Qt 5.7 | Qt Charts | Audio Example | xyseriesiodevice.cpp Example File

Qt 5.7.1 Reference Documentation

# xyseriesiodevice.cpp Example File

audio/xyseriesiodevice.cpp

      /****************************************************************************
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      ** Copyright (C) 2016 The Qt Company Ltd.
      ** Contact: https://www.qt.io/licensing/
      **
      ** 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)
      {
          qint64 range = 2000;
          QVector<QPointF> oldPoints = m_series->pointsVector();
          QVector<QPointF> points;
          int resolution = 4;

          if (oldPoints.count() < range) {
              points = m_series->pointsVector();
          } else {
              for (int i = maxSize/resolution; i < oldPoints.count(); i++)
                  points.append(QPointF(i - maxSize/resolution, oldPoints.at(i).y()));
          }

          qint64 size = points.count();
          for (int k = 0; k < maxSize/resolution; k++)
              points.append(QPointF(k + size, ((quint8)data[resolution * k] - 128)/128.0));

          m_series->replace(points);
          return maxSize;
      }