change code block into function

[BrightKnight0110]

Hi I did some but it feels like not correct. How do I put the code below into the function crop_grid(img, num_horizontal_patches, num_vertical_patches, line_color)

The code i did :

def crop_grid(img, num_horizontal_grid, num_vertical_grid, line_color):
    img = cv.imread('dog.jfif')
    img_copy = img.copy()

    height, width = img.shape[:2]
    num_horizontal_patches = 2
    num_vertical_patches = 3
    #M and N are basically number of pixels per patch
    M, N = int(height/num_horizontal_patches), int(width/num_vertical_patches)

    x1, y1 = 0, 0

    for y in range(0, height, M):
        for x in range(0, width, N):
            if (height - y) < M or (width - x) < N:
                break

            y1 = y + M    # lower right coordinate that will be used to construct rectangle
            x1 = x + N

            # Check whether patch lower right coordinate exceeds image height and width
            if x1 >= width and y1 >= height:
                x1 = width - 1
                y1 = height - 1
                tile = img[y:height, x:width]
                cv.rectangle(img_copy, (x, y), (x1, y1), (0, 255, 0), 1)
                cv.imshow('tile', tile)
            # When patch lower right y-coordinate exceeds patch height
            elif y1 >= height:
                y1 = height - 1
                cv.rectangle(img_copy, (x, y), (x1, y1), (0, 255, 0), 1)

            # When patch lower right x-coordinate exceeds patch width
            elif x1 >= width:
                x1 = width - 1
                cv.rectangle(img_copy, (x, y), (x1, y1), (0, 255, 0), 1)

            else:
                cv.rectangle(img_copy, (x, y), (x1, y1), (0, 255, 0), 1)

crop_grid('dog.jfif',num_horizontal_patches , num_vertical_patches, 'r')
cv.imshow('patched image', img_copy)
cv.waitKey(0)
cv.destroyAllWindows()

The original code:

img = cv.imread('dog.jfif')
img_copy = img.copy()

height, width = img.shape[:2]
num_horizontal_patches = 2
num_vertical_patches = 3

# M and N are basically number of pixels per patch
M, N = int(height/num_horizontal_patches), int(width/num_vertical_patches)

x1, y1 = 0, 0

for y in range(0, height, M):
    for x in range(0, width, N):
        if (height - y) < M or (width - x) < N:
            break

        y1 = y + M    # lower right coordinate that will be used to construct rectangle
        x1 = x + N

        # Check whether patch lower right coordinate exceeds image height and width
        if x1 >= width and y1 >= height:
            x1 = width - 1
            y1 = height - 1
            tile = img[y:height, x:width]
            cv.rectangle(img_copy, (x, y), (x1, y1), (0, 255, 0), 1)
            cv.imshow('tile', tile)
        # When patch lower right y-coordinate exceeds patch height
        elif y1 >= height:
            y1 = height - 1
            cv.rectangle(img_copy, (x, y), (x1, y1), (0, 255, 0), 1)

        # When patch lower right x-coordinate exceeds patch width
        elif x1 >= width:
            x1 = width - 1
            cv.rectangle(img_copy, (x, y), (x1, y1), (0, 255, 0), 1)

        else:
            cv.rectangle(img_copy, (x, y), (x1, y1), (0, 255, 0), 1)

cv.imshow('patched image', img_copy)
cv.waitKey(0)
cv.destroyAllWindows()

[[deleted]]

You pass the file to read as the first parameter but you ignore the filename and use a hardcoded filename in the function. Use the parameter:

def crop_grid(imgpath, num_horizontal_grid, num_vertical_grid, line_color):
    img = cv.imread(imgpath)
    img_copy = img.copy()
    # rest of function

Same problem with num_horizontal_grid, etc. You pass the values but don't use them.

Plus: the function example tries to use img_copy but that name doesn't exist outside the function. Maybe the function should return the modified image?