Refactoring some in-and-out functions in MantidWidgets

re #15286

Framework/DataObjects/src/MDHistoWorkspace.cpp

@@ -609,7 +609,7 @@ MDHistoWorkspace::getLineData(const Mantid::Kernel::VMD &start,
     line.x.push_back(length);
     line.y.push_back(std::numeric_limits<signal_t>::quiet_NaN());
     line.e.push_back(std::numeric_limits<signal_t>::quiet_NaN());
-    return;
+    return line;
   } else {
     // Get the first point
     std::set<coord_t>::iterator it;

MantidQt/MantidWidgets/inc/MantidQtMantidWidgets/InstrumentView/Shape2DCollection.h

@@ -73,7 +73,7 @@ namespace MantidQt
 										// is a point in real space masked by any of the shapes
 			bool isMasked(double x, double y)const;
 			// collect all screen pixels that are masked by the shapes
-			void getMaskedPixels(QList<QPoint>& pixels)const;
+			QList<QPoint> getMaskedPixels()const;
 
 			// set the bounding rect of the current shape such that its real rect is given by the argument
 			void setCurrentBoundingRectReal(const QRectF& rect);

MantidQt/MantidWidgets/inc/MantidQtMantidWidgets/RenameParDialog.h

@@ -23,7 +23,7 @@ namespace MantidQt
       RenameParDialog(const std::vector<std::string>& old_params,
         const std::vector<std::string>& new_params,
         QWidget *parent=NULL);
-      void setOutput(std::vector<std::string>& out)const;
+      std::vector<std::string> setOutput() const;
     protected slots:
       void uniqueIndexedNames(bool);
       void doNotRename(bool);

MantidQt/MantidWidgets/src/InstrumentView/Projection3D.cpp

@@ -273,8 +273,7 @@ namespace MantidQt
 			m_instrActor->cacheDetPos();
 
 			// find the layer of visible detectors
-			QList<QPoint> pixels;
-			m_maskShapes.getMaskedPixels(pixels);
+			QList<QPoint> pixels = m_maskShapes.getMaskedPixels();
 			double zmin = 1.0;
 			double zmax = 0.0;
 			QSet<int> ids;

MantidQt/MantidWidgets/src/InstrumentView/Shape2DCollection.cpp

@@ -702,9 +702,8 @@ namespace MantidQt
 			return false;
 		}
 
-		void Shape2DCollection::getMaskedPixels(QList<QPoint>& pixels)const
-		{
-			pixels.clear();
+		QList<QPoint> Shape2DCollection::getMaskedPixels() const {
+			QList<QPoint> pixels;
 			QTransform inv = m_transform.inverted();
 			for (int i = m_viewport.left(); i <= m_viewport.right(); ++i)
 			{
@@ -721,6 +720,7 @@ namespace MantidQt
 					}
 				}
 			}
+      return pixels;
 		}
 
 		/**

MantidQt/MantidWidgets/src/RenameParDialog.cpp

@@ -96,16 +96,17 @@ QString RenameParDialog::makeUniqueIndexedName(const QString& name)
 
 /**
  * Output the new names to a vector 
- * @param out :: Reference to a vector for output
+ * @returns :: new names in a vector
  */
-void RenameParDialog::setOutput(std::vector<std::string>& out)const
+std::vector<std::string> RenameParDialog::setOutput() const
 {
-  out.clear();
+  std::vector<std::string> out;
   QAbstractItemModel* model = m_uiForm.tableWidget->model();
   for(int row=0;row< m_uiForm.tableWidget->rowCount(); ++row)
   {
     out.push_back(model->data(model->index(row,1)).toString().toStdString());
   }
+  return out;
 }
 
 void RenameParDialog::uniqueIndexedNames(bool ok)

MantidQt/MantidWidgets/src/UserFunctionDialog.cpp

@@ -244,8 +244,7 @@ void UserFunctionDialog::checkParameters(QString& expr)
     RenameParDialog dlg(all,common);
     if (dlg.exec() == QDialog::Accepted)
     {
-      std::vector<std::string> vars_new;
-      dlg.setOutput(vars_new);
+      auto vars_new = dlg.setOutput();
       std::vector<std::string>::const_iterator v_old = common.begin();
       std::vector<std::string>::const_iterator v_new = vars_new.begin();
       for(; v_old != common.end(); ++v_old,++v_new)