loplugin:passstuffbyref in chart2

Change-Id: Id14015b1a02047c4d2e9d4ed4a9edfd0cb409c59

30 files changed, 57 insertions, 58 deletions

diff --git a/chart2/inc/ChartModel.hxx b/chart2/inc/ChartModel.hxx
index e3f9997a0535..b3caaad412c4 100644
--- a/chart2/inc/ChartModel.hxx
+++ b/chart2/inc/ChartModel.hxx
@@ -571,7 +571,7 @@ public:
     css::uno::Reference< css::util::XNumberFormatsSupplier >
         getNumberFormatsSupplier();
 
-    css::uno::Reference< css::uno::XInterface > getChartView() { return xChartView;}
+    const css::uno::Reference< css::uno::XInterface >& getChartView() { return xChartView;}
 
     bool isTimeBased() const { return mbTimeBased;}
     void setTimeBased(bool bTimeBased);
diff --git a/chart2/source/controller/inc/AccessibleBase.hxx b/chart2/source/controller/inc/AccessibleBase.hxx
index 2fbee3d54989..84351324a87b 100644
--- a/chart2/source/controller/inc/AccessibleBase.hxx
+++ b/chart2/source/controller/inc/AccessibleBase.hxx
@@ -214,7 +214,7 @@ protected:
 
     const AccessibleElementInfo& GetInfo() const { return m_aAccInfo;}
     void SetInfo( const AccessibleElementInfo & rNewInfo );
-    AccessibleUniqueId GetId() const { return m_aAccInfo.m_aOID;}
+    const AccessibleUniqueId& GetId() const { return m_aAccInfo.m_aOID;}
 
     // ________ WeakComponentImplHelper (XComponent::dispose) ________
     virtual void SAL_CALL disposing() override;
diff --git a/chart2/source/controller/inc/CharacterPropertyItemConverter.hxx b/chart2/source/controller/inc/CharacterPropertyItemConverter.hxx
index f62b0cf040db..1beea2ef1b12 100644
--- a/chart2/source/controller/inc/CharacterPropertyItemConverter.hxx
+++ b/chart2/source/controller/inc/CharacterPropertyItemConverter.hxx
@@ -51,7 +51,7 @@ protected:
     virtual bool ApplySpecialItem( sal_uInt16 nWhichId, const SfxItemSet & rItemSet )
         throw (css::uno::Exception) override;
 
-    css::uno::Reference<css::beans::XPropertySet> GetRefSizePropertySet() const;
+    const css::uno::Reference<css::beans::XPropertySet>& GetRefSizePropertySet() const;
 
 private:
     OUString m_aRefSizePropertyName;
diff --git a/chart2/source/controller/inc/ChartController.hxx b/chart2/source/controller/inc/ChartController.hxx
index f73d7e449370..1a226bb675f6 100644
--- a/chart2/source/controller/inc/ChartController.hxx
+++ b/chart2/source/controller/inc/ChartController.hxx
@@ -396,7 +396,7 @@ private:
             void        addListener( ChartController* pController );
             void        removeListener(  ChartController* pController );
             void        tryTermination();
-            css::uno::Reference< css::frame::XModel >
+            const css::uno::Reference< css::frame::XModel >&
                         getModel() const { return m_xModel;}
 
         private:
diff --git a/chart2/source/controller/inc/ChartDocumentWrapper.hxx b/chart2/source/controller/inc/ChartDocumentWrapper.hxx
index 8b5c8e111f25..b1212990b77a 100644
--- a/chart2/source/controller/inc/ChartDocumentWrapper.hxx
+++ b/chart2/source/controller/inc/ChartDocumentWrapper.hxx
@@ -73,13 +73,13 @@ public:
     static css::uno::Sequence< OUString > getSupportedServiceNames_Static();
 
     void setAddIn( const css::uno::Reference< css::util::XRefreshable >& xAddIn );
-    css::uno::Reference< css::util::XRefreshable > getAddIn() const { return m_xAddIn;}
+    const css::uno::Reference< css::util::XRefreshable >& getAddIn() const { return m_xAddIn;}
 
