QingLong/AI/Manim/L8_PolarGraph.py

import manim
from manim import *
import numpy as np


class PolarGraph(Scene):
    def construct(self):
        # 初始化参数跟踪器
        e = ValueTracker(0.01)

        # ===== 极坐标系部分 =====
        # 修正1：使用PolarPlane的正确拼写
        polar_plane = PolarPlane(
            radius_max=3,
            azimuth_step=6  # 极角刻度间隔（单位：度）
        ).add_coordinates().shift(LEFT * 2)

        # 修正2：使用正确的参数方程
        polar_graph = always_redraw(
            lambda: ParametricFunction(
                lambda t: polar_plane.polar_to_point(2 * np.sin(3 * t), t),
                t_range=[0, e.get_value()],
                color=GREEN
            )
        )

        polar_dot = always_redraw(
            lambda: Dot(
                color=GREEN,
                radius=0.08
            ).move_to(polar_graph.get_end())
        )

        # ===== 直角坐标系部分 =====
        axes = Axes(
            x_range=[0, 4, 1],
            y_range=[-3, 3, 1],
            x_length=3,
            y_length=3,
            axis_config={"color": BLUE}
        ).shift(RIGHT * 4)
        axes.add_coordinates()

        cartesian_graph = always_redraw(
            lambda: axes.plot(
                lambda x: 2 * np.sin(3 * x),
                x_range=[0, e.get_value()],
                color=GREEN
            )
        )

        cartesian_dot = always_redraw(
            lambda: Dot(
                color=GREEN,
                radius=0.08
            ).move_to(cartesian_graph.get_end())
        )

        # 公式标签
        title = MathTex(r"f(\theta) = 2\sin(3\theta)", color=GREEN).next_to(axes, UP)

        # ===== 动画序列 =====
        # 修正3：正确拼写LaggedStart
        self.play(
            LaggedStart(
                Create(polar_plane),
                Create(axes),
                Write(title),
                lag_ratio=0.5
            ),
            run_time=3
        )

        self.add(polar_graph, cartesian_graph, polar_dot, cartesian_dot)

        # 参数变化动画
        self.play(
            e.animate.set_value(PI),
            run_time=10,
            rate_func=linear
        )
        self.wait()

if __name__ == '__main__':
    config = {
        "quality": "low_quality",
        "preview": True,
        "media_dir": "./output"
    }

    with manim.tempconfig(config):
        scene = PolarGraph()
        scene.render()