import cv2 as cv
import numpy as np

def edge_demo(image):
    blurred = cv.GaussianBlur(image, (3, 3), 0)
    gray = cv.cvtColor(blurred, cv.COLOR_BGR2GRAY)
    edge_output = cv.Canny(gray, 30, 100)
    cv.imshow("Canny Edge", edge_output)
    return edge_output

def edge_contours_demo(image):
    binary = edge_demo(image)
    cv.imshow("canny binary", binary)

    cloneImage, contours, heriachy = cv.findContours(binary, cv.RETR_EXTERNAL, cv.CHAIN_APPROX_SIMPLE)
    for i, contour in enumerate(contours):
        cv.drawContours(image, contours, i, (0, 0, 255), 2)#最后一个参数为-1时表示填充
        approxCurve = cv.approxPolyDP(contour, 4, True)
        if approxCurve.shape[0] > 6:
            cv.drawContours(image, contours, i, (255, 0, 0), 2)
        if approxCurve.shape[0] == 4:
            cv.drawContours(image, contours, i, (0, 255, 0), 2)
        #print(approxCurve.shape[0])
        #print(i)
    cv.imshow("edge detect contours", image)

def contours_demo(image):
    dst = cv.GaussianBlur(image, (3, 3), 0)
    gray = cv.cvtColor(dst, cv.COLOR_BGR2GRAY)
    ret, binary = cv.threshold(gray, 0, 255, cv.THRESH_BINARY | cv.THRESH_OTSU)
    cv.imshow("binary image", binary)
   # binary = edge_demo(image)

    cloneImage, contours, heriachy = cv.findContours(binary, cv.RETR_EXTERNAL, cv.CHAIN_APPROX_SIMPLE)
    for i, contour in enumerate(contours):
        cv.drawContours(image, contours, i, (0, 0, 255), 2)#最后一个参数为-1时表示填充
        approxCurve = cv.approxPolyDP(contour, 4, True)
        if approxCurve.shape[0] > 6:
            cv.drawContours(image, contours, i, (255, 0, 0), 2)
        if approxCurve.shape[0] == 4:
            cv.drawContours(image, contours, i, (0, 255, 0), 2)
        #print(approxCurve.shape[0])
        #print(i)
    cv.imshow("detect contours", image)

src = cv.imread("3.png")

cv.namedWindow("input image", cv.WINDOW_AUTOSIZE)
cv.imshow("input image", src)
src1=src.copy()
src2=src.copy()

contours_demo(src1)
edge_contours_demo(src2)

cv.waitKey(0)

cv.destroyAllWindows()