Chris@43: /* -*- c-basic-offset: 4 indent-tabs-mode: nil -*-  vi:set ts=8 sts=4 sw=4: */
Chris@43: 
Chris@43: /*
Chris@43:     Sonic Visualiser
Chris@43:     An audio file viewer and annotation editor.
Chris@43:     Centre for Digital Music, Queen Mary, University of London.
Chris@43:     This file copyright 2006 QMUL.
Chris@43:     
Chris@43:     This program is free software; you can redistribute it and/or
Chris@43:     modify it under the terms of the GNU General Public License as
Chris@43:     published by the Free Software Foundation; either version 2 of the
Chris@43:     License, or (at your option) any later version.  See the file
Chris@43:     COPYING included with this distribution for more information.
Chris@43: */
Chris@43: 
Chris@43: #include "PlaySpeedRangeMapper.h"
Chris@43: 
Chris@43: #include <iostream>
Chris@43: #include <cmath>
Chris@43: 
Chris@43: PlaySpeedRangeMapper::PlaySpeedRangeMapper(int minpos, int maxpos) :
Chris@43:     m_minpos(minpos),
Chris@43:     m_maxpos(maxpos)
Chris@43: {
Chris@43: }
Chris@43: 
Chris@43: int
Chris@43: PlaySpeedRangeMapper::getPositionForValue(float value) const
Chris@43: {
Chris@43:     // value is percent
Chris@43:     float factor = getFactorForValue(value);
Chris@43:     int position = getPositionForFactor(factor);
Chris@43:     return position;
Chris@43: }
Chris@43: 
Chris@43: int
Chris@43: PlaySpeedRangeMapper::getPositionForFactor(float factor) const
Chris@43: {
Chris@43:     bool slow = (factor > 1.0);
Chris@43: 
Chris@43:     if (!slow) factor = 1.0 / factor;
Chris@43:     
Chris@43:     int half = (m_maxpos + m_minpos) / 2;
Chris@43: 
Chris@43:     factor = sqrtf((factor - 1.0) * 1000.f);
Chris@43:     int position = lrintf(((factor * (half - m_minpos)) / 100.0) + m_minpos);
Chris@43: 
Chris@43:     if (slow) {
Chris@43:         position = half - position;
Chris@43:     } else {
Chris@43:         position = position + half;
Chris@43:     }
Chris@43: 
Chris@293: //    cerr << "value = " << value << " slow = " << slow << " factor = " << factor << " position = " << position << endl;
Chris@43: 
Chris@43:     return position;
Chris@43: }
Chris@43: 
Chris@43: float
Chris@43: PlaySpeedRangeMapper::getValueForPosition(int position) const
Chris@43: {
Chris@43:     float factor = getFactorForPosition(position);
Chris@43:     float pc = getValueForFactor(factor);
Chris@43:     return pc;
Chris@43: }
Chris@43: 
Chris@43: float
Chris@43: PlaySpeedRangeMapper::getValueForFactor(float factor) const
Chris@43: {
Chris@43:     float pc;
Chris@43:     if (factor < 1.0) pc = ((1.0 / factor) - 1.0) * 100.0;
Chris@43:     else pc = (1.0 - factor) * 100.0;
Chris@293: //    cerr << "position = " << position << " percent = " << pc << endl;
Chris@43:     return pc;
Chris@43: }
Chris@43: 
Chris@43: float
Chris@43: PlaySpeedRangeMapper::getFactorForValue(float value) const
Chris@43: {
Chris@43:     // value is percent
Chris@43:     
Chris@43:     float factor;
Chris@43: 
Chris@43:     if (value <= 0) {
Chris@43:         factor = 1.0 - (value / 100.0);
Chris@43:     } else {
Chris@43:         factor = 1.0 / (1.0 + (value / 100.0));
Chris@43:     }
Chris@43: 
Chris@293: //    cerr << "value = " << value << " factor = " << factor << endl;
Chris@43:     return factor;
Chris@43: }
Chris@43: 
Chris@43: float
Chris@43: PlaySpeedRangeMapper::getFactorForPosition(int position) const
Chris@43: {
Chris@43:     bool slow = false;
Chris@43: 
Chris@43:     if (position < m_minpos) position = m_minpos;
Chris@43:     if (position > m_maxpos) position = m_maxpos;
Chris@43: 
Chris@43:     int half = (m_maxpos + m_minpos) / 2;
Chris@43: 
Chris@43:     if (position < half) {
Chris@43:         slow = true;
Chris@43:         position = half - position;
Chris@43:     } else {
Chris@43:         position = position - half;
Chris@43:     }
Chris@43: 
Chris@43:     // position is between min and half (inclusive)
Chris@43: 
Chris@43:     float factor;
Chris@43: 
Chris@43:     if (position == m_minpos) {
Chris@43:         factor = 1.0;
Chris@43:     } else {
Chris@43:         factor = ((position - m_minpos) * 100.0) / (half - m_minpos);
Chris@43:         factor = 1.0 + (factor * factor) / 1000.f;
Chris@43:     }
Chris@43: 
Chris@43:     if (!slow) factor = 1.0 / factor;
Chris@43: 
Chris@293: //    cerr << "position = " << position << " slow = " << slow << " factor = " << factor << endl;
Chris@43: 
Chris@43:     return factor;
Chris@43: }
Chris@43: 
Chris@43: QString
Chris@43: PlaySpeedRangeMapper::getUnit() const
Chris@43: {
Chris@43:     return "%";
Chris@43: }