Qt QXYSeries and ChartView - modify hovered behavior to trigger within a range

Question

I have a scatter plot represented by a QXYSeries and viewed with a ChartView from Qt Charts 5.7.

I want to hover my mouse over the plot, have "hovered" trigger within a certain distance, rather than only when my cursor is directly on top of a point. Imagine a circle around the mouse, that will trigger hovered whenever any part of the series is within it.

Is there a way to get this behavior?

Answer 1

Eventually, I got this behavior by creating a class that inherits from QChartView and overriding mouseMoveEvent(QMouseEvent* event) thusly:

void ScatterView::mouseMoveEvent(QMouseEvent* event)
{
    if(!this->chart()->axisX() || !this->chart()->axisY())
    {
        return;
    }
    QPointF inPoint;
    QPointF chartPoint;
    inPoint.setX(event->x());
    inPoint.setY(event->y());
    chartPoint = chart()->mapToValue(inPoint);
    handleMouseMoved(chartPoint);
}

void ScatterView::handleMouseMoved(const QPointF &point)
{
    QPointF mousePoint = point;
    qreal distance(0.2); //distance from mouse to point in chart axes
    foreach (QPointF currentPoint, scatterSeries->points()) { 
        qreal currentDistance = qSqrt((currentPoint.x() - mousePoint.x())
                                      * (currentPoint.x() - mousePoint.x())
                                      + (currentPoint.y() - mousePoint.y())
                                      * (currentPoint.y() - mousePoint.y()));
        if (currentDistance < distance) {
            triggerPoint(currentPoint);
        }
    }
}