# inspired by this post https://stackoverflow.com/a/65677170/4876516 by https://stackoverflow.com/users/334346/oleg

import numpy as np
import cv2 as cv

def stack_images(img_list, how, fill_color):
    max_height, max_width = 0, 0
    padding = 200  # 200
    total_height, total_width = padding, padding  # padding
    mult_by = 0 if fill_color == 'black' else 255

    for image in img_list:

        img_height, img_width = image.shape[0], image.shape[1]  

        if img_height > max_height:
            max_height = img_height
        total_width += img_width

        if img_width > max_width:
            max_width = img_width
        total_height += img_height

    final_image = None

    if how == 'ver':

        # create a new array with a size large enough to contain all the images with white pixels
        final_image = np.ones((total_height, max_width, 3), dtype=np.uint8)*mult_by

        curr_y = 0  # keep track of where your current image was last placed in the y coordinate
        for curr_image in img_list:

            img_height, img_width  = curr_image.shape[0], curr_image.shape[1]
            curr_height = curr_y + img_height
            calc_width =  max_width - img_width

            # add an image to the final array and increment the y coordinate
            curr_image = np.hstack((curr_image, np.ones((img_height, calc_width , 3))*mult_by))  # with white pixels
            # place current image
            final_image[curr_y:  curr_height, :, :] = curr_image
            curr_y += img_height

    elif how == 'hor':

        # create a new array with a size large enough to contain all the images with white pixels
        final_image = np.ones((max_height,total_width,  3), dtype=np.uint8)*mult_by

        curr_x = 0  # keep track of where your current image was last placed in the x coordinate
        for curr_image in img_list:

            img_height, img_width  = curr_image.shape[0], curr_image.shape[1]
            curr_width = curr_x + img_width
            calc_height =  max_height - img_height

            # add an image to the final array and increment the y coordinate
            curr_image = np.vstack((curr_image, np.ones((calc_height, img_width,  3))*mult_by))  # with white pixels
            # place current image
            final_image[:, curr_x:  curr_width,:] = curr_image
            curr_x += img_width

    return final_image


# cv.imwrite("test.png",stack_images([cv.imread("2ScreenTop.png"),cv.imread("2ScreenParallel.png")], 'hor', 'white'))