Show Number of Revolutions for Detector Position

In the real experiment and its manual, the detector position is mainly
measured in revolutions of the axis, one revolution moves the detector
by 2 mm.

To ease the understanding of the manual, the revolution number is added
to the GUI.

src/clientgui.cpp

@@ -187,7 +187,7 @@ QString ClientGui::getBeamholeStateString(const ExperimentState::BeamHoleState s
 void ClientGui::displayExperimentState()
 {
     _ui.lblPressureValue->setText(QStringLiteral("%1 hPa\n%2 Torr").arg(_state.pressure).arg(_state.convertHectoPascalToTorr(_state.pressure)));
-    _ui.lblTargetPosition->setText(QStringLiteral("%1 mm from detector").arg(_state.targetPosition));
+    _ui.lblTargetPosition->setText(tr("%1 mm from detector (%L2 revolutions)").arg(_state.targetPosition).arg((_state.targetPosition - PositionZeroRevolutions) / TargetMovementMillimeterPerRevolution));
     _ui.pbValveStatus->setValue(_state.vacuumValve);
     _ui.pbAdcThreshold->setValue(_state.adcThreshold);
 

src/clientgui.h

@@ -66,6 +66,9 @@ public:
     ClientGui& operator=(ClientGui&& other) = delete;
 
 private:
+    static const constexpr double PositionZeroRevolutions = 14;
+    static const constexpr double TargetMovementMillimeterPerRevolution = 2;
+
     const QString _name;
     const QString _token;
     std::unique_ptr<QWebSocket> _socket;