如何将matplotlib输出添加到视频

import matplotlib.pyplot as plt
import cv2
import numpy as np

fourcc = cv2.VideoWriter_fourcc(*'mp4v')  # 视频编码格式
video_writer = cv2.VideoWriter('output.mp4', fourcc, 30, (640, 480))  # 输出视频文件名、编码格式、帧率、分辨率

for i in range(100):  # 生成100帧图像
    # 创建matplotlib图形
    fig, ax = plt.subplots()
    ax.plot([0, i], [0, i**2])  # 示例：绘制一条直线

    # 将matplotlib图形转换为OpenCV图像
    fig.canvas.draw()
    img = np.array(fig.canvas.renderer.buffer_rgba())

    # 调整图像尺寸以适应视频分辨率
    img = cv2.resize(img, (640, 480))

    # 将图像写入视频
    video_writer.write(img)

    # 清除matplotlib图形以便下一帧的绘制
    plt.close(fig)

video_writer.release()