view audioio/AudioCallbackPlayTarget.h @ 4:5865094175ea

* Fix update and play limits for play-selection mode when not looping
* Fix playback in loop mode when no selection -- but the GUI update for
  this is still wrong on the flyback
* Various fixes and improvements to making selections, particularly during
  playback
* Draw selection under non-opaque non-scrollable layers, so as to improve
  cacheing
* Show selection limits as text when drawing selection
* Allow user to find missing audio files when loading session
* Cross-fade selections when in play-selection mode -- mostly.  We don't
  cross-fade on a processing block boundary, and unfortunately with short
  selections the selection boundary is quite likely to coincide with a block
  boundary.

/* -*- c-basic-offset: 4 -*-  vi:set ts=8 sts=4 sw=4: */

/*
    A waveform viewer and audio annotation editor.
    Chris Cannam, Queen Mary University of London, 2005-2006
    
    This is experimental software.  Not for distribution.
*/

#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