【manim】3b1b的"Almost" Fourier Transform复刻

最近在做Fourier Transform的内容，顺手记录一下一个下午的成果。

图像代码部分原理很简单，就是极坐标参数方程的转化。

原视频：https://www.youtube.com/watch?v=spUNpyF58BY&t=188s

bilibili：<iframe allowfullscreen="allowfullscreen" frameborder="no" height="277" scrolling="no" src="//player.bilibili.com/player.html?aid=19141078&bvid=BV1pW411J7s8&cid=31220967&page=1" style="width: 554px; height: 277px" width="554"> </iframe>

https://www.bilibili.com/video/BV1pW411J7s8?share_source=copy_web

数学公式在geogebra中构建如下：

manim代码：

from manim import *
class FourierTrans_First(Scene):
    def construct(self):
        axes = Axes(
            x_range=[-0, 2*PI, PI/4],
            y_range=[-0.1, 2.5, 1],
            x_length=14,
            y_length=2
            ).to_edge(UP)
        axes_label = axes.get_axis_labels('Time','Intensity')
        self.add(axes,axes_label)
        polarPlane = PolarPlane(
            radius_max=2.0,
            #azimuth_units="PI radians",
            azimuth_units="TAU radians",
            size=4,
            azimuth_label_font_size=24,
            radius_config={"font_size": 24},
        ).add_coordinates().to_edge(DOWN+LEFT)
        self.add(polarPlane)

        #一些全局参数
        delta = 0
        rou = 1
        move = 5
        dn_kwargs = {
            'show_ellipsis':False,
            'num_decimal_places':3,
            'include_sign':False,
            #"unit": r"^\circ",
            }
        D_delta = DecimalNumber(delta,**dn_kwargs)
        D_rou = DecimalNumber(rou,**dn_kwargs)
        D_move = DecimalNumber(move,**dn_kwargs).shift(DOWN)
        #解析式
        raw = lambda t: np.sin(t) + 1
        r = lambda t: np.sin(D_rou.get_value()*t+D_delta.get_value()) +1
        par = lambda t: np.array([
            r(t)*np.cos(D_move.get_value()*t),
            r(t)*np.sin(D_move.get_value()*t),
            0])
        #更新函数
        def Func_axes():
            return axes.plot(r,color=ORANGE)
    
        def Func_polar():
            return polarPlane.plot_polar_graph(r, [0, 2 * PI], color=ORANGE)

        def Func_para():
            return ParametricFunction(
                par
                , t_range = np.array([0, 3.14*2])
                , fill_opacity=0)\
                .set_color(color=[RED,YELLOW,BLUE,RED])\
                .to_edge(DOWN+RIGHT)

        axes_graph = Func_axes()
        polar_graph = Func_polar()
        para_graph = Func_para()

        axes_graph.add_updater(lambda mob: mob.become(Func_axes()))
        polar_graph.add_updater(lambda mob: mob.become(Func_polar()))
        para_graph.add_updater(lambda mob:mob.become(Func_para()))

        self.add(D_rou,D_move)
        self.play(Write(axes_graph),Write(polar_graph),Write(para_graph))
        self.play(ChangeDecimalToValue(D_rou,15),run_time=10,rate_func=linear)
        self.play(ChangeDecimalToValue(D_move,15),run_time=10,rate_func=linear)
        self.wait(1)

标签：move,3b1b,Almost,graph,self,axes,add,Func,复刻
来源： https://www.cnblogs.com/remyuu/p/16471751.html