view base/RangeMapper.cpp @ 1196:c7b9c902642f spectrogram-minor-refactor

Fix threshold in spectrogram -- it wasn't working in the last release.
There is a new protocol for this. Formerly the threshold parameter had a
range from -50dB to 0 with the default at -50, and -50 treated internally
as "no threshold". However, there was a hardcoded, hidden internal threshold
for spectrogram colour mapping at -80dB with anything below this being rounded
to zero. Now the threshold parameter has range -81 to -1 with the default
at -80, -81 is treated internally as "no threshold", and there is no hidden
internal threshold. So the default behaviour is the same as before, an
effective -80dB threshold, but it is now possible to change this in both
directions. Sessions reloaded from prior versions may look slightly different
because, if the session says there should be no threshold, there will now
actually be no threshold instead of having the hidden internal one.

Still need to do something in the UI to make it apparent that the -81dB
setting removes the threshold entirely. This is at least no worse than the
previous, also obscured, magic -50dB setting.

/* -*- 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 "system/System.h"

#include <cassert>
#include <cmath>

#include <iostream>

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

int
LinearRangeMapper::getPositionForValue(double value) const
{
    int position = getPositionForValueUnclamped(value);
    if (position < m_minpos) position = m_minpos;
    if (position > m_maxpos) position = m_maxpos;
    return position;
}

int
LinearRangeMapper::getPositionForValueUnclamped(double value) const
{
    int position = m_minpos +
        int(lrint(((value - m_minval) / (m_maxval - m_minval))
                  * (m_maxpos - m_minpos)));
    if (m_inverted) return m_maxpos - (position - m_minpos);
    else return position;
}

double
LinearRangeMapper::getValueForPosition(int position) const
{
    if (position < m_minpos) position = m_minpos;
    if (position > m_maxpos) position = m_maxpos;
    double value = getValueForPositionUnclamped(position);
    return value;
}

double
LinearRangeMapper::getValueForPositionUnclamped(int position) const
{
    if (m_inverted) position = m_maxpos - (position - m_minpos);
    double value = m_minval +
        ((double(position - m_minpos) / double(m_maxpos - m_minpos))
         * (m_maxval - m_minval));
    cerr << "getValueForPositionUnclamped(" << position << "): minval " << m_minval << ", maxval " << m_maxval << ", value " << value << endl;
    return value;
}

LogRangeMapper::LogRangeMapper(int minpos, int maxpos,
                               double minval, double maxval,
                               QString unit, bool inverted) :
    m_minpos(minpos),
    m_maxpos(maxpos),
    m_unit(unit),
    m_inverted(inverted)
{
    convertMinMax(minpos, maxpos, minval, maxval, m_minlog, m_ratio);

//    cerr << "LogRangeMapper: minpos " << minpos << ", maxpos "
//              << maxpos << ", minval " << minval << ", maxval "
//              << maxval << ", minlog " << m_minlog << ", ratio " << m_ratio
//              << ", unit " << unit << endl;

    assert(m_maxpos != m_minpos);

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

//    cerr << "LogRangeMapper: maxlog = " << m_maxlog << endl;
}

void
LogRangeMapper::convertMinMax(int minpos, int maxpos,
                              double minval, double maxval,
                              double &minlog, double &ratio)
{
    static double thresh = powf(10, -10);
    if (minval < thresh) minval = thresh;
    minlog = log10(minval);
    ratio = (maxpos - minpos) / (log10(maxval) - minlog);
}

void
LogRangeMapper::convertRatioMinLog(double ratio, double minlog,
                                   int minpos, int maxpos,
                                   double &minval, double &maxval)
{
    minval = pow(10, minlog);
    maxval = pow(10, (maxpos - minpos) / ratio + minlog);
}

int
LogRangeMapper::getPositionForValue(double value) const
{
    int position = getPositionForValueUnclamped(value);
    if (position < m_minpos) position = m_minpos;
    if (position > m_maxpos) position = m_maxpos;
    return position;
}

int
LogRangeMapper::getPositionForValueUnclamped(double value) const
{
    static double thresh = pow(10, -10);
    if (value < thresh) value = thresh;
    int position = int(lrint((log10(value) - m_minlog) * m_ratio)) + m_minpos;
    if (m_inverted) return m_maxpos - (position - m_minpos);
    else return position;
}

double
LogRangeMapper::getValueForPosition(int position) const
{
    if (position < m_minpos) position = m_minpos;
    if (position > m_maxpos) position = m_maxpos;
    double value = getValueForPositionUnclamped(position);
    return value;
}

double
LogRangeMapper::getValueForPositionUnclamped(int position) const
{
    if (m_inverted) position = m_maxpos - (position - m_minpos);
    double value = pow(10, (position - m_minpos) / m_ratio + m_minlog);
    return value;
}

