Const correctnes for QgsFeature in labeling

A feature is not modified while it's sent through the labeling pipeline.

Author: m-kuhn

python/core/auto_generated/qgspallabeling.sip.in

@@ -386,9 +386,9 @@ Returns the QgsExpression for this label settings. May be None if isExpression i
 
     double zIndex;
 
-    void calculateLabelSize( const QFontMetricsF *fm, QString text, double &labelX, double &labelY, QgsFeature *f = 0, QgsRenderContext *context = 0 );
+    void calculateLabelSize( const QFontMetricsF *fm, QString text, double &labelX, double &labelY, const QgsFeature *f = 0, QgsRenderContext *context = 0 );
 
-    void registerFeature( QgsFeature &f, QgsRenderContext &context  );
+    void registerFeature( const QgsFeature &f, QgsRenderContext &context  );
 
 %Docstring
 Register a feature for labeling.
@@ -457,7 +457,7 @@ Sets the label text formatting settings, e.g., font settings, buffer settings, e
 .. versionadded:: 3.0
 %End
 
-    QgsFeature *mCurFeat;
+    const QgsFeature *mCurFeat;
     QgsFields mCurFields;
     int fieldIndex;
     const QgsMapToPixel *xform;
@@ -469,7 +469,6 @@ Sets the label text formatting settings, e.g., font settings, buffer settings, e
     int mFeaturesToLabel;
     int mFeatsSendingToPal;
     int mFeatsRegPal;
-
 };
 
 class QgsLabelCandidate

src/core/dxf/qgsdxfpallabeling.cpp

@@ -34,7 +34,7 @@ void QgsDxfLabelProvider::drawLabel( QgsRenderContext &context, pal::LabelPositi
   mDxfExport->drawLabel( layerId(), context, label, mSettings );
 }
 
-void QgsDxfLabelProvider::registerDxfFeature( QgsFeature &feature, QgsRenderContext &context, const QString &dxfLayerName )
+void QgsDxfLabelProvider::registerDxfFeature( const QgsFeature &feature, QgsRenderContext &context, const QString &dxfLayerName )
 {
   registerFeature( feature, context );
   mDxfExport->registerDxfLayer( layerId(), feature.id(), dxfLayerName );

src/core/dxf/qgsdxfpallabeling.h

@@ -54,7 +54,7 @@ class QgsDxfLabelProvider : public QgsVectorLayerLabelProvider
      * \param context render context
      * \param dxfLayerName name of dxf layer
      */
-    void registerDxfFeature( QgsFeature &feature, QgsRenderContext &context, const QString &dxfLayerName );
+    void registerDxfFeature( const QgsFeature &feature, QgsRenderContext &context, const QString &dxfLayerName );
 
   protected:
     //! pointer to parent DXF export where this instance is used

src/core/qgspallabeling.cpp

@@ -1038,7 +1038,7 @@ bool QgsPalLayerSettings::checkMinimumSizeMM( const QgsRenderContext &ct, const
   return QgsPalLabeling::checkMinimumSizeMM( ct, geom, minSize );
 }
 
-void QgsPalLayerSettings::calculateLabelSize( const QFontMetricsF *fm, QString text, double &labelX, double &labelY, QgsFeature *f, QgsRenderContext *context )
+void QgsPalLayerSettings::calculateLabelSize( const QFontMetricsF *fm, QString text, double &labelX, double &labelY, const QgsFeature *f, QgsRenderContext *context )
 {
   if ( !fm || !f )
   {
@@ -1186,7 +1186,7 @@ void QgsPalLayerSettings::calculateLabelSize( const QFontMetricsF *fm, QString t
 #endif
 }
 
-void QgsPalLayerSettings::registerFeature( QgsFeature &f, QgsRenderContext &context, QgsLabelFeature **labelFeature, QgsGeometry obstacleGeometry )
+void QgsPalLayerSettings::registerFeature( const QgsFeature &f, QgsRenderContext &context, QgsLabelFeature **labelFeature, QgsGeometry obstacleGeometry )
 {
   // either used in QgsPalLabeling (palLayer is set) or in QgsLabelingEngine (labelFeature is set)
   Q_ASSERT( labelFeature );
@@ -1995,7 +1995,7 @@ void QgsPalLayerSettings::registerFeature( QgsFeature &f, QgsRenderContext &cont
   lf->setDataDefinedValues( dataDefinedValues );
 }
 