     void setUpdateAddIn( bool bUpdateAddIn );
     bool getUpdateAddIn() const { return m_bUpdateAddIn;}
 
     void setBaseDiagram( const OUString& rBaseDiagram );
-    OUString getBaseDiagram() const { return m_aBaseDiagram;}
+    const OUString& getBaseDiagram() const { return m_aBaseDiagram;}
 
     css::uno::Reference< css::drawing::XShapes > getAdditionalShapes() const;
 
diff --git a/chart2/source/controller/inc/ItemConverter.hxx b/chart2/source/controller/inc/ItemConverter.hxx
index 8ccc785549d5..612a56f034a8 100644
--- a/chart2/source/controller/inc/ItemConverter.hxx
+++ b/chart2/source/controller/inc/ItemConverter.hxx
@@ -167,7 +167,7 @@ protected:
     /** Returns the XPropertySet that was given in the CTOR and is used to apply
         items in ApplyItemSet().
      */
-    css::uno::Reference< css::beans::XPropertySet >  GetPropertySet() const { return m_xPropertySet;}
+    const css::uno::Reference< css::beans::XPropertySet >&  GetPropertySet() const { return m_xPropertySet;}
 
     // ____ ::utl::OEventListenerAdapter ____
     virtual void _disposing( const css::lang::EventObject& rSource ) override;
diff --git a/chart2/source/controller/inc/ObjectHierarchy.hxx b/chart2/source/controller/inc/ObjectHierarchy.hxx
index 8d653dd44521..bf36a91f2b95 100644
--- a/chart2/source/controller/inc/ObjectHierarchy.hxx
+++ b/chart2/source/controller/inc/ObjectHierarchy.hxx
@@ -84,7 +84,7 @@ public:
                                   ExplicitValueProvider * pExplicitValueProvider = nullptr );
 
     bool handleKeyEvent( const css::awt::KeyEvent & rEvent );
-    ObjectHierarchy::tOID getCurrentSelection() const { return m_aCurrentOID;}
+    const ObjectHierarchy::tOID& getCurrentSelection() const { return m_aCurrentOID;}
 
 private:
     void setCurrentSelection( const ObjectHierarchy::tOID& rOID );
diff --git a/chart2/source/controller/inc/SelectionHelper.hxx b/chart2/source/controller/inc/SelectionHelper.hxx
index a770a495a01c..e6257a0e6044 100644
--- a/chart2/source/controller/inc/SelectionHelper.hxx
+++ b/chart2/source/controller/inc/SelectionHelper.hxx
@@ -38,7 +38,7 @@ public: //methods
 
     OUString getSelectedCID();
     css::uno::Reference< css::drawing::XShape > getSelectedAdditionalShape();
-    ObjectIdentifier getSelectedOID() const { return m_aSelectedOID;}
+    const ObjectIdentifier& getSelectedOID() const { return m_aSelectedOID;}
 
     bool isResizeableObjectSelected();
     bool isRotateableObjectSelected( const css::uno::Reference< css::frame::XModel >& xChartModel );
diff --git a/chart2/source/controller/inc/dlg_ObjectProperties.hxx b/chart2/source/controller/inc/dlg_ObjectProperties.hxx
index 3ec0631d1b89..781ef20b8a62 100644
--- a/chart2/source/controller/inc/dlg_ObjectProperties.hxx
+++ b/chart2/source/controller/inc/dlg_ObjectProperties.hxx
@@ -35,7 +35,7 @@ public:
 
     void            init( const css::uno::Reference< css::frame::XModel >& xModel );
     ObjectType      getObjectType() const { return m_eObjectType;}
-    OUString   getLocalizedName() const { return m_aLocalizedName;}
+    const OUString& getLocalizedName() const { return m_aLocalizedName;}
 
     bool HasGeometryProperties() const { return m_bHasGeometryProperties;}
     bool HasStatisticProperties() const { return m_bHasStatisticProperties;}
@@ -55,7 +55,7 @@ public:
     bool IsCrossingAxisIsCategoryAxis() const { return m_bIsCrossingAxisIsCategoryAxis;}
     const css::uno::Sequence< OUString >& GetCategories() const { return m_aCategories;}
 
