"][0, :] = value
return self
def increment_value(self, d_value: float | complex) -> None:
self.set_value(self.get_value() + d_value)
class ExponentialValueTracker(ValueTracker):
"""
Operates just like ValueTracker, except it encodes the value as the
exponential of a position coordinate, which changes how interpolation
behaves
"""
def get_value(self) -> float | complex:
return np.exp(ValueTracker.get_value(self))
def set_value(self, value: float | complex):
return ValueTracker.set_value(self, np.log(value))
class ComplexValueTracker(ValueTracker):
value_type: type = np.complex128