message: Speed up stepifySeries step chart interpolation method
diff: @@ -20,16 +20,26 @@ namespace {
  * @brief stepifySeries
  * Adds additional points to a QLineSeries, effectively transforming it into a step plot to avoid the default point
  * interpolation of a QLineSeries.
  + * We create a new pointsVector, preallocate the known final size and finally exchange the points. This is a lot faster
  + * than individually inseting points into the series, which each will trigger events within the QLineSeries.
  */
  void stepifySeries(QLineSeries& series) {
  if (series.count() == 0)
  return;
  - for (int i = series.count() - 1; i != 0; i--) {
  - QPointF interPoint = series.at(i);
  - interPoint.setY(series.at(i - 1).y());
  - series.insert(i, interPoint);
  + QVector<QPointF> points;
  + points.reserve(series.count() * 2);
  +
  + points << series.at(0); // No stepping is done for the first point
  + for (int i = 1; i < series.count(); i++) {
  + const QPointF& stepFrom = series.at(i - 1);
  + const QPointF& stepTo = series.at(i);
  + QPointF interPoint = stepFrom;
  + interPoint.setX(stepTo.x());
  + points << interPoint << stepTo;
  }
  +
  + series.replace(points);
  }
  /**
  