-    css::uno::Reference< css::chart2::XChartDocument >
+    const css::uno::Reference< css::chart2::XChartDocument >&
         getDocument() const { return m_xChartDocument;}
 
     bool IsComplexCategoriesAxis() const { return m_bComplexCategoriesAxis;}
diff --git a/chart2/source/controller/itemsetwrapper/CharacterPropertyItemConverter.cxx b/chart2/source/controller/itemsetwrapper/CharacterPropertyItemConverter.cxx
index 1991ef6baa51..5573ff699d02 100644
--- a/chart2/source/controller/itemsetwrapper/CharacterPropertyItemConverter.cxx
+++ b/chart2/source/controller/itemsetwrapper/CharacterPropertyItemConverter.cxx
@@ -552,7 +552,7 @@ bool CharacterPropertyItemConverter::ApplySpecialItem(
     return bChanged;
 }
 
-uno::Reference<beans::XPropertySet> CharacterPropertyItemConverter::GetRefSizePropertySet() const
+const uno::Reference<beans::XPropertySet>& CharacterPropertyItemConverter::GetRefSizePropertySet() const
 {
     return m_xRefSizePropSet;
 }
diff --git a/chart2/source/inc/InternalData.hxx b/chart2/source/inc/InternalData.hxx
index 26ec9fc40e67..9a7eb3587045 100644
--- a/chart2/source/inc/InternalData.hxx
+++ b/chart2/source/inc/InternalData.hxx
@@ -68,9 +68,9 @@ public:
     typedef ::std::vector< ::std::vector< css::uno::Any > > tVecVecAny; //inner index is hierarchical level
 
     void setComplexRowLabels( const tVecVecAny& rNewRowLabels );
-    tVecVecAny getComplexRowLabels() const;
+    const tVecVecAny& getComplexRowLabels() const;
     void setComplexColumnLabels( const tVecVecAny& rNewColumnLabels );
-    tVecVecAny getComplexColumnLabels() const;
+    const tVecVecAny& getComplexColumnLabels() const;
 
     void dump() const;
 
diff --git a/chart2/source/inc/MediaDescriptorHelper.hxx b/chart2/source/inc/MediaDescriptorHelper.hxx
index e1c573d58d12..f0180640c716 100644
--- a/chart2/source/inc/MediaDescriptorHelper.hxx
+++ b/chart2/source/inc/MediaDescriptorHelper.hxx
@@ -50,7 +50,7 @@ private:
 public:
     MediaDescriptorHelper( const css::uno::Sequence< css::beans::PropertyValue > & rMediaDescriptor );
 
-    css::uno::Sequence< css::beans::PropertyValue > getReducedForModel() { return m_aModelProperties;}
+    const css::uno::Sequence< css::beans::PropertyValue >& getReducedForModel() { return m_aModelProperties;}
 
 public:
     //all properties given in the constructor are stored in the following three sequences
diff --git a/chart2/source/inc/NumberFormatterWrapper.hxx b/chart2/source/inc/NumberFormatterWrapper.hxx
index ae9c40ca67ae..4743054ea3ac 100644
--- a/chart2/source/inc/NumberFormatterWrapper.hxx
+++ b/chart2/source/inc/NumberFormatterWrapper.hxx
@@ -37,7 +37,7 @@ public:
     virtual ~NumberFormatterWrapper();
 
     SvNumberFormatter* getSvNumberFormatter() const { return m_pNumberFormatter;}
-    css::uno::Reference< css::util::XNumberFormatsSupplier >
+    const css::uno::Reference< css::util::XNumberFormatsSupplier >&
                 getNumberFormatsSupplier() { return m_xNumberFormatsSupplier; };
 
