view data/model/RangeSummarisableTimeValueModel.h @ 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 2006-2007 Chris Cannam and 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.
*/

#ifndef _RANGE_SUMMARISABLE_TIME_VALUE_MODEL_H_
#define _RANGE_SUMMARISABLE_TIME_VALUE_MODEL_H_

#include <QObject>

#include "DenseTimeValueModel.h"
#include "base/ZoomConstraint.h"

#include <stdint.h>

/**
 * Base class for models containing dense two-dimensional data (value
 * against time) that may be meaningfully represented in a zoomed view
 * using min/max range summaries.  Audio waveform data is an obvious
 * example: think "peaks and minima" for "ranges".
 */

class RangeSummarisableTimeValueModel : public DenseTimeValueModel
{
    Q_OBJECT

public:
    RangeSummarisableTimeValueModel() { }

    class Range
    {
    public:
        Range() : 
            m_new(true), m_min(0.f), m_max(0.f), m_absmean(0.f) { }
        Range(const Range &r) : 
            m_new(true), m_min(r.m_min), m_max(r.m_max), m_absmean(r.m_absmean) { }
        Range(float min, float max, float absmean) :
            m_new(true), m_min(min), m_max(max), m_absmean(absmean) { }

        float min() const { return m_min; }
        float max() const { return m_max; }
        float absmean() const { return m_absmean; }

        void setMin(float min) { m_min = min; m_new = false; }
        void setMax(float max) { m_max = max; m_new = false; }
        void setAbsmean(float absmean) { m_absmean = absmean; }

        void sample(float s) {
            if (m_new) {
                m_min = s;
                m_max = s;
                m_new = false;
            } else {
                if (s < m_min) m_min = s;
                if (s > m_max) m_max = s;
            }
        }
        
    private:
        bool m_new;
        float m_min;
        float m_max;
        float m_absmean;
    };

    typedef std::vector<Range> RangeBlock;

    /**
     * Return ranges from the given start frame, corresponding to the
     * given number of underlying sample frames, summarised at the
     * given block size.  duration / blockSize ranges should ideally
     * be returned.
     *
     * If the given block size is not supported by this model
     * (according to its zoom constraint), also modify the blockSize
     * parameter so as to return the block size that was actually
     * obtained.
     */
    virtual void getSummaries(int channel, sv_frame_t start, sv_frame_t count,
                              RangeBlock &ranges,
                              int &blockSize) const = 0;

    /**
     * Return the range from the given start frame, corresponding to
     * the given number of underlying sample frames, summarised at a
     * block size equal to the distance between start and end frames.
     */
    virtual Range getSummary(int channel, sv_frame_t start, sv_frame_t count) const = 0;

    virtual int getSummaryBlockSize(int desired) const = 0;

    QString getTypeName() const { return tr("Range-Summarisable Time-Value"); }
};

#endif