2 Copyright (C) 2012-2014 Carl Hetherington <cth@carlh.net>
4 This program is free software; you can redistribute it and/or modify
5 it under the terms of the GNU General Public License as published by
6 the Free Software Foundation; either version 2 of the License, or
7 (at your option) any later version.
9 This program is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 GNU General Public License for more details.
14 You should have received a copy of the GNU General Public License
15 along with this program; if not, write to the Free Software
16 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
20 /** @file src/modified_gamma_transfer_function.h
21 * @brief ModifiedGammaTransferFunction class.
24 #include "transfer_function.h"
28 /** A transfer function which for an input x gives a linear output y where
30 * y = x / B for x <= threshold
31 * y = ((x + A) / (1 + A))^power for x > threshold
33 * The reverse transform is
35 * x = y * B for y <= threshold / B
36 * x = (1 + A) * y ^ (1 / power) - A for y > threshold / B
38 class ModifiedGammaTransferFunction : public TransferFunction
41 ModifiedGammaTransferFunction (double power, double threshold, double A, double B);
43 double power () const {
47 double threshold () const {
59 bool about_equal (boost::shared_ptr<const TransferFunction>, double epsilon) const;
62 double * make_lut (int bit_depth, bool inverse) const;