     OUString getFormattedString( sal_Int32 nNumberFormatKey, double fValue, sal_Int32& rLabelColor, bool& rbColorChanged ) const;
diff --git a/chart2/source/inc/ObjectIdentifier.hxx b/chart2/source/inc/ObjectIdentifier.hxx
index a59c2e6b4c49..574b2c7cf0c5 100644
--- a/chart2/source/inc/ObjectIdentifier.hxx
+++ b/chart2/source/inc/ObjectIdentifier.hxx
@@ -246,8 +246,8 @@ public:
     bool isValid() const;
     bool isAutoGeneratedObject() const;
     bool isAdditionalShape() const;
-    OUString getObjectCID() const { return m_aObjectCID;}
-    css::uno::Reference< css::drawing::XShape > getAdditionalShape() const { return m_xAdditionalShape;}
+    const OUString& getObjectCID() const { return m_aObjectCID;}
+    const css::uno::Reference< css::drawing::XShape >& getAdditionalShape() const { return m_xAdditionalShape;}
     css::uno::Any getAny() const;
 
 private:
diff --git a/chart2/source/inc/ReferenceSizeProvider.hxx b/chart2/source/inc/ReferenceSizeProvider.hxx
index 02dac03b273e..a12b2f2800f8 100644
--- a/chart2/source/inc/ReferenceSizeProvider.hxx
+++ b/chart2/source/inc/ReferenceSizeProvider.hxx
@@ -50,7 +50,7 @@ public:
         css::awt::Size aPageSize,
         const css::uno::Reference< css::chart2::XChartDocument > & xChartDoc );
 
-    css::awt::Size getPageSize() const { return m_aPageSize;}
+    const css::awt::Size& getPageSize() const { return m_aPageSize;}
 
     /** Retrieves the state auto-resize from all objects that support this
         feature.  If all objects return the same state, AUTO_RESIZE_YES or
diff --git a/chart2/source/model/template/ChartType.hxx b/chart2/source/model/template/ChartType.hxx
index 0b94cd3ac1e4..653ce0f2ee1c 100644
--- a/chart2/source/model/template/ChartType.hxx
+++ b/chart2/source/model/template/ChartType.hxx
@@ -62,7 +62,7 @@ public:
 protected:
     explicit ChartType( const ChartType & rOther );
 
-    css::uno::Reference< css::uno::XComponentContext >
+    const css::uno::Reference< css::uno::XComponentContext >&
         GetComponentContext() const { return m_xContext;}
 
     // ____ XChartType ____
diff --git a/chart2/source/model/template/ChartTypeTemplate.hxx b/chart2/source/model/template/ChartTypeTemplate.hxx
index 19ac4873ca08..2f7bdcb26b41 100644
--- a/chart2/source/model/template/ChartTypeTemplate.hxx
+++ b/chart2/source/model/template/ChartTypeTemplate.hxx
@@ -230,7 +230,7 @@ protected:
     virtual void adaptAxes(
         const css::uno::Sequence< css::uno::Reference< css::chart2::XCoordinateSystem > > & rCoordSys );
 
-    css::uno::Reference< css::uno::XComponentContext >
+    const css::uno::Reference< css::uno::XComponentContext >&
         GetComponentContext() const { return m_xContext;}
 
     static void copyPropertiesFromOldToNewCoordinateSystem(
diff --git a/chart2/source/model/template/DataInterpreter.hxx b/chart2/source/model/template/DataInterpreter.hxx
index 1d903e96fc13..e9fd3e3ec042 100644
--- a/chart2/source/model/template/DataInterpreter.hxx
+++ b/chart2/source/model/template/DataInterpreter.hxx
@@ -35,7 +35,7 @@ public:
     explicit DataInterpreter( const css::uno::Reference< css::uno::XComponentContext > & xContext );
     virtual ~DataInterpreter();
 
-    css::uno::Reference< css::uno::XComponentContext >
+    const css::uno::Reference< css::uno::XComponentContext >&
         GetComponentContext() const { return m_xContext;}
 
