import math
import random
import cv2
import numpy as np

TOTAL_OFFSET = 8

def gen_outline(path, dest):
    img = cv2.imread(path, cv2.IMREAD_GRAYSCALE)
    img_contour = cv2.imread(dest, cv2.IMREAD_UNCHANGED)

    kernel_size = 1
    sigma = 0.5
    kernel = cv2.getGaussianKernel(kernel_size, sigma)
    kernel = np.dot(kernel, kernel.T)
    smoothed = cv2.filter2D(img, -1, kernel)

    _, thresh = cv2.threshold(smoothed, 1, 255, cv2.THRESH_BINARY)
    contours, _ = cv2.findContours(thresh, cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_SIMPLE)

    # 计算轮廓的总面积
    total_area = 0
    for contour in contours:
        area = cv2.contourArea(contour)
        total_area = total_area + area

    # 选择周长和面积满足条件的轮廓，过滤太小的轮廓
    valid_contours = []
    threshold = 0.5
    idx = 0
    while not (len(valid_contours) > 0 and idx == 0):
        contour = contours[idx]
        perimeter = cv2.arcLength(contour, True)
        area = cv2.contourArea(contour)
        # print(path, "周长 =", perimeter, "面积占比 =", area/total_area, threshold)
        if perimeter > 0 and area/total_area > threshold:
            # print("add =====> ")
            valid_contours.append(contour)
        idx = idx + 1
        if idx >= len(contours):
            threshold = threshold - 0.1
            idx = 0

    start = random.randint(0, int(len(valid_contours[0])/3*2)-1)
    start = 0
    contour_points = valid_contours[0][start:(start + int(len(valid_contours[0])/3))]
    contour_points = valid_contours[0][start:(start + len(valid_contours[0]))]
    offset = (4, 4)
    offset_contour_points = contour_points + offset
    print("contour_points start = ", start, len(valid_contours[0]))
    cv2.polylines(img_contour, [offset_contour_points], False, (255, 255, 255, 255), int(TOTAL_OFFSET - 1), lineType=cv2.LINE_AA)
    cv2.polylines(img_contour, [offset_contour_points], False, (0, 0, 0, 255), int(TOTAL_OFFSET / 2 - 1), lineType=cv2.LINE_AA)
    
    # cv2.drawContours(img_contour, valid_contours, -1, (255, 255, 255, 255), 9, None, None, None, (5, 5))
    # cv2.drawContours(img_contour, valid_contours, -1, (0, 0, 0, 255), 5, None, None, None, (5, 5))
    # cv2.imwrite(dest, img_contour)

    cv2.imshow('Original Image', img)
    cv2.imshow('Contour Image', img_contour)
    cv2.waitKey(0)
    cv2.destroyAllWindows()

if __name__ == "__main__":
    gen_outline("./image.png", "./image-emt.png")