from multiprocessing import Pool
import cv2

import sys
from timeit import default_timer as timer


THRESH_METHOD = cv2.ADAPTIVE_THRESH_GAUSSIAN_C
INPUT_PATH = 'input/large_input/'
OUTPUT_PATH = 'output/large_output/'

n = 20
names = ['ship_%i_%i.jpg' % (i, j) for i in range(n) for j in range(n)]


def process_threshold(im, output_name, thresh_method):
    gray_im = cv2.cvtColor(im, cv2.COLOR_BGR2GRAY)
    thresh_im = cv2.adaptiveThreshold(gray_im, 255, thresh_method, cv2.THRESH_BINARY, 11, 2)

    cv2.imwrite(OUTPUT_PATH + output_name, thresh_im)


if __name__ == '__main__':

    for n_processes in range(1, 7):
        start = timer()

        with Pool(n_processes) as p:
            p.starmap(process_threshold, [(
                cv2.imread(INPUT_PATH + name),
                name,
                THRESH_METHOD
            ) for name in names])

        print('Took %.4f seconds with %i process(es).' % (timer() - start, n_processes))

    print('Done.')