xyseriesiodevice.cpp 范例文件

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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;
}