/*
    Copyright (C) 2012-2014 Carl Hetherington <cth@carlh.net>

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

*/

/** @file  src/modified_gamma_transfer_function.h
 *  @brief ModifiedGammaTransferFunction class.
 */

#include "transfer_function.h"

namespace dcp {

/** A transfer function which for an input x gives an output y where
 *
 *  y = x / B                      for x <= threshold
 *  y = ((x + A) / (1 + A))^power  for x >  threshold
 */
class ModifiedGammaTransferFunction : public TransferFunction
{
public:
	ModifiedGammaTransferFunction (double power, double threshold, double A, double B);

	double power () const {
		return _power;
	}

	double threshold () const {
		return _threshold;
	}

	double A () const {
		return _A;
	}

	double B () const {
		return _B;
	}

	bool about_equal (boost::shared_ptr<const TransferFunction>, double epsilon) const;

protected:
	double * make_lut (int bit_depth, bool inverse) const;

private:
	double _power;
	double _threshold;
	double _A;
	double _B;
};

}