Method setReferencePosition

pj_plotting/widget/src/CurveTracker.cpp:228–231

}

void CurveTracker::setReferencePosition(std::optional<QPointF> reference_pos) {
  reference_pos_ = reference_pos;
  redraw();
}

std::optional<QPointF> curvePointAt(const QwtPlotCurve* curve, double x) {
  if (curve == nullptr || curve->dataSize() == 0) {