void MainWindow::drawChart(QtCharts::QChart *chart, QtCharts::QXYSeries *series, const QModelIndex &index)
{
    QPointF p;
    QVector<QPointF> points;

    double min_x = std::numeric_limits<double>::max();
    double max_x = -std::numeric_limits<double>::max();

    double min_y = std::numeric_limits<double>::max();
    double max_y = -std::numeric_limits<double>::max();

    QList<QVariant> var = index.data(Qt::DisplayRole).toList();
    for (int i = 0; i < var.size(); i++)
    {
        p = var.at(i).toPointF();
        points << p;

        min_x = std::min(min_x, p.x());
        min_y = std::min(min_y, p.y());

        max_x = std::max(max_x, p.x());
        max_y = std::max(max_y, p.y());
    }

    series->replace(points);

    chart->axisX()->setRange(min_x, max_x);
    chart->axisY()->setRange(min_y, max_y);
}