Method getErrorBarLines

src/qt/qcustomplot.cpp:27730–27779

! \internal Calculates the lines that make up the error bar belonging to the data point \a it. The resulting lines are added to \a backbones and \a whiskers. The vectors are not cleared, so calling this method with different \a it but the same \a backbones and \a whiskers allows to accumulate lines for multiple data points. This method assumes that \a it is a valid iterator within the

  instance and within the bounds of the associated data plottable.
*/
void QCPErrorBars::getErrorBarLines(QCPErrorBarsDataContainer::const_iterator it, QVector<QLineF> &backbones, QVector<QLineF> &whiskers) const
{
  if (!mDataPlottable) return;
  
  int index = it-mDataContainer->constBegin();
  QPointF centerPixel = mDataPlottable->interface1D()->dataPixelPosition(index);
  if (qIsNaN(centerPixel.x()) || qIsNaN(centerPixel.y()))
    return;
  QCPAxis *errorAxis = mErrorType == etValueError ? mValueAxis.data() : mKeyAxis.data();
  QCPAxis *orthoAxis = mErrorType == etValueError ? mKeyAxis.data() : mValueAxis.data();
  const double centerErrorAxisPixel = errorAxis->orientation() == Qt::Horizontal ? centerPixel.x() : centerPixel.y();
  const double centerOrthoAxisPixel = orthoAxis->orientation() == Qt::Horizontal ? centerPixel.x() : centerPixel.y();
  const double centerErrorAxisCoord = errorAxis->pixelToCoord(centerErrorAxisPixel); // depending on plottable, this might be different from just mDataPlottable->interface1D()->dataMainKey/Value
  const double symbolGap = mSymbolGap*0.5*errorAxis->pixelOrientation();
  // plus error:
  double errorStart, errorEnd;
  if (!qIsNaN(it->errorPlus))
  {
    errorStart = centerErrorAxisPixel+symbolGap;
    errorEnd = errorAxis->coordToPixel(centerErrorAxisCoord+it->errorPlus);
    if (errorAxis->orientation() == Qt::Vertical)
    {
      if ((errorStart > errorEnd) != errorAxis->rangeReversed())
        backbones.append(QLineF(centerOrthoAxisPixel, errorStart, centerOrthoAxisPixel, errorEnd));
      whiskers.append(QLineF(centerOrthoAxisPixel-mWhiskerWidth*0.5, errorEnd, centerOrthoAxisPixel+mWhiskerWidth*0.5, errorEnd));
    } else
    {
      if ((errorStart < errorEnd) != errorAxis->rangeReversed())
        backbones.append(QLineF(errorStart, centerOrthoAxisPixel, errorEnd, centerOrthoAxisPixel));
      whiskers.append(QLineF(errorEnd, centerOrthoAxisPixel-mWhiskerWidth*0.5, errorEnd, centerOrthoAxisPixel+mWhiskerWidth*0.5));
    }
  }
  // minus error:
  if (!qIsNaN(it->errorMinus))
  {
    errorStart = centerErrorAxisPixel-symbolGap;
    errorEnd = errorAxis->coordToPixel(centerErrorAxisCoord-it->errorMinus);
    if (errorAxis->orientation() == Qt::Vertical)
    {
      if ((errorStart < errorEnd) != errorAxis->rangeReversed())
        backbones.append(QLineF(centerOrthoAxisPixel, errorStart, centerOrthoAxisPixel, errorEnd));
      whiskers.append(QLineF(centerOrthoAxisPixel-mWhiskerWidth*0.5, errorEnd, centerOrthoAxisPixel+mWhiskerWidth*0.5, errorEnd));
    } else
    {
      if ((errorStart > errorEnd) != errorAxis->rangeReversed())
        backbones.append(QLineF(errorStart, centerOrthoAxisPixel, errorEnd, centerOrthoAxisPixel));
      whiskers.append(QLineF(errorEnd, centerOrthoAxisPixel-mWhiskerWidth*0.5, errorEnd, centerOrthoAxisPixel+mWhiskerWidth*0.5));
    }
  }
}

/*! \internal