#-*- coding:utf-8-*-

import cv2
import numpy as np

img = cv2.imread('../data/chess.jpg')
img_original = img.copy()

gray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)
edges = cv2.Canny(gray, 50, 150, apertureSize=3)

lines = cv2.HoughLines(edges, 1, np.pi / 180, 160)

for i in range(len(lines)):
    for rho, theta in lines[i]:
        a = np.cos(theta)
        b = np.sin(theta)
        x0 = a*rho
        y0 = b*rho
        x1 = int(x0 + 1000 * (-b))
        y1 = int(y0+1000 * (a))
        x2 = int(x0 - 1000 * (-b))
        y2 = int(y0 -1000 * (a))

        cv2.line(img, (x1, y1), (x2, y2), (0, 0, 255), 2)


cv2.imshow('img', img_original)
cv2.imshow('result', img)

if cv2.waitKey(0) & 0xff == 27:
    cv2.destroyAllWindows()
    
    