2 Copyright (C) 2012-2014 Carl Hetherington <cth@carlh.net>
4 This file is part of libdcp.
6 libdcp is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 2 of the License, or
9 (at your option) any later version.
11 libdcp is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with libdcp. If not, see <http://www.gnu.org/licenses/>.
21 /** @file src/gamma_transfer_function.cc
22 * @brief GammaTransferFunction class.
25 #include "gamma_transfer_function.h"
29 using boost::shared_ptr;
30 using boost::dynamic_pointer_cast;
33 GammaTransferFunction::GammaTransferFunction (double gamma)
40 GammaTransferFunction::make_lut (int bit_depth, bool inverse) const
42 int const bit_length = int(std::pow(2.0f, bit_depth));
43 double* lut = new double[bit_length];
44 double const gamma = inverse ? (1 / _gamma) : _gamma;
45 for (int i = 0; i < bit_length; ++i) {
46 lut[i] = pow(double(i) / (bit_length - 1), gamma);
53 GammaTransferFunction::about_equal (shared_ptr<const TransferFunction> other, double epsilon) const
55 shared_ptr<const GammaTransferFunction> o = dynamic_pointer_cast<const GammaTransferFunction> (other);
60 return fabs (_gamma - o->_gamma) < epsilon;