contrast_c.pyx

# cython: language_level=3, boundscheck=False

import cv2
import math

cpdef unsigned char[:, :] adjust_contrast(unsigned char[:, :] img, float contrast):
    cdef int x, y, width, height
    height = img.shape[0]
    width = img.shape[1]
    for y in range(height):
        for x in range(width):
            b = math.ceil(img[y, x] * contrast)
            if b > 255:
                b = 255
            img[y, x] = b

    return img