Qt 5.11 | Qt Charts | Audio Example | xyseriesiodevice.cpp Example File

Qt Charts | Commercial or GPLv3

# xyseriesiodevice.cpp Example File

audio/xyseriesiodevice.cpp

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      ** This file is part of the Qt Charts module of the Qt Toolkit.
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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;
      }