xyseriesiodevice.cpp Example File

audio/xyseriesiodevice.cpp
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 #include "xyseriesiodevice.h"

 #include <QtCharts/QXYSeries>

 XYSeriesIODevice::XYSeriesIODevice(QXYSeries *series, QObject *parent) :
     QIODevice(parent),
     m_series(series)
 {
 }

 qint64 XYSeriesIODevice::readData(char *data, qint64 maxSize)
 {
     Q_UNUSED(data)
     Q_UNUSED(maxSize)
     return -1;
 }

 qint64 XYSeriesIODevice::writeData(const char *data, qint64 maxSize)
 {
     static const int resolution = 4;

     if (m_buffer.isEmpty()) {
         m_buffer.reserve(sampleCount);
         for (int i = 0; i < sampleCount; ++i)
             m_buffer.append(QPointF(i, 0));
     }

     int start = 0;
     const int availableSamples = int(maxSize) / resolution;
     if (availableSamples < sampleCount) {
         start = sampleCount - availableSamples;
         for (int s = 0; s < start; ++s)
             m_buffer[s].setY(m_buffer.at(s + availableSamples).y());
     }

     for (int s = start; s < sampleCount; ++s, data += resolution)
         m_buffer[s].setY(qreal(uchar(*data) -128) / qreal(128));

     m_series->replace(m_buffer);
     return (sampleCount - start) * resolution;
 }