view audioio/AudioCallbackPlayTarget.h @ 88:51be0daa1386

Several changes related to referring to remote URLs for sessions and files:
* Pull file dialog wrapper functions out from MainWindow into FileFinder
* If a file referred to in a session is not found at its expected location,
  try a few other alternatives (same location as the session file or same
  location as the last audio file) before asking the user to locate it
* Allow user to give a URL when locating an audio file, not just locate on
  the filesystem
* Make wave file models remember the "original" location (e.g. URL) of
  the audio file, not just the actual location from which the data was
  loaded (e.g. local copy of that URL) -- when saving a session, use the
  original location so as not to refer to a temporary file
* Clean up incompletely-downloaded local copies of files

/* -*- 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 Chris Cannam.
    
    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 _AUDIO_CALLBACK_PLAY_TARGET_H_
#define _AUDIO_CALLBACK_PLAY_TARGET_H_

#include <QObject>

class AudioCallbackPlaySource;

class AudioCallbackPlayTarget : public QObject
{
    Q_OBJECT

public:
    AudioCallbackPlayTarget(AudioCallbackPlaySource *source);
    virtual ~AudioCallbackPlayTarget();

    virtual bool isOK() const = 0;

    float getOutputGain() const {
	return m_outputGain;
    }

public slots:
    /**
     * Set the playback gain (0.0 = silence, 1.0 = levels unmodified)
     */
    virtual void setOutputGain(float gain);

    /**
     * The main source model (providing the playback sample rate) has
     * been changed.  The target should query the source's sample
     * rate, set its output sample rate accordingly, and call back on
     * the source's setTargetSampleRate to indicate what sample rate
     * it succeeded in setting at the output.  If this differs from
     * the model rate, the source will resample.
     */
    virtual void sourceModelReplaced() = 0;

protected:
    AudioCallbackPlaySource *m_source;
    float m_outputGain;
};

#endif