Source code for colour.models.rgb.transfer_functions.gopro

"""
GoPro Encoding
==============

Defines the *GoPro* *Protune* encoding:

-   :func:`colour.models.log_encoding_Protune`
-   :func:`colour.models.log_decoding_Protune`

References
----------
-   :cite:`GoPro2016a` : GoPro, Duiker, H.-P., & Mansencal, T. (2016).
    gopro.py. Retrieved April 12, 2017, from
    https://github.com/hpd/OpenColorIO-Configs/blob/master/aces_1.0.3/python/\
aces_ocio/colorspaces/gopro.py
"""

from __future__ import annotations

import numpy as np

from colour.hints import ArrayLike, NDArrayFloat
from colour.utilities import as_float, from_range_1, to_domain_1

__author__ = "Colour Developers"
__copyright__ = "Copyright 2013 Colour Developers"
__license__ = "BSD-3-Clause - https://opensource.org/licenses/BSD-3-Clause"
__maintainer__ = "Colour Developers"
__email__ = "colour-developers@colour-science.org"
__status__ = "Production"

__all__ = [
    "log_encoding_Protune",
    "log_decoding_Protune",
]


[docs] def log_encoding_Protune(x: ArrayLike) -> NDArrayFloat: """ Define the *Protune* log encoding curve / opto-electronic transfer function. Parameters ---------- x Linear data :math:`x`. Returns ------- :class:`numpy.ndarray` Non-linear data :math:`y`. Notes ----- +------------+-----------------------+---------------+ | **Domain** | **Scale - Reference** | **Scale - 1** | +============+=======================+===============+ | ``x`` | [0, 1] | [0, 1] | +------------+-----------------------+---------------+ +------------+-----------------------+---------------+ | **Range** | **Scale - Reference** | **Scale - 1** | +============+=======================+===============+ | ``y`` | [0, 1] | [0, 1] | +------------+-----------------------+---------------+ References ---------- :cite:`GoPro2016a` Examples -------- >>> log_encoding_Protune(0.18) # doctest: +ELLIPSIS 0.6456234... """ x = to_domain_1(x) y = np.log1p(x * 112) / np.log(113) return as_float(from_range_1(y))
[docs] def log_decoding_Protune(y: ArrayLike) -> NDArrayFloat: """ Define the *Protune* log decoding curve / electro-optical transfer function. Parameters ---------- y Non-linear data :math:`y`. Returns ------- :class:`numpy.ndarray` Linear data :math:`x`. Notes ----- +------------+-----------------------+---------------+ | **Domain** | **Scale - Reference** | **Scale - 1** | +============+=======================+===============+ | ``y`` | [0, 1] | [0, 1] | +------------+-----------------------+---------------+ +------------+-----------------------+---------------+ | **Range** | **Scale - Reference** | **Scale - 1** | +============+=======================+===============+ | ``x`` | [0, 1] | [0, 1] | +------------+-----------------------+---------------+ References ---------- :cite:`GoPro2016a` Examples -------- >>> log_decoding_Protune(0.645623486803636) # doctest: +ELLIPSIS 0.1... """ y = to_domain_1(y) x = (113**y - 1) / 112 return as_float(from_range_1(x))