     /// XServiceInfo declarations
diff --git a/chart2/source/tools/ImplOPropertySet.hxx b/chart2/source/tools/ImplOPropertySet.hxx
index 2bc7e6fe6895..dc015b0921a9 100644
--- a/chart2/source/tools/ImplOPropertySet.hxx
+++ b/chart2/source/tools/ImplOPropertySet.hxx
@@ -65,7 +65,7 @@ public:
                                    const css::uno::Any & rValue );
 
     bool SetStyle( const css::uno::Reference< css::style::XStyle > & xStyle );
-    css::uno::Reference< css::style::XStyle >
+    const css::uno::Reference< css::style::XStyle >&
         GetStyle() const { return m_xStyle;}
 
     typedef
diff --git a/chart2/source/tools/InternalData.cxx b/chart2/source/tools/InternalData.cxx
index 8e19da582462..a13424010cd1 100644
--- a/chart2/source/tools/InternalData.cxx
+++ b/chart2/source/tools/InternalData.cxx
@@ -481,7 +481,7 @@ void InternalData::setComplexRowLabels( const vector< vector< uno::Any > >& rNew
         enlargeData( 0, nNewRowCount );
 }
 
-InternalData::tVecVecAny InternalData::getComplexRowLabels() const
+const InternalData::tVecVecAny& InternalData::getComplexRowLabels() const
 {
     return m_aRowLabels;
 }
@@ -496,7 +496,7 @@ void InternalData::setComplexColumnLabels( const vector< vector< uno::Any > >& r
         enlargeData( nNewColumnCount, 0 );
 }
 
-InternalData::tVecVecAny InternalData::getComplexColumnLabels() const
+const InternalData::tVecVecAny& InternalData::getComplexColumnLabels() const
 {
     return m_aColumnLabels;
 }
diff --git a/chart2/source/tools/RegressionCurveModel.cxx b/chart2/source/tools/RegressionCurveModel.cxx
index 04e3160aed18..e74f1850dc22 100644
--- a/chart2/source/tools/RegressionCurveModel.cxx
+++ b/chart2/source/tools/RegressionCurveModel.cxx
@@ -376,7 +376,7 @@ OUString SAL_CALL MeanValueRegressionCurve::getImplementationName()
     return getImplementationName_Static();
 }
 
-OUString MeanValueRegressionCurve::getImplementationName_Static()
+const OUString& MeanValueRegressionCurve::getImplementationName_Static()
 {
     return lcl_aImplementationName_MeanValue;
 }
@@ -423,7 +423,7 @@ OUString SAL_CALL LinearRegressionCurve::getImplementationName()
     return getImplementationName_Static();
 }
 
-OUString LinearRegressionCurve::getImplementationName_Static()
+const OUString& LinearRegressionCurve::getImplementationName_Static()
 {
     return lcl_aImplementationName_Linear;
 }
@@ -470,7 +470,7 @@ OUString SAL_CALL LogarithmicRegressionCurve::getImplementationName()
     return getImplementationName_Static();
 }
 
-OUString LogarithmicRegressionCurve::getImplementationName_Static()
+const OUString& LogarithmicRegressionCurve::getImplementationName_Static()
 {
     return lcl_aImplementationName_Logarithmic;
 }
@@ -517,7 +517,7 @@ OUString SAL_CALL ExponentialRegressionCurve::getImplementationName()
     return getImplementationName_Static();
 }
 
-OUString ExponentialRegressionCurve::getImplementationName_Static()
+const OUString& ExponentialRegressionCurve::getImplementationName_Static()
 {
     return lcl_aImplementationName_Exponential;
 }
@@ -564,7 +564,7 @@ OUString SAL_CALL PotentialRegressionCurve::getImplementationName()
     return getImplementationName_Static();
 }
 
-OUString PotentialRegressionCurve::getImplementationName_Static()
+const OUString& PotentialRegressionCurve::getImplementationName_Static()
 {
     return lcl_aImplementationName_Potential;
 }
@@ -611,7 +611,7 @@ OUString SAL_CALL PolynomialRegressionCurve::getImplementationName()
     return getImplementationName_Static();
 }
 
-OUString PolynomialRegressionCurve::getImplementationName_Static()
+const OUString& PolynomialRegressionCurve::getImplementationName_Static()
 {
     return lcl_aImplementationName_Polynomial;
 }
@@ -658,7 +658,7 @@ OUString SAL_CALL MovingAverageRegressionCurve::getImplementationName()
     return getImplementationName_Static();
 }
 