InterpolatingRangeMapper::InterpolatingRangeMapper(CoordMap pointMappings,
                                                   QString unit) :
    m_mappings(pointMappings),
    m_unit(unit)
{
    for (CoordMap::const_iterator i = m_mappings.begin(); 
         i != m_mappings.end(); ++i) {
        m_reverse[i->second] = i->first;
    }
}

int
InterpolatingRangeMapper::getPositionForValue(double value) const
{
    int pos = getPositionForValueUnclamped(value);
    CoordMap::const_iterator i = m_mappings.begin();
    if (pos < i->second) pos = i->second;
    i = m_mappings.end(); --i;
    if (pos > i->second) pos = i->second;
    return pos;
}

int
InterpolatingRangeMapper::getPositionForValueUnclamped(double value) const
{
    double p = interpolate(&m_mappings, value);
    return int(lrint(p));
}

double
InterpolatingRangeMapper::getValueForPosition(int position) const
{
    double val = getValueForPositionUnclamped(position);
    CoordMap::const_iterator i = m_mappings.begin();
    if (val < i->first) val = i->first;
    i = m_mappings.end(); --i;
    if (val > i->first) val = i->first;
    return val;
}

double
InterpolatingRangeMapper::getValueForPositionUnclamped(int position) const
{
    return interpolate(&m_reverse, position);
}

template <typename T>
double
InterpolatingRangeMapper::interpolate(T *mapping, double value) const
{
    // lower_bound: first element which does not compare less than value
    typename T::const_iterator i =
        mapping->lower_bound(typename T::key_type(value));

    if (i == mapping->begin()) {
        // value is less than or equal to first element, so use the
        // gradient from first to second and extend it
        ++i;
    }

    if (i == mapping->end()) {
        // value is off the end, so use the gradient from penultimate
        // to ultimate and extend it
        --i;
    }

    typename T::const_iterator j = i;
    --j;

    double gradient = double(i->second - j->second) / double(i->first - j->first);

    return j->second + (value - j->first) * gradient;
}

AutoRangeMapper::AutoRangeMapper(CoordMap pointMappings,
                                 QString unit) :
    m_mappings(pointMappings),
    m_unit(unit)
{
    m_type = chooseMappingTypeFor(m_mappings);

    CoordMap::const_iterator first = m_mappings.begin();
    CoordMap::const_iterator last = m_mappings.end();
    --last;

    switch (m_type) {
    case StraightLine:
        m_mapper = new LinearRangeMapper(first->second, last->second,
                                         first->first, last->first,
                                         unit, false);
        break;
    case Logarithmic:
        m_mapper = new LogRangeMapper(first->second, last->second,
                                      first->first, last->first,
                                      unit, false);
        break;
    case Interpolating:
        m_mapper = new InterpolatingRangeMapper(m_mappings, unit);
        break;
    }
}

AutoRangeMapper::~AutoRangeMapper()
{
    delete m_mapper;
}

AutoRangeMapper::MappingType
AutoRangeMapper::chooseMappingTypeFor(const CoordMap &mappings)
{
    // how do we work out whether a linear/log mapping is "close enough"?

    CoordMap::const_iterator first = mappings.begin();
    CoordMap::const_iterator last = mappings.end();
    --last;

    LinearRangeMapper linm(first->second, last->second,
                           first->first, last->first,
                           "", false);

    bool inadequate = false;

    for (CoordMap::const_iterator i = mappings.begin();
         i != mappings.end(); ++i) {
        int candidate = linm.getPositionForValue(i->first);
        int diff = candidate - i->second;
        if (diff < 0) diff = -diff;
        if (diff > 1) {
//            cerr << "AutoRangeMapper::chooseMappingTypeFor: diff = " << diff
//                 << ", straight-line mapping inadequate" << endl;
            inadequate = true;
            break;
        }
    }

    if (!inadequate) {
        return StraightLine;
    }

    LogRangeMapper logm(first->second, last->second,
                        first->first, last->first,
                        "", false);

    inadequate = false;

    for (CoordMap::const_iterator i = mappings.begin();
         i != mappings.end(); ++i) {
        int candidate = logm.getPositionForValue(i->first);
        int diff = candidate - i->second;
        if (diff < 0) diff = -diff;
        if (diff > 1) {
//            cerr << "AutoRangeMapper::chooseMappingTypeFor: diff = " << diff
//                 << ", log mapping inadequate" << endl;
            inadequate = true;
            break;
        }
    }

    if (!inadequate) {
        return Logarithmic;
    }

    return Interpolating;
}

int
AutoRangeMapper::getPositionForValue(double value) const
{
    return m_mapper->getPositionForValue(value);
}

double
AutoRangeMapper::getValueForPosition(int position) const
{
    return m_mapper->getValueForPosition(position);
}

int
AutoRangeMapper::getPositionForValueUnclamped(double value) const
{
    return m_mapper->getPositionForValueUnclamped(value);
}

double
AutoRangeMapper::getValueForPositionUnclamped(int position) const
{
    return m_mapper->getValueForPositionUnclamped(position);
}