Qt QChart背景未更新

Question

我正在使用Qt5.9.6，并且在更改QChart轴范围时不会更新背景。选择其他应用程序作为活动背景后，背景就会立即更新。

更改范围后

有什么主意吗？谢谢

---

我试图为我的应用程序创建一个具有代表性的示例，但是该示例（不幸的是）有效。

#include <QtCharts/QChartView>
#include <QtCharts/QLineSeries>
#include <QtCharts/QScatterSeries>
#include <QtCharts/QChart>
#include <QtCharts/QValueAxis>
#include <QDebug>
#include <qslider>
#include <QLayout>
#include <qwidget>
#include <QtMath>
#include <QApplication>

QT_CHARTS_USE_NAMESPACE

int main(int argc, char *argv[])
{
    QApplication         a {argc, argv};

    struct {
        const double nbr_of_per {5.5};
        // number of samples
        const int    nos        {(int)(nbr_of_per*200*M_PI)};
    } sine_params;

    const int      sld_max {sine_params.nos-1};
    const double       div {100.0};
    QSlider        *   sld {new QSlider{Qt::Horizontal}};
    QChartView     *  view {new QtCharts::QChartView{}};
    QChart         * chart {new QtCharts::QChart{}};
    QLineSeries       sine {};
    QScatterSeries   point {};

    sld->setRange(0, sld_max);
    chart->addSeries(&sine);
    chart->addSeries(&point);

//    for(auto e: chart->series())
//        e->setUseOpenGL(true);

    for(double i{}; i< sine_params.nos;i++)
        sine.append(QPointF{i/div, sin(i/div)});

    point.append(QPointF{});
    point.setMarkerSize(20);

    chart->legend()->hide();

    QValueAxis x_ax;
    x_ax.setRange(0, sine.pointsVector().last().x());
    x_ax.setTickCount(5);
    x_ax.setLabelFormat(QString{"%."+QString::number((int)log10(div))+"f"});
    chart->setAxisX(&x_ax, &sine);
    chart->setAxisX(&x_ax, &point);

    QValueAxis y_ax;
    y_ax.setRange(-1, 1);
    y_ax.setTickCount(5);
    y_ax.setLabelFormat("%.3f");
    chart->setAxisY(&y_ax, &sine);
    chart->setAxisY(&y_ax, &point);

    QFont font{chart->axisX()->labelsFont()};
    font.setPixelSize(20);
    chart->axisX()->setLabelsFont(font);
    chart->axisY()->setLabelsFont(font);

    view->setChart(chart);
    view->setRenderHint(QPainter::Antialiasing);

    QVBoxLayout * vl{new QVBoxLayout};
    vl->addWidget(view);
    vl->addWidget(sld);

    QWidget w;
    w.setLayout(vl);
    w.show();

    QObject::connect(sld, &QSlider::valueChanged,
        [=,&sine,&point](int val){
            QPointF p{val/div, sine.at(val).y()};
            point.clear();
            point.append(p);
            chart->axisX()->setRange(p.x()-(100/div), p.x()+(100/div));
            chart->axisY()->setRange(p.y()-(.1), p.y()+.1);
            // in my misbehaving application i have to use update() and only
            // then I do not get 'leftovers' after changing axis ranges
            // view->scene()->update(view->rect());
        }
    );

    return a.exec();
}

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