view data/model/RangeSummarisableTimeValueModel.h @ 410:9c7ebf2cd956

* Halve space requirements for range (waveform peak) caches

/* -*- 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"

/**
 * 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() { }

#define RANGE_USE_SHORT 1
#ifdef RANGE_USE_SHORT
    class Range
    {
    public:
        Range() : 
            m_min(0), m_max(0), m_absmean(0) { }
        Range(const Range &r) : 
            m_min(r.m_min), m_max(r.m_max), m_absmean(r.m_absmean) { }
        Range(float min, float max, float absmean)
        { setMin(min); setMax(max); setAbsmean(absmean); }
        
        float min() const { return i2f(m_min); }
        float max() const { return i2f(m_max); }
        float absmean() const { return i2f(m_absmean); }

        void setMin(float min) { m_min = f2i(min); }
        void setMax(float max) { m_max = f2i(max); }
        void setAbsmean(float absmean) { m_absmean = f2i(absmean); }

    private:
        static inline int16_t f2i(float f) {
            if (f > 1.f) f = 1.f;
            if (f < -1.f) f = -1.f;
            return int16_t(f * 32767.f);
        }
        static inline float i2f(int16_t i) {
            return float(i) / 32767.f;
        }

        int16_t m_min;
        int16_t m_max;
        int16_t m_absmean;
    };
#else
    class Range
    {
    public:
        Range() : 
            m_min(0.f), m_max(0.f), m_absmean(0.f) { }
        Range(const Range &r) : 
            m_min(r.m_min), m_max(r.m_max), m_absmean(r.m_absmean) { }
        Range(float min, float max, float absmean) :
            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; }
        void setMax(float max) { m_max = max; }
        void setAbsmean(float absmean) { m_absmean = absmean; }

    private:
        float m_min;
        float m_max;
        float m_absmean;
    };
#endif

    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(size_t channel, size_t start, size_t count,
                              RangeBlock &ranges,
                              size_t &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(size_t channel, size_t start, size_t count) const = 0;

    virtual size_t getSummaryBlockSize(size_t desired) const = 0;

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

#endif