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livetrax/libs/surfaces/tranzport/slider_gain.h

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/*
* 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