-OUString MovingAverageRegressionCurve::getImplementationName_Static()
+const OUString& MovingAverageRegressionCurve::getImplementationName_Static()
 {
     return lcl_aImplementationName_MovingAverage;
 }
diff --git a/chart2/source/tools/RegressionCurveModel.hxx b/chart2/source/tools/RegressionCurveModel.hxx
index 5b03c5eaad57..35e63007d6d0 100644
--- a/chart2/source/tools/RegressionCurveModel.hxx
+++ b/chart2/source/tools/RegressionCurveModel.hxx
@@ -159,7 +159,7 @@ public:
     virtual css::uno::Sequence< OUString > SAL_CALL getSupportedServiceNames()
             throw( css::uno::RuntimeException, std::exception ) override;
 
-    static OUString getImplementationName_Static();
+    static const OUString& getImplementationName_Static();
     static css::uno::Sequence< OUString > getSupportedServiceNames_Static();
 };
 
@@ -185,7 +185,7 @@ public:
     virtual css::uno::Sequence< OUString > SAL_CALL getSupportedServiceNames()
             throw( css::uno::RuntimeException, std::exception ) override;
 
-    static OUString getImplementationName_Static();
+    static const OUString& getImplementationName_Static();
     static css::uno::Sequence< OUString > getSupportedServiceNames_Static();
 };
 
@@ -211,7 +211,7 @@ public:
     virtual css::uno::Sequence< OUString > SAL_CALL getSupportedServiceNames()
             throw( css::uno::RuntimeException, std::exception ) override;
 
-    static OUString getImplementationName_Static();
+    static const OUString& getImplementationName_Static();
     static css::uno::Sequence< OUString > getSupportedServiceNames_Static();
 };
 
@@ -236,7 +236,7 @@ public:
     virtual css::uno::Sequence< OUString > SAL_CALL getSupportedServiceNames()
             throw( css::uno::RuntimeException, std::exception ) override;
 
-    static OUString getImplementationName_Static();
+    static const OUString& getImplementationName_Static();
     static css::uno::Sequence< OUString > getSupportedServiceNames_Static();
 };
 
@@ -262,7 +262,7 @@ public:
     virtual css::uno::Sequence< OUString > SAL_CALL getSupportedServiceNames()
             throw( css::uno::RuntimeException, std::exception ) override;
 
-    static OUString getImplementationName_Static();
+    static const OUString& getImplementationName_Static();
     static css::uno::Sequence< OUString > getSupportedServiceNames_Static();
 };
 
@@ -287,7 +287,7 @@ public:
     virtual css::uno::Sequence< OUString > SAL_CALL getSupportedServiceNames()
             throw( css::uno::RuntimeException, std::exception ) override;
 
-    static OUString getImplementationName_Static();
+    static const OUString& getImplementationName_Static();
     static css::uno::Sequence< OUString > getSupportedServiceNames_Static();
 };
 
@@ -312,7 +312,7 @@ public:
     virtual css::uno::Sequence< OUString > SAL_CALL getSupportedServiceNames()
             throw( css::uno::RuntimeException, std::exception ) override;
 
-    static OUString getImplementationName_Static();
+    static const OUString& getImplementationName_Static();
     static css::uno::Sequence< OUString > getSupportedServiceNames_Static();
 };
 
diff --git a/chart2/source/view/axes/VAxisProperties.hxx b/chart2/source/view/axes/VAxisProperties.hxx
index c29e43f5f9aa..53d78c4c6a60 100644
--- a/chart2/source/view/axes/VAxisProperties.hxx
+++ b/chart2/source/view/axes/VAxisProperties.hxx
@@ -160,7 +160,7 @@ private:
     TickmarkProperties  makeTickmarkProperties( sal_Int32 nDepth ) const;
     //@todo get this from somewhere; maybe for each subincrement
     //so far the model does not offer different settings for each tick depth
-    VLineProperties      makeLinePropertiesForDepth( sal_Int32 /*nDepth*/ ) const { return m_aLineProperties; }
+    const VLineProperties&  makeLinePropertiesForDepth( sal_Int32 /*nDepth*/ ) const { return m_aLineProperties; }
 };
 
