annotate layer/HorizontalScaleProvider.h @ 1551:e79731086b0f

Fixes to NoteLayer, particularly to calculation of vertical scale when model unit is not Hz. To avoid inconsistency we now behave as if the unit is always Hz from the point of view of the external API and display, converting at the point where we obtain values from the events themselves. Also various fixes to editing.

/* -*- 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 2006-2018 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_HORIZONTAL_SCALE_PROVIDER_H
#define SV_HORIZONTAL_SCALE_PROVIDER_H

class LayerGeometryProvider;

/**
 * Interface to be implemented by objects, such as layers or objects
 * they delegate to, in which the X axis corresponds to frequency. For
 * example, SpectrumLayer.
 */
class HorizontalScaleProvider
{
public:
    virtual double getFrequencyForX(const LayerGeometryProvider *,
                                    double x)
        const = 0;
    
    virtual double getXForFrequency(const LayerGeometryProvider *,
                                    double freq)
        const = 0;
};

#endif