import cv2
import numpy as np


def crop_img(image: "np.ndarray") -> "np.ndarray":
    gray = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)  # noqa 将图像转换为灰度图像
    _, threshold = cv2.threshold(gray, 150, 255, cv2.THRESH_BINARY)  # noqa 换为二值图像 => save: [150,255]
    contours, _ = cv2.findContours(threshold, cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_SIMPLE)  # noqa 查找轮廓
    max_contour = max(contours, key=cv2.contourArea)  # noqa 找到最大的轮廓
    rect = cv2.minAreaRect(max_contour)  # noqa 计算最小外接矩形
    box = cv2.boxPoints(rect)  # noqa 获取矩形的四个角点
    box = np.intp(box)
    # 裁剪图像
    return image[min(box[:, 1]):max(box[:, 1]), min(box[:, 0]):max(box[:, 0])]


def main():
    path = "img/11.jpg"
    cropped = crop_img(cv2.imread(path))  # noqa
    print(cropped.shape)
    cv2.imshow("cropped", cropped)  # noqa
    cv2.waitKey(0)  # noqa


if __name__ == '__main__':
    main()