xyseriesiodevice.cpp Example File | Qt Charts 5.12.9

- Qt 5.12
- Qt Charts
- Audio Example
- xyseriesiodevice.cpp Example File
- Qt Charts | Commercial or GPLv3

# xyseriesiodevice.cpp Example File

audio/xyseriesiodevice.cpp

     /****************************************************************************
     **
     ** 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)
     {
         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;
     }