Method CalcMetersDiff

libs/drape_frontend/gui/ruler_helper.cpp:184–233

}

double RulerHelper::CalcMetersDiff(double value)
{
  UnitValue const * arrU = g_arrMeters;
  int count = ARRAY_SIZE(g_arrMeters);

  auto conversionFn = &Identity;

  using namespace measurement_utils;
  if (GetMeasurementUnits() == Units::Imperial)
  {
    arrU = g_arrFeets;
    count = ARRAY_SIZE(g_arrFeets);
    conversionFn = &MetersToFeet;
  }

  int prevUnitRange = m_rangeIndex;
  double result = 0.0;
  double v = conversionFn(value);
  if (arrU[0].m_i > v)
  {
    m_rangeIndex = kMinUnitValue;
    // TODO: "< X" ruler text seems to be never used.
    m_rulerText = std::string("< ") + arrU[0].m_s;
    result = kMinMetersWidth - 1.0;
  }
  else if (arrU[count - 1].m_i <= v)
  {
    m_rangeIndex = kMaxUnitValue;
    m_rulerText = std::string("> ") + arrU[count - 1].m_s;
    result = kMaxMetersWidth + 1.0;
  }
  else
  {
    for (int i = 0; i < count; ++i)
    {
      if (arrU[i].m_i > v)
      {
        m_rangeIndex = i;
        result = arrU[i].m_i / conversionFn(1.0);
        m_rulerText = arrU[i].m_s;
        break;
      }
    }
  }

  if (m_rangeIndex != prevUnitRange)
    SetTextDirty();

  return result;
}

void RulerHelper::SetTextDirty()
{