annotate base/AudioRecordTarget.h @ 1376:d9511f9e04d7 dev/refactor-piper-related

Introduce some POD structs for describing an external server application and the desired libraries to load from it, and disambiguating between empty list request and invalid list request. This allows for overriding PiperVampPluginFactory behaviour for using a PluginScan to populate the list request.

/* -*- 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 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_AUDIO_RECORD_TARGET_H
#define SV_AUDIO_RECORD_TARGET_H

#include "BaseTypes.h"

/**
 * The record target API used by the view manager. See also AudioPlaySource.
 */
class AudioRecordTarget
{
public:
    virtual ~AudioRecordTarget() { }

    /**
     * Return whether recording is currently happening.
     */
    virtual bool isRecording() const = 0;

    /**
     * Return the approximate duration of the audio recording so far.
     */
    virtual sv_frame_t getRecordDuration() const = 0;

    /**
     * Return the current (or thereabouts) input levels in the range
     * 0.0 -> 1.0, for metering purposes. Only valid while recording.
     * The values returned are peak values since the last call to this
     * function was made (i.e. calling this function also resets them).
     */
    virtual bool getInputLevels(float &left, float &right) = 0;
};

#endif