annotate layer/SliceableLayer.h @ 959:2633a1d73e39

Address #1214, layer import produces wrong layer type. We needed a more principled approach to making sure the format gets updated properly and the dialog elements are consistent (basically separating making the dialog elements consistent from subsequently updating the format). This change should provide that, though there may be gotchas still.

/* -*- 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 2007 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 _SLICEABLE_LAYER_H_
#define _SLICEABLE_LAYER_H_

#include "Layer.h"

/**
 * Base class for layers that can be sliced, that is, that contain
 * models appropriate for use in a SliceLayer.
 */

class SliceableLayer : public Layer
{
    Q_OBJECT

public:
    // Get a model that can be sliced, i.e. a
    // DenseThreeDimensionalModel.  This may be the layer's usual
    // model, or it may be a model derived from it (e.g. FFTModel in a
    // spectrogram that was constructed from a DenseTimeValueModel).
    // The SliceableLayer retains ownership of the model, and will
    // emit sliceableModelReplaced if it is about to become invalid.
    virtual const Model *getSliceableModel() const = 0;

signals:
    // Emitted when a model that was obtained through
    // getSliceableModel is about to be deleted.  If replacement is
    // non-NULL, it may be used instead.
    void sliceableModelReplaced(const Model *modelToBeReplaced,
                                const Model *replacement);
};

#endif