from base64 import b64decode, b64encode
import numpy as np
import cv2


def base64_to_np(img_data):
    img_data = img_data.split(',', 1)[-1]
    # b64decode -> base64图片解码
    # np.fromstring -> 从字符串中的文本数据初始化的新一维数组
    # numpy.fromstring(string, dtype=float, count=-1, sep='')
    return cv2.imdecode(np.fromstring(b64decode(img_data), dtype=np.uint8), cv2.IMREAD_COLOR)

def np_to_base64(np_data):
    img_str = cv2.imencode('.jpg', np_data)[1].tostring()
    return b64encode(img_str).decode('utf-8')