Method getStackedBaseValue

qcustomplot/qcustomplot.cpp:24270–24295

! \internal This function is called to find at which value to start drawing the base of a bar at \a key, when it is stacked on top of another QCPBars (e.g. with \ref moveAbove). positive and negative bars are separated per stack (positive are stacked above baseValue upwards, negative are stacked below baseValue downwards). This can be indicated with \a positive. So if the bar for w

  bar for which we need the base value is negative, set \a positive to false.
*/
double QCPBars::getStackedBaseValue(double key, bool positive) const
{
  if (mBarBelow)
  {
    double max = 0; // don't initialize with mBaseValue here because only base value of bottom-most bar has meaning in a bar stack
    // find bars of mBarBelow that are approximately at key and find largest one:
    double epsilon = qAbs(key)*(sizeof(key)==4 ? 1e-6 : 1e-14); // should be safe even when changed to use float at some point
    if (key == 0)
      epsilon = (sizeof(key)==4 ? 1e-6 : 1e-14);
    QCPBarsDataContainer::const_iterator it = mBarBelow.data()->mDataContainer->findBegin(key-epsilon);
    QCPBarsDataContainer::const_iterator itEnd = mBarBelow.data()->mDataContainer->findEnd(key+epsilon);
    while (it != itEnd)
    {
      if (it->key > key-epsilon && it->key < key+epsilon)
      {
        if ((positive && it->value > max) ||
            (!positive && it->value < max))
          max = it->value;
      }
      ++it;
    }
    // recurse down the bar-stack to find the total height:
    return max + mBarBelow.data()->getStackedBaseValue(key, positive);
  } else
    return mBaseValue;
}

/*! \internal