xyseriesiodevice.cpp Example File
audio/xyseriesiodevice.cpp
#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;
}