csndmixer.h

手机操作系统Symbian支持混音功能的声音引擎代码

/*
 * ============================================================================
 *  Name     : CSndMixer.h
 *  Part of  : SoundMixer
 *  Created  : 03/30/2006 by Forum Nokia
 *  Description:
 *     This is the project specification file for SoundMixer.
 *
 *  Version  : 2.0.0
 *  Copyright: Forum Nokia
 * ============================================================================
 */

#ifndef __CSNDMIXER_H__
#define __CSNDMIXER_H__

// INCLUDES
#include <E32Base.h>
#include "TSample.h"
#include "TAudioShared.h"

// CLASS DECLARATION
/**
* CSndMixer is the main class for user to produce sound.
* this class creates second thread where the main mixer resides.
* Messages to the second thread are sent via exceptions.
*
* Usage example:
* CSndMixer* iMixer;
* ..
* iMixer = CSndMixer->NewL();
* // plays sample iSample in channel 0 with frequency 16000Hz
* // and volume 300
* iMixer->Play( iSample, 0, 16000, 300 );
*
*/
class CSndMixer
  : public CBase
  {
  public:
    /// Two-phased constructor
    static CSndMixer* NewL();

    /// Default destructor
    ~CSndMixer();

  private:

    /// Default constructor
    CSndMixer();

    /// Second phase constructor
    void ConstructL();

  public:

    /// Pauses mixer
    void Pause();

    /// Resumes mixer
    void Resume();

    /// Plays a sample with given parameters
    /// @param aSample sample to play
    /// @param aChannel channel 0-15 to play the sample on
    /// @param aVolume volume to play sample with, default is 256
    void Play( const TSample& aSample, TInt aChannel, TInt aFrequency, TInt aVolume = 256 );

    /// Stops sample from playing in given channel
    /// @param aChannel channel to play sample in
    void Stop( TInt aChannel );

    /// Sets the main volume
    /// @param aVolume new main volume
    void SetVolume( TInt aVolume );

    /// returns main volume
    /// @return main volume
    TInt Volume();

  private:

    void SendCmd( TMixerCmd aCmd );

  private:

    TAudioShared  iShared;        // shared data with mixer thread
    RThread       iMixerThread;   // handle to mixer thread
    TSample       iEmptySample;   // empty sample, used to stop channel
    TBool         iPaused;        // paused flag
  };
  
#endif

// End of File