view data/model/RangeSummarisableTimeValueModel.h @ 1455:ec9e65fcf749

The use of the begin/end pairs here just seems to cause too many rows to be deleted (from the visual representation, not the underlying model). Things apparently work better if we just modify the underlying model and let the change signals percolate back up again. To that end, update the change handlers so as to cover their proper ranges with dataChanged signals.

/* -*- 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 SV_RANGE_SUMMARISABLE_TIME_VALUE_MODEL_H
#define SV_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