import numpy as np
import cv2


def my_roberts(slika):
    kernalX = np.array([[1,0],[0,-1]])
    kernalY = np.array([[0,1],[-1,0]])

    slika_robov = np.zeros(slika.shape)

    height, width = slika.shape

    for y in range(0, height-2):
        for x in range(0, width-2):

            subImg = slika[y:y+2, x:x+2]
            kernalResultX = np.sum(kernalX * subImg)
            kernalResultY = np.sum(kernalY * subImg)

            kernalResult = np.absolute( kernalResultX ) + np.absolute( kernalResultY )
            slika_robov[y, x] = kernalResult

    slika_robov = np.uint8(slika_robov)
    return slika_robov

def my_prewitt(slika):
    kernalX = np.array([[-1, -1, -1], [0, 0, 0], [1, 1, 1]])
    kernalY = np.array([[-1, 0, 1], [-1, 0, 1], [-1, 0, 1]])

    slika_robov = np.zeros(slika.shape)

    height, width = slika.shape

    for y in range(1, height-2):
        for x in range(1, width-2):

            subImg = slika[y-1:y+2, x-1:x+2]
            kernalResultX = np.sum(kernalX * subImg)
            kernalResultY = np.sum(kernalY * subImg)

            kernalResult = np.absolute( kernalResultX ) + np.absolute( kernalResultY )
            slika_robov[y, x] = np.absolute(kernalResult)


    slika_robov = np.uint8(slika_robov)
    return slika_robov

def my_sobel(slika):
    kernalX = np.array([[-1, -3, -1], [0, 0, 0], [1, 3, 1]])
    kernalY = np.array([[-1, 0, 1], [-3, 0, 3], [-1, 0, 1]])

    slika_robov = np.zeros(slika.shape)

    height, width = slika.shape

    for y in range(1, height-2):
        for x in range(1, width-2):

            subImg = slika[y-1:y+2, x-1:x+2]
            kernalResultX = np.sum(kernalX * subImg)
            kernalResultY = np.sum(kernalY * subImg)

            kernalResult = np.absolute( kernalResultX ) + np.absolute( kernalResultY )
            slika_robov[y, x] = np.absolute(kernalResult)


    slika_robov = np.uint8(slika_robov)
    return slika_robov

def canny(slika):
    slika_robov = cv2.Canny(slika, 0, 0)
    return slika_robov

def spremeni_kontrast(slika, alfa, beta):
    return cv2.convertScaleAbs(slika, alpha=alfa, beta=beta)

img = cv2.imread('lenna.png', 0)
cv2.imshow('lenna', img)
#
#imgRoberts = my_roberts(img)
#cv2.imshow('lenna_roberts', imgRoberts)
#
#imgPrewitt = my_prewitt(img)
#cv2.imshow('lenna_prewitt', imgPrewitt)
#
#imgSobel = my_sobel(img)
#cv2.imshow('lenna_sobel', imgSobel)

img2 = spremeni_kontrast(img, 1.5, 0)
cv2.imshow('lenna2i', img2)
cv2.imshow('lenna2', my_sobel(img2))

img3 = spremeni_kontrast(img, 0.5, 1)
cv2.imshow('lenna3i', img3)
cv2.imshow('lenna3', my_sobel(img3))

windowName = 'lenna_canny'
val1 = 0
val2 = 0
def on_change1(val):
    global val1
    val1 = val
    imgCanny = cv2.Canny(img, val1, val2)
    cv2.imshow(windowName, imgCanny)

def on_change2(val):
    global val2
    val2 = val
    imgCanny = cv2.Canny(img, val1, val2)
    cv2.imshow(windowName, imgCanny)

imgCanny = canny(img)
cv2.imshow(windowName, imgCanny)
cv2.createTrackbar('threshold1', windowName, 0, 255, on_change1)
cv2.createTrackbar('threshold2', windowName, 0, 255, on_change2)

cv2.waitKey(0)
cv2.destroyAllWindows()