added more checks and fixed another warning

Applications/DataExplorer/DataView/DiagramView/DiagramList.cpp

@@ -304,8 +304,11 @@ void DiagramList::truncateToRange(QDateTime const& start, QDateTime const& end)
     update();
 }
 
-void DiagramList::setList(std::vector< std::pair<QDateTime, float> > coords)
+void DiagramList::setList(std::vector<std::pair<QDateTime, float>> const& coords)
 {
+    if (coords.empty())
+        return;
+
     this->_startDate = coords[0].first;
     _coords.emplace_back(0.0f, coords[0].second);
 
@@ -320,8 +323,11 @@ void DiagramList::setList(std::vector< std::pair<QDateTime, float> > coords)
     update();
 }
 
-void DiagramList::setList(std::vector< std::pair<float, float> > coords)
+void DiagramList::setList(std::vector< std::pair<float, float> > const& coords)
 {
+    if (coords.empty())
+        return;
+
     this->_startDate = QDateTime();
     std::size_t nCoords = coords.size();
     for (std::size_t i = 0; i < nCoords; i++)

Applications/DataExplorer/DataView/DiagramView/DiagramList.h

@@ -124,7 +124,7 @@ public:
      * Sets the list of x/y-coordinates.
      * \param coords List of coordinates.
      */
-    void setList(std::vector< std::pair<float, float> > coords);
+    void setList(std::vector< std::pair<float, float> > const& coords);
 
     /**
      * Sets the list of x/y-coordinates.
@@ -132,7 +132,7 @@ public:
      * days from the first date (which is set as day 0)
      * \param coords List of coordinates.
      */
-    void setList(std::vector< std::pair<QDateTime, float> > coords);
+    void setList(std::vector< std::pair<QDateTime, float> > const& coords);
 
     /// Specifies the unit of the x Axis.
     void setXUnit(QString unit) { _xUnit = unit; }

Applications/DataExplorer/DataView/DiagramView/DiagramPrefsDialog.cpp

@@ -77,7 +77,8 @@ void DiagramPrefsDialog::accept()
         return;
     }
 
-    // data has been loaded
+    // Data has been loaded.
+    // If loading the other lists fails at least nothing terrible will happen.
     if (_list[0]->size() > 0)
     {
         bool window_is_empty(false);

Applications/DataExplorer/DataView/DiagramView/QArrow.cpp

@@ -117,7 +117,7 @@ void QArrow::paint(QPainter* painter, const QStyleOptionGraphicsItem* option, QW
 }
 
 /// Changes orientation of the arrow.
-void QArrow::setAngle(float a)
+void QArrow::setAngle(qreal a)
 {
     _arrowAngle = a;
 }

Applications/DataExplorer/DataView/DiagramView/QArrow.h

@@ -35,7 +35,7 @@ public:
     void paint(QPainter* painter, const QStyleOptionGraphicsItem* option,
                QWidget* widget) override;
     QRectF boundingRect() const override;
-    void setAngle(float a);
+    void setAngle(qreal a);
     void setLength(qreal l);
 
 private: