python - 如何在 python 中将 RGB 转换为 CMYK，反之亦然？

Question

如果我有一个 RGB 小数，例如 255, 165, 0，我该怎么做才能将其转换为 CMYK？

例如:

>>> red, green, blue = 255, 165, 0
>>> rgb_to_cmyk(red, green, blue)
(0, 35, 100, 0)

Answer 1

这是 Javascript implementation 的 Python 端口.

RGB_SCALE = 255
CMYK_SCALE = 100


def rgb_to_cmyk(r, g, b):
    if (r, g, b) == (0, 0, 0):
        # black
        return 0, 0, 0, CMYK_SCALE

    # rgb [0,255] -> cmy [0,1]
    c = 1 - r / RGB_SCALE
    m = 1 - g / RGB_SCALE
    y = 1 - b / RGB_SCALE

    # extract out k [0, 1]
    min_cmy = min(c, m, y)
    c = (c - min_cmy) / (1 - min_cmy)
    m = (m - min_cmy) / (1 - min_cmy)
    y = (y - min_cmy) / (1 - min_cmy)
    k = min_cmy

    # rescale to the range [0,CMYK_SCALE]
    return c * CMYK_SCALE, m * CMYK_SCALE, y * CMYK_SCALE, k * CMYK_SCALE