將matpoltlib繪製好的圖片從內存中取出

import matplotlib.pyplot as plt
import numpy as np
import io
from PIL import Image
import cv2
    fig = plt.figure("Image", frameon=False)# 圖像窗口名稱
    canvas = fig.canvas#關鍵
    name_list = ['0', "1", "2", "3", "4", "5", "6"]
    num_list = [round(random.random() * 100, 2), round(random.random() * 100, 2), round(random.random() * 100, 2),
                round(random.random() * 100, 2), round(random.random() * 100, 2), round(random.random() * 100, 2),
                round(random.random() * 100, 2)]
    rects = plt.bar(range(len(num_list)), num_list, color='rgby')
    index = [0, 1, 2, 3, 4, 5, 6]
    index = [float(c) for c in index]
    plt.ylim(ymax=110, ymin=0)
    plt.xticks(index, name_list)
    plt.ylabel("arrucay(%)")  # X軸標籤
    for rect in rects:
        height = rect.get_height()
        plt.text(rect.get_x() + rect.get_width() / 2, height, str(height) + '%', ha='center', va='bottom')
  
  
  #關鍵
    buffer = io.BytesIO()# 獲取輸入輸出流對象
    canvas.print_png(buffer)# 將畫布上的內容打印到輸入輸出流對象
    data = buffer.getvalue()# 獲取流的值
    # print("plt的二進制流爲:\n", data)
    buffer.write(data)# 將數據寫入buffer
    img = Image.open(buffer)# 使用Image打開圖片數據
    img = np.asarray(img)
    print("轉換的圖片array的尺寸爲:\n", img.shape)
    # print("轉換的圖片array爲:\n", img)
    cv2.imwrite("02.jpg", img)
    buffer.close()

其中標註爲關鍵字樣的地方最爲重要