view base/RangeMapper.cpp @ 335:02d2ad95ea52 spectrogram-cache-rejig

* Get storage advice for each cache in an FFT data server.  Allows us to be
  more confident about the actual memory situation and cut over from memory
  to disc part way through an FFT calculation if necessary.  StorageAdviser
  is now a bit too optimistic though (it's too keen to allocate large numbers
  of small blocks in memory).

/* -*- c-basic-offset: 4 indent-tabs-mode: nil -*-  vi:set ts=8 sts=4 sw=4: */

/*
    Sonic Visualiser
    An audio file viewer and annotation editor.
    Centre for Digital Music, Queen Mary, University of London.
    This file copyright 2006 QMUL.
    
    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.  See the file
    COPYING included with this distribution for more information.
*/

#include "RangeMapper.h"

#include <cassert>
#include <cmath>

#include <iostream>

LinearRangeMapper::LinearRangeMapper(int minpos, int maxpos,
				     float minval, float maxval,
                                     QString unit) :
    m_minpos(minpos),
    m_maxpos(maxpos),
    m_minval(minval),
    m_maxval(maxval),
    m_unit(unit)
{
    assert(m_maxval != m_minval);
    assert(m_maxpos != m_minpos);
}

int
LinearRangeMapper::getPositionForValue(float value) const
{
    int position = m_minpos +
        lrintf(((value - m_minval) / (m_maxval - m_minval))
               * (m_maxpos - m_minpos));
    if (position < m_minpos) position = m_minpos;
    if (position > m_maxpos) position = m_maxpos;
//    std::cerr << "LinearRangeMapper::getPositionForValue: " << value << " -> "
//              << position << " (minpos " << m_minpos << ", maxpos " << m_maxpos << ", minval " << m_minval << ", maxval " << m_maxval << ")" << std::endl;
    return position;
}

float
LinearRangeMapper::getValueForPosition(int position) const
{
    float value = m_minval +
        ((float(position - m_minpos) / float(m_maxpos - m_minpos))
         * (m_maxval - m_minval));
    if (value < m_minval) value = m_minval;
    if (value > m_maxval) value = m_maxval;
//    std::cerr << "LinearRangeMapper::getValueForPosition: " << position << " -> "
//              << value << " (minpos " << m_minpos << ", maxpos " << m_maxpos << ", minval " << m_minval << ", maxval " << m_maxval << ")" << std::endl;
    return value;
}

LogRangeMapper::LogRangeMapper(int minpos, int maxpos,
                               float ratio, float minlog,
                               QString unit) :
    m_minpos(minpos),
    m_maxpos(maxpos),
    m_ratio(ratio),
    m_minlog(minlog),
    m_unit(unit)
{
    assert(m_maxpos != m_minpos);

    m_maxlog = (m_maxpos - m_minpos) / m_ratio + m_minlog;
}

int
LogRangeMapper::getPositionForValue(float value) const
{
    float mapped = m_ratio * log10(value);
    int position = lrintf(((mapped - m_minlog) / (m_maxlog - m_minlog))
                          * (m_maxpos - m_minpos));
    if (position < m_minpos) position = m_minpos;
    if (position > m_maxpos) position = m_maxpos;
//    std::cerr << "LogRangeMapper::getPositionForValue: " << value << " -> "
//              << position << " (minpos " << m_minpos << ", maxpos " << m_maxpos << ", ratio " << m_ratio << ", minlog " << m_minlog << ")" << std::endl;
    return position;
}

float
LogRangeMapper::getValueForPosition(int position) const
{
    float value = powf(10, (position - m_minpos) / m_ratio + m_minlog);
//    std::cerr << "LogRangeMapper::getValueForPosition: " << position << " -> "
//              << value << " (minpos " << m_minpos << ", maxpos " << m_maxpos << ", ratio " << m_ratio << ", minlog " << m_minlog << ")" << std::endl;
    return value;
}