Qt 4.8: voicegenerator.h Example File (demos/mobile/guitartuner/src/voicegenerator.h)

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# voicegenerator.h Example File

demos/mobile/guitartuner/src/voicegenerator.h

     /****************************************************************************
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     ** Copyright (C) 2015 The Qt Company Ltd.
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     ** This file is part of the QtDeclarative module of the Qt Toolkit.
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     #ifndef VOICEGENERATOR_H
     #define VOICEGENERATOR_H

     #include <QIODevice>
     #include <QByteArray>
     #include <QAudioFormat>
     #include <QtCore/qmath.h>
     #include <QtCore/qendian.h>
     #include <QDebug>

     #include "constants.h"

     class VoiceGenerator : public QIODevice
     {
         Q_OBJECT
     public:
         VoiceGenerator(const QAudioFormat &format, qreal frequency, qreal amplitude, QObject *parent = 0);
         ~VoiceGenerator();
         void setFrequency(qreal frequency);
         qint64 readData(char *data, qint64 maxlen);
         qint64 writeData(const char *data, qint64 maxlen);
         qint64 bytesAvailable() const;
         qreal frequency();
     signals:

     public slots:
         void setAmplitude(qreal amplitude);
         void start();
         void stop();

     private:
         void setValue(uchar *ptr, qreal realValue);
         void refreshData();
         const QAudioFormat m_format;
         // buffer to store the data
         QByteArray m_buffer;
         // current position in buffer
         qint64 m_position;
         // max position depends on the sample rate of format and the frequency of voice
         qint64 m_max_position;
         qreal m_amplitude;
         qreal m_frequency;
     };

     #endif // VOICEGENERATOR_H