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29
30#include "xyseriesiodevice.h"
31
32#include <QtCharts/QXYSeries>
33
34XYSeriesIODevice::XYSeriesIODevice(QXYSeries *series, QObject *parent) :
35 QIODevice(parent),
36 m_series(series)
37{
38}
39
40qint64 XYSeriesIODevice::readData(char *data, qint64 maxSize)
41{
42 Q_UNUSED(data)
43 Q_UNUSED(maxSize)
44 return -1;
45}
46
47qint64 XYSeriesIODevice::writeData(const char *data, qint64 maxSize)
48{
49 static const int resolution = 4;
50
51 if (m_buffer.isEmpty()) {
52 m_buffer.reserve(asize: sampleCount);
53 for (int i = 0; i < sampleCount; ++i)
54 m_buffer.append(t: QPointF(i, 0));
55 }
56
57 int start = 0;
58 const int availableSamples = int(maxSize) / resolution;
59 if (availableSamples < sampleCount) {
60 start = sampleCount - availableSamples;
61 for (int s = 0; s < start; ++s)
62 m_buffer[s].setY(m_buffer.at(i: s + availableSamples).y());
63 }
64
65 for (int s = start; s < sampleCount; ++s, data += resolution)
66 m_buffer[s].setY(qreal(uchar(*data) -128) / qreal(128));
67
68 m_series->replace(points: m_buffer);
69 return (sampleCount - start) * resolution;
70}
71

source code of qtcharts/examples/charts/audio/xyseriesiodevice.cpp