 } //namespace chart
diff --git a/chart2/source/view/inc/GL3DRenderer.hxx b/chart2/source/view/inc/GL3DRenderer.hxx
index 2c8008d30833..9966a9847f5a 100644
--- a/chart2/source/view/inc/GL3DRenderer.hxx
+++ b/chart2/source/view/inc/GL3DRenderer.hxx
@@ -214,9 +214,9 @@ public:
     void SetScrollSpeed(float scrollSpeed);
     void SetScrollDistance(float scrollDistance);
     void SetSceneEdge(float minCoordX, float maxCoordX);
-    glm::mat4 GetProjectionMatrix();
-    glm::mat4 GetViewMatrix();
-    glm::mat4 GetGlobalScaleMatrix();
+    const glm::mat4& GetProjectionMatrix();
+    const glm::mat4& GetViewMatrix();
+    const glm::mat4& GetGlobalScaleMatrix();
     glm::mat4 GetDiffOfTwoCameras(const glm::vec3& rBeginPos, const glm::vec3& rEndPos, const glm::vec3& rBeginDirection, const glm::vec3& rEndDirection);
     glm::mat4 GetDiffOfTwoCameras(const glm::vec3& rEndPos, const glm::vec3& rEndDirection);
     void AddMatrixDiff(const glm::mat4& aMat);
diff --git a/chart2/source/view/inc/PlottingPositionHelper.hxx b/chart2/source/view/inc/PlottingPositionHelper.hxx
index 1d60303b1791..a1911476e9d9 100644
--- a/chart2/source/view/inc/PlottingPositionHelper.hxx
+++ b/chart2/source/view/inc/PlottingPositionHelper.hxx
@@ -154,7 +154,7 @@ public:
     virtual void setTransformationSceneToScreen( const css::drawing::HomogenMatrix& rMatrix) override;
     virtual void setScales( const std::vector< ExplicitScaleData >& rScales, bool bSwapXAndYAxis ) override;
 
-    ::basegfx::B3DHomMatrix getUnitCartesianToScene() const { return m_aUnitCartesianToScene;}
+    const ::basegfx::B3DHomMatrix& getUnitCartesianToScene() const { return m_aUnitCartesianToScene;}
 
     virtual css::uno::Reference< css::chart2::XTransformation >
                   getTransformationScaledLogicToScene() const override;
diff --git a/chart2/source/view/inc/ScaleAutomatism.hxx b/chart2/source/view/inc/ScaleAutomatism.hxx
index 98c6ce114563..221612ab1aaa 100644
--- a/chart2/source/view/inc/ScaleAutomatism.hxx
+++ b/chart2/source/view/inc/ScaleAutomatism.hxx
@@ -96,8 +96,8 @@ public:
                             ExplicitScaleData& rExplicitScale,
                             ExplicitIncrementData& rExplicitIncrement ) const;
 
-    css::chart2::ScaleData getScale() const { return m_aSourceScale;}
-    Date getNullDate() const { return m_aNullDate;}
+    const css::chart2::ScaleData& getScale() const { return m_aSourceScale;}
+    const Date& getNullDate() const { return m_aNullDate;}
 
 private:
     /** Fills the passed scale data and increment data for category scaling. */
diff --git a/chart2/source/view/inc/VCoordinateSystem.hxx b/chart2/source/view/inc/VCoordinateSystem.hxx
index 15ceaa592f3d..41f15b70a432 100644
--- a/chart2/source/view/inc/VCoordinateSystem.hxx
+++ b/chart2/source/view/inc/VCoordinateSystem.hxx
@@ -60,7 +60,7 @@ public:
     void setParticle( const OUString& rCooSysParticle );
 
     void setTransformationSceneToScreen( const css::drawing::HomogenMatrix& rMatrix );
-    css::drawing::HomogenMatrix getTransformationSceneToScreen() { return m_aMatrixSceneToScreen;}
+    const css::drawing::HomogenMatrix& getTransformationSceneToScreen() { return m_aMatrixSceneToScreen;}
 
     //better performance for big data
     virtual css::uno::Sequence< sal_Int32 > getCoordinateSystemResolution( const css::awt::Size& rPageSize
@@ -103,8 +103,7 @@ public:
 
     void set3DWallPositions( CuboidPlanePosition eLeftWallPos, CuboidPlanePosition eBackWallPos, CuboidPlanePosition eBottomPos );
 
