QQuickPaintedItem and QwtPlotPicker: how to force them to work together - c++

Question

There's a class inherited QQuickPaintedItem and included QwtPlot (in order to use it in QML):
class QmlQwtPlot : public QQuickPaintedItem
{
Q_OBJECT
public:
QmlQwtPlot(QQuickItem* parent = 0);
~QmlQwtPlot();
void paint(QPainter *painter) override;
void mousePressEvent(QMouseEvent *event) override;
void mouseMoveEvent(QMouseEvent* event) override;
void mouseReleaseEvent(QMouseEvent* event) override;
void wheelEvent(QWheelEvent *event) override;
private:
QwtPlot* qwtPlot;
QwtPlotPanner* panner;
bool isDragging;
QPoint previousPosition;
QwtPlotPicker* picker;
};
For example, panning a plot was implemented by using mouse events handling and the QwtPlotPanner's signal :
void QmlQwtPlot::mouseMoveEvent(QMouseEvent* event) {
if (isDragging) { // if the mouse button has been pressed
QPoint currentPosition = event->pos();
QPoint diff = currentPosition - previousPosition;
emit panner->panned(diff.x(),diff.y());
previousPosition = event->pos();
update();
}
}
QwtPlotPicker is a Qwt library class providing selections on a plot canvas. QwtPlotPicker works well (a cursor with x,y coordinates of point and cross-line moving with cursor are appeared) with QWidget, but it doesn't work with QQuickPaintedItem because of different principles of work.
/* QWidget's child constructor (the same is in QQuickPaintedItem's one) */
PlottingWidget::PlottingWidget(QWidget *parent)
: QWidget(parent)
{
// ...
d_picker = new QwtPlotPicker(
QwtPlot::xBottom, QwtPlot::yLeft,
QwtPlotPicker::CrossRubberBand,
QwtPicker::AlwaysOn,
plot->canvas()
);
d_picker->setRubberBandPen( QColor( Qt::red ) );
d_picker->setTrackerPen( QColor( Qt::black ) );
d_picker->setStateMachine( new QwtPickerTrackerMachine() );
// ...
}
How to force QwtPlotPicker work with QQuickPaintedItem?