lbajardsilogic@0: /* -*- c-basic-offset: 4 indent-tabs-mode: nil -*-  vi:set ts=8 sts=4 sw=4: */
lbajardsilogic@0: 
lbajardsilogic@0: /*
lbajardsilogic@0:     Sonic Visualiser
lbajardsilogic@0:     An audio file viewer and annotation editor.
lbajardsilogic@0:     Centre for Digital Music, Queen Mary, University of London.
lbajardsilogic@0:     This file copyright 2006 QMUL.
lbajardsilogic@0:     
lbajardsilogic@0:     This program is free software; you can redistribute it and/or
lbajardsilogic@0:     modify it under the terms of the GNU General Public License as
lbajardsilogic@0:     published by the Free Software Foundation; either version 2 of the
lbajardsilogic@0:     License, or (at your option) any later version.  See the file
lbajardsilogic@0:     COPYING included with this distribution for more information.
lbajardsilogic@0: */
lbajardsilogic@0: 
lbajardsilogic@0: #include "PlaySpeedRangeMapper.h"
lbajardsilogic@0: 
lbajardsilogic@0: #include <iostream>
lbajardsilogic@0: #include <cmath>
lbajardsilogic@0: 
lbajardsilogic@0: #include "system/System.h"
lbajardsilogic@0: 
lbajardsilogic@0: PlaySpeedRangeMapper::PlaySpeedRangeMapper(int minpos, int maxpos) :
lbajardsilogic@0:     m_minpos(minpos),
lbajardsilogic@0:     m_maxpos(maxpos)
lbajardsilogic@0: {
lbajardsilogic@0: }
lbajardsilogic@0: 
lbajardsilogic@0: int
lbajardsilogic@0: PlaySpeedRangeMapper::getPositionForValue(float value) const
lbajardsilogic@0: {
lbajardsilogic@0:     // value is percent
lbajardsilogic@0:     float factor = getFactorForValue(value);
lbajardsilogic@0:     int position = getPositionForFactor(factor);
lbajardsilogic@0:     return position;
lbajardsilogic@0: }
lbajardsilogic@0: 
lbajardsilogic@0: int
lbajardsilogic@0: PlaySpeedRangeMapper::getPositionForFactor(float factor) const
lbajardsilogic@0: {
lbajardsilogic@0:     bool slow = (factor > 1.0);
lbajardsilogic@0: 
lbajardsilogic@0:     if (!slow) factor = 1.0 / factor;
lbajardsilogic@0:     
lbajardsilogic@0:     int half = (m_maxpos + m_minpos) / 2;
lbajardsilogic@0: 
lbajardsilogic@0:     factor = sqrtf((factor - 1.0) * 1000.f);
lbajardsilogic@0:     int position = lrintf(((factor * (half - m_minpos)) / 100.0) + m_minpos);
lbajardsilogic@0: 
lbajardsilogic@0:     if (slow) {
lbajardsilogic@0:         position = half - position;
lbajardsilogic@0:     } else {
lbajardsilogic@0:         position = position + half;
lbajardsilogic@0:     }
lbajardsilogic@0: 
lbajardsilogic@0: //    std::cerr << "value = " << value << " slow = " << slow << " factor = " << factor << " position = " << position << std::endl;
lbajardsilogic@0: 
lbajardsilogic@0:     return position;
lbajardsilogic@0: }
lbajardsilogic@0: 
lbajardsilogic@0: float
lbajardsilogic@0: PlaySpeedRangeMapper::getValueForPosition(int position) const
lbajardsilogic@0: {
lbajardsilogic@0:     float factor = getFactorForPosition(position);
lbajardsilogic@0:     float pc = getValueForFactor(factor);
lbajardsilogic@0:     return pc;
lbajardsilogic@0: }
lbajardsilogic@0: 
lbajardsilogic@0: float
lbajardsilogic@0: PlaySpeedRangeMapper::getValueForFactor(float factor) const
lbajardsilogic@0: {
lbajardsilogic@0:     float pc;
lbajardsilogic@0:     if (factor < 1.0) pc = ((1.0 / factor) - 1.0) * 100.0;
lbajardsilogic@0:     else pc = (1.0 - factor) * 100.0;
lbajardsilogic@0: //    std::cerr << "position = " << position << " percent = " << pc << std::endl;
lbajardsilogic@0:     return pc;
lbajardsilogic@0: }
lbajardsilogic@0: 
lbajardsilogic@0: float
lbajardsilogic@0: PlaySpeedRangeMapper::getFactorForValue(float value) const
lbajardsilogic@0: {
lbajardsilogic@0:     // value is percent
lbajardsilogic@0:     
lbajardsilogic@0:     float factor;
lbajardsilogic@0: 
lbajardsilogic@0:     if (value <= 0) {
lbajardsilogic@0:         factor = 1.0 - (value / 100.0);
lbajardsilogic@0:     } else {
lbajardsilogic@0:         factor = 1.0 / (1.0 + (value / 100.0));
lbajardsilogic@0:     }
lbajardsilogic@0: 
lbajardsilogic@0: //    std::cerr << "value = " << value << " factor = " << factor << std::endl;
lbajardsilogic@0:     return factor;
lbajardsilogic@0: }
lbajardsilogic@0: 
lbajardsilogic@0: float
lbajardsilogic@0: PlaySpeedRangeMapper::getFactorForPosition(int position) const
lbajardsilogic@0: {
lbajardsilogic@0:     bool slow = false;
lbajardsilogic@0: 
lbajardsilogic@0:     if (position < m_minpos) position = m_minpos;
lbajardsilogic@0:     if (position > m_maxpos) position = m_maxpos;
lbajardsilogic@0: 
lbajardsilogic@0:     int half = (m_maxpos + m_minpos) / 2;
lbajardsilogic@0: 
lbajardsilogic@0:     if (position < half) {
lbajardsilogic@0:         slow = true;
lbajardsilogic@0:         position = half - position;
lbajardsilogic@0:     } else {
lbajardsilogic@0:         position = position - half;
lbajardsilogic@0:     }
lbajardsilogic@0: 
lbajardsilogic@0:     // position is between min and half (inclusive)
lbajardsilogic@0: 
lbajardsilogic@0:     float factor;
lbajardsilogic@0: 
lbajardsilogic@0:     if (position == m_minpos) {
lbajardsilogic@0:         factor = 1.0;
lbajardsilogic@0:     } else {
lbajardsilogic@0:         factor = ((position - m_minpos) * 100.0) / (half - m_minpos);
lbajardsilogic@0:         factor = 1.0 + (factor * factor) / 1000.f;
lbajardsilogic@0:     }
lbajardsilogic@0: 
lbajardsilogic@0:     if (!slow) factor = 1.0 / factor;
lbajardsilogic@0: 
lbajardsilogic@0: //    std::cerr << "position = " << position << " slow = " << slow << " factor = " << factor << std::endl;
lbajardsilogic@0: 
lbajardsilogic@0:     return factor;
lbajardsilogic@0: }
lbajardsilogic@0: 
lbajardsilogic@0: QString
lbajardsilogic@0: PlaySpeedRangeMapper::getUnit() const
lbajardsilogic@0: {
lbajardsilogic@0:     return "%";
lbajardsilogic@0: }