-    css::uno::Reference<
-        css::chart2::XCoordinateSystem >
+    const css::uno::Reference< css::chart2::XCoordinateSystem >&
         getModel() const { return m_xCooSysModel;}
 
     /**
diff --git a/chart2/source/view/inc/VDataSeries.hxx b/chart2/source/view/inc/VDataSeries.hxx
index 94586f402882..7231f0515338 100644
--- a/chart2/source/view/inc/VDataSeries.hxx
+++ b/chart2/source/view/inc/VDataSeries.hxx
@@ -65,7 +65,7 @@ public:
     VDataSeries(const VDataSeries&) = delete;
     const VDataSeries& operator=(const VDataSeries&) = delete;
 
-    css::uno::Reference<css::chart2::XDataSeries> getModel() const;
+    const css::uno::Reference<css::chart2::XDataSeries>& getModel() const;
 
     void setCategoryXAxis();
     void setXValues( const css::uno::Reference<css::chart2::data::XDataSequence>& xValues );
@@ -147,12 +147,12 @@ public:
     //this is here for deep stacking:
     double m_fLogicZPos;//from 0 to series count -1
 
-    OUString       getCID() const { return m_aCID;}
-    OUString       getSeriesParticle() const { return m_aSeriesParticle;}
-    OUString       getPointCID_Stub() const { return m_aPointCID_Stub;}
+    const OUString& getCID() const { return m_aCID;}
+    const OUString& getSeriesParticle() const { return m_aSeriesParticle;}
+    const OUString& getPointCID_Stub() const { return m_aPointCID_Stub;}
     OUString       getErrorBarsCID( bool bYError ) const;
     OUString       getLabelsCID() const;
-    OUString       getLabelCID_Stub() const { return m_aLabelCID_Stub;}
+    const OUString& getLabelCID_Stub() const { return m_aLabelCID_Stub;}
     OUString       getDataCurveCID( sal_Int32 nCurveIndex, bool bAverageLine ) const;
 
     css::chart2::DataPointLabel* getDataPointLabelIfLabel( sal_Int32 index ) const;
diff --git a/chart2/source/view/main/GL3DRenderer.cxx b/chart2/source/view/main/GL3DRenderer.cxx
index 98cacdaa16e3..1c2c635bd47a 100644
--- a/chart2/source/view/main/GL3DRenderer.cxx
+++ b/chart2/source/view/main/GL3DRenderer.cxx
@@ -2476,17 +2476,17 @@ glm::mat4 OpenGL3DRenderer::GetDiffOfTwoCameras(const glm::vec3& rEndPos, const
     return aEnd - m_3DView;
 }
 
-glm::mat4 OpenGL3DRenderer::GetProjectionMatrix()
+const glm::mat4& OpenGL3DRenderer::GetProjectionMatrix()
 {
     return m_3DProjection;
 }
 
-glm::mat4 OpenGL3DRenderer::GetViewMatrix()
+const glm::mat4& OpenGL3DRenderer::GetViewMatrix()
 {
     return m_3DView;
 }
 
-glm::mat4 OpenGL3DRenderer::GetGlobalScaleMatrix()
+const glm::mat4& OpenGL3DRenderer::GetGlobalScaleMatrix()
 {
     return m_GlobalScaleMatrix;
 }
diff --git a/chart2/source/view/main/VDataSeries.cxx b/chart2/source/view/main/VDataSeries.cxx
index 6d62e1b3d659..1b4748f82860 100644
--- a/chart2/source/view/main/VDataSeries.cxx
+++ b/chart2/source/view/main/VDataSeries.cxx
@@ -328,7 +328,7 @@ void VDataSeries::releaseShapes()
     m_nPolygonIndex = 0;
 }
 
-uno::Reference<css::chart2::XDataSeries> VDataSeries::getModel() const
+const uno::Reference<css::chart2::XDataSeries>& VDataSeries::getModel() const
 {
     return m_xDataSeries;
 }