manimの作法 その55

概要

manimの作法、調べてみた。
AnimatedStreamLines、使ってみた。

サンプルコード

from manimlib.imports import *

class test(Scene):
	CONFIG = {
		"vector_field_config": {
			"length_func": lambda norm: 0.1 + 0.4 * norm / 4.0,
			"min_magnitude": 0,
			"max_magnitude": 3,
		},
		"stream_lines_config": {
			"start_points_generator_config": {
			#	"delta_x": 0.125,
			#	"delta_y": 0.125,
			},
			"virtual_time": 1,
			"min_magnitude": 0,
			"max_magnitude": 3,
		},
	}
	def construct(self):
		def func(point):
			return 3 * sigmoid(point[0]) * RIGHT
		vector_field = self.vector_field = VectorField(func, **self.vector_field_config)
		circle = Circle(color = WHITE)
		slow_words = TextMobject("Slow flow in")
		fast_words = TextMobject("Fast flow out")
		words = VGroup(slow_words, fast_words)
		for word, vect in zip(words, [LEFT, RIGHT]):
			word.add_background_rectangle()
			word.next_to(circle, vect)
		div_tex = TexMobject("\\text{div}\\,\\textbf{F}(x, y) > 0")
		div_tex.add_background_rectangle()
		div_tex.next_to(circle, UP)
		self.add(vector_field)
		self.add_foreground_mobjects(circle, div_tex)
		self.begin_flow()
		self.wait(2)
		for word in words:
			self.add_foreground_mobjects(word)
			self.play(Write(word))
		self.wait(8)
	def begin_flow(self):
		stream_lines = StreamLines(self.vector_field.func, **self.stream_lines_config)
		stream_line_animation = AnimatedStreamLines(stream_lines)
		stream_line_animation.update(3)
		self.add(stream_line_animation)

生成した動画

https://www.youtube.com/watch?v=vvJ-pm1R_o8
以上。