Padding Image with Python

pad_image.py

import cv2
import glob
import os
import tqdm
from itertools import islice
from multiprocessing import Pool
import numpy as np
from pathlib import Path

path = r'/path/to/image/*.png'
wanted_multiple = (4, 4) # Height, Width / Pad image to image size be multiple of wanted_multiple
origin_size = (240, 426) # Height, Width
output_dir = 'output'
pad_mode = True # True: padding / False: remove padding with origin_size

def pad_image(_file):
    img = cv2.imread(_file, cv2.IMREAD_UNCHANGED)
    if pad_mode:
        pad = ((0, (-1 * img.shape[0]) % wanted_multiple[0]), (0, (-1 * img.shape[1]) % wanted_multiple[1]), (0, 0))
        output_image = np.pad(img, pad, 'constant')
    else:
        output_image = img[:origin_size[0], :origin_size[1], :]
    save_path = os.path.join(os.path.dirname(_file), output_dir, os.path.basename(_file))
    Path(os.path.dirname(save_path)).mkdir(parents=True, exist_ok=True)
    cv2.imwrite(save_path, output_image)

if __name__ == '__main__':
    num_process = 16
    files = glob.glob(path, recursive=True)
    # iter_files = iter(files)
    # files = [list(islice(iter_files, e)) for e in [len(files) // num_process] * (num_process + 1)]
    # os.mkdir(os.path.join(os.path.dirname(path), output_dir))
    with Pool(processes=num_process) as p:
        r = list(tqdm.tqdm(p.imap(pad_image, files), total=len(files)))