# -*- encoding:utf-8 -*-

'''
@Author : dingjiawen
@Date : 2023/12/11 20:59
@Usage : 
@Desc :
@参考：https://github.com/Python3WebSpider/CrackSlideCaptcha/blob/cv/main.py
'''

import cv2

GAUSSIAN_BLUR_KERNEL_SIZE = (5, 5)
GAUSSIAN_BLUR_SIGMA_X = 0
CANNY_THRESHOLD1 = 200
CANNY_THRESHOLD2 = 450


# 得到高斯滤波之后的图
def get_gaussian_blur_image(image):
    return cv2.GaussianBlur(image, GAUSSIAN_BLUR_KERNEL_SIZE, GAUSSIAN_BLUR_SIGMA_X)


# 得到边缘检测之后的图
def get_canny_image(image):
    return cv2.Canny(image, CANNY_THRESHOLD1, CANNY_THRESHOLD2)


# 得到轮廓信息，会保留比较明显的边缘信息
def get_contours(image):
    contours, _ = cv2.findContours(image, cv2.RETR_CCOMP, cv2.CHAIN_APPROX_SIMPLE)
    return contours


# 得到轮廓的上下限:
# 外接矩形的高度和宽度是通过实际测量得出来的，高约0.25，宽约0.15
# 缺口有一个最大偏移量和最小偏移量，最小偏移量是验证码宽度的0.2倍，最大是0.85倍

#面积阈值
def get_contour_area_threshold(image_width, image_height):
    contour_area_min = (image_width * 0.15) * (image_height * 0.25) * 0.8
    contour_area_max = (image_width * 0.15) * (image_height * 0.25) * 1.2
    return contour_area_min, contour_area_max

# 周长阈值
def get_arc_length_threshold(image_width, image_height):
    arc_length_min = ((image_width * 0.15) + (image_height * 0.25)) * 2 * 0.8
    arc_length_max = ((image_width * 0.15) + (image_height * 0.25)) * 2 * 1.2
    return arc_length_min, arc_length_max

# offset阈值
def get_offset_threshold(image_width):
    offset_min = 0.2 * image_width
    offset_max = 0.85 * image_width
    return offset_min, offset_max


def main():
    # 长,宽,channel
    image_raw = cv2.imread('captcha.png')
    image_height, image_width, _ = image_raw.shape
    image_gaussian_blur = get_gaussian_blur_image(image_raw)
    # 长，宽   黑白的没有channel
    image_canny = get_canny_image(image_gaussian_blur)
    contours = get_contours(image_canny)
    cv2.imwrite('image_canny.png', image_canny)
    cv2.imwrite('image_gaussian_blur.png', image_gaussian_blur)
    contour_area_min, contour_area_max = get_contour_area_threshold(image_width, image_height)
    arc_length_min, arc_length_max = get_arc_length_threshold(image_width, image_height)
    offset_min, offset_max = get_offset_threshold(image_width)
    offset = None
    for contour in contours:
        # 计算外接矩形的x,y起始点位置;w,h宽和高
        x, y, w, h = cv2.boundingRect(contour)
        if contour_area_min < cv2.contourArea(contour) < contour_area_max and \
                arc_length_min < cv2.arcLength(contour, True) < arc_length_max and \
                offset_min < x < offset_max:
            cv2.rectangle(image_raw, (x, y), (x + w, y + h), (0, 0, 255), 2)
            offset = x
    cv2.imwrite('image_label.png', image_raw)
    print('offset', offset)


if __name__ == '__main__':
    main()