livetrax/libs/surfaces/tranzport/slider_gain.h

/*
 *   Copyright (C) 2006 Paul Davis
 *   Copyright (C) 2007 Michael Taht
 *
 *   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.
 *
 *   */

#ifndef ardour_slider_gain
#define ardour_slider_gain

static inline double
gain_to_slider_position (ARDOUR::gain_t g)
{
	if (g == 0) return 0;
	return pow((6.0*log(g)/log(2.0)+192.0)/198.0, 8.0);

}

static inline ARDOUR::gain_t
slider_position_to_gain (double pos)
{
	/* XXX Marcus writes: this doesn't seem right to me. but i don't have a better answer ... */
	if (pos == 0.0) return 0;
	return pow (2.0,(sqrt(sqrt(sqrt(pos)))*198.0-192.0)/6.0);
}

#endif