-void QgsPalLayerSettings::registerObstacleFeature( QgsFeature &f, QgsRenderContext &context, QgsLabelFeature **obstacleFeature, const QgsGeometry &obstacleGeometry )
+void QgsPalLayerSettings::registerObstacleFeature( const QgsFeature &f, QgsRenderContext &context, QgsLabelFeature **obstacleFeature, const QgsGeometry &obstacleGeometry )
 {
   mCurFeat = &f;
 

src/core/qgspallabeling.h

@@ -751,7 +751,7 @@ class CORE_EXPORT QgsPalLayerSettings
     double zIndex;
 
     // called from register feature hook
-    void calculateLabelSize( const QFontMetricsF *fm, QString text, double &labelX, double &labelY, QgsFeature *f = nullptr, QgsRenderContext *context = nullptr );
+    void calculateLabelSize( const QFontMetricsF *fm, QString text, double &labelX, double &labelY, const QgsFeature *f = nullptr, QgsRenderContext *context = nullptr );
 
     /**
      * Register a feature for labeling.
@@ -766,7 +766,7 @@ class CORE_EXPORT QgsPalLayerSettings
      * the feature's original geometry will be used as an obstacle for labels. Not available
      * in Python bindings.
      */
-    void registerFeature( QgsFeature &f, QgsRenderContext &context,
+    void registerFeature( const QgsFeature &f, QgsRenderContext &context,
                           QgsLabelFeature **labelFeature SIP_PYARGREMOVE = nullptr,
                           QgsGeometry obstacleGeometry SIP_PYARGREMOVE = QgsGeometry() );
 
@@ -823,7 +823,7 @@ class CORE_EXPORT QgsPalLayerSettings
     void setFormat( const QgsTextFormat &format ) { mFormat = format; }
 
     // temporary stuff: set when layer gets prepared or labeled
-    QgsFeature *mCurFeat = nullptr;
+    const QgsFeature *mCurFeat = nullptr;
     QgsFields mCurFields;
     int fieldIndex;
     const QgsMapToPixel *xform = nullptr;
@@ -835,7 +835,6 @@ class CORE_EXPORT QgsPalLayerSettings
     int mFeaturesToLabel = 0; // total features that will probably be labeled, may be less (figured before PAL)
     int mFeatsSendingToPal = 0; // total features tested for sending into PAL (relative to maxNumLabels)
     int mFeatsRegPal = 0; // number of features registered in PAL, when using limitNumLabels
-
   private:
 
     friend class QgsVectorLayer;  // to allow calling readFromLayerCustomProperties()
@@ -899,7 +898,7 @@ class CORE_EXPORT QgsPalLayerSettings
     /**
      * Registers a feature as an obstacle only (no label rendered)
      */
-    void registerObstacleFeature( QgsFeature &f, QgsRenderContext &context, QgsLabelFeature **obstacleFeature, const QgsGeometry &obstacleGeometry = QgsGeometry() );
+    void registerObstacleFeature( const QgsFeature &f, QgsRenderContext &context, QgsLabelFeature **obstacleFeature, const QgsGeometry &obstacleGeometry = QgsGeometry() );
 
     QMap<Property, QVariant> dataDefinedValues;
 

src/core/qgsrulebasedlabeling.cpp

@@ -37,7 +37,7 @@ bool QgsRuleBasedLabelProvider::prepare( const QgsRenderContext &context, QSet<Q
   return true;
 }
 
-void QgsRuleBasedLabelProvider::registerFeature( QgsFeature &feature, QgsRenderContext &context, const QgsGeometry &obstacleGeometry )
+void QgsRuleBasedLabelProvider::registerFeature( const QgsFeature &feature, QgsRenderContext &context, const QgsGeometry &obstacleGeometry )
 {
   // will register the feature to relevant sub-providers
   mRules->rootRule()->registerFeature( feature, context, mSubProviders, obstacleGeometry );
@@ -316,7 +316,7 @@ void QgsRuleBasedLabeling::Rule::prepare( const QgsRenderContext &context, QSet<
   }
 }
 
-QgsRuleBasedLabeling::Rule::RegisterResult QgsRuleBasedLabeling::Rule::registerFeature( QgsFeature &feature, QgsRenderContext &context, QgsRuleBasedLabeling::RuleToProviderMap &subProviders, const QgsGeometry &obstacleGeometry )
+QgsRuleBasedLabeling::Rule::RegisterResult QgsRuleBasedLabeling::Rