Chris@59: /* -*- c-basic-offset: 4 indent-tabs-mode: nil -*-  vi:set ts=8 sts=4 sw=4: */
Chris@59: 
Chris@59: /*
Chris@59:     Sonic Visualiser
Chris@59:     An audio file viewer and annotation editor.
Chris@59:     Centre for Digital Music, Queen Mary, University of London.
Chris@59:     This file copyright 2006 Chris Cannam.
Chris@59:     
Chris@59:     This program is free software; you can redistribute it and/or
Chris@59:     modify it under the terms of the GNU General Public License as
Chris@59:     published by the Free Software Foundation; either version 2 of the
Chris@59:     License, or (at your option) any later version.  See the file
Chris@59:     COPYING included with this distribution for more information.
Chris@59: */
Chris@59: 
Chris@59: #include "PlaySpeedRangeMapper.h"
Chris@59: 
Chris@59: #include <iostream>
Chris@59: 
Chris@59: 
Chris@59: PlaySpeedRangeMapper::PlaySpeedRangeMapper(int minpos, int maxpos) :
Chris@59:     m_minpos(minpos),
Chris@59:     m_maxpos(maxpos)
Chris@59: {
Chris@59: }
Chris@59: 
Chris@59: int
Chris@59: PlaySpeedRangeMapper::getPositionForValue(float value) const
Chris@59: {
Chris@59:     // value is percent
Chris@59: 
Chris@59:     float factor = getFactorForValue(value);
Chris@59: 
Chris@59:     bool slow = (factor > 1.0);
Chris@59: 
Chris@59:     if (!slow) factor = 1.0 / factor;
Chris@59:     
Chris@59:     int half = (m_maxpos + m_minpos) / 2;
Chris@59: 
Chris@59:     factor = sqrtf((factor - 1.0) * 1000.f);
Chris@59:     int position = lrintf(((factor * (half - m_minpos)) / 100.0) + m_minpos);
Chris@59: 
Chris@59:     if (slow) {
Chris@59:         position = half - position;
Chris@59:     } else {
Chris@59:         position = position + half;
Chris@59:     }
Chris@59: 
Chris@59: //    std::cerr << "value = " << value << " slow = " << slow << " factor = " << factor << " position = " << position << std::endl;
Chris@59: 
Chris@59:     return position;
Chris@59: }
Chris@59: 
Chris@59: float
Chris@59: PlaySpeedRangeMapper::getValueForPosition(int position) const
Chris@59: {
Chris@59:     float factor = getFactorForPosition(position);
Chris@59:     float pc;
Chris@59:     if (factor < 1.0) pc = ((1.0 / factor) - 1.0) * 100.0;
Chris@59:     else pc = (1.0 - factor) * 100.0;
Chris@59: //    std::cerr << "position = " << position << " percent = " << pc << std::endl;
Chris@59:     return pc;
Chris@59: }
Chris@59: 
Chris@59: float
Chris@59: PlaySpeedRangeMapper::getFactorForValue(float value) const
Chris@59: {
Chris@59:     // value is percent
Chris@59:     
Chris@59:     float factor;
Chris@59: 
Chris@59:     if (value <= 0) {
Chris@59:         factor = 1.0 - (value / 100.0);
Chris@59:     } else {
Chris@59:         factor = 1.0 / (1.0 + (value / 100.0));
Chris@59:     }
Chris@59: 
Chris@59: //    std::cerr << "value = " << value << " factor = " << factor << std::endl;
Chris@59:     return factor;
Chris@59: }
Chris@59: 
Chris@59: float
Chris@59: PlaySpeedRangeMapper::getFactorForPosition(int position) const
Chris@59: {
Chris@59:     bool slow = false;
Chris@59: 
Chris@59:     if (position < m_minpos) position = m_minpos;
Chris@59:     if (position > m_maxpos) position = m_maxpos;
Chris@59: 
Chris@59:     int half = (m_maxpos + m_minpos) / 2;
Chris@59: 
Chris@59:     if (position < half) {
Chris@59:         slow = true;
Chris@59:         position = half - position;
Chris@59:     } else {
Chris@59:         position = position - half;
Chris@59:     }
Chris@59: 
Chris@59:     // position is between min and half (inclusive)
Chris@59: 
Chris@59:     float factor;
Chris@59: 
Chris@59:     if (position == m_minpos) {
Chris@59:         factor = 1.0;
Chris@59:     } else {
Chris@59:         factor = ((position - m_minpos) * 100.0) / (half - m_minpos);
Chris@59:         factor = 1.0 + (factor * factor) / 1000.f;
Chris@59:     }
Chris@59: 
Chris@59:     if (!slow) factor = 1.0 / factor;
Chris@59: 
Chris@59: //    std::cerr << "position = " << position << " slow = " << slow << " factor = " << factor << std::endl;
Chris@59: 
Chris@59:     return factor;
Chris@59: }
Chris@59: 
Chris@59: QString
Chris@59: PlaySpeedRangeMapper::getUnit() const
Chris@59: {
Chris@59:     return "%";
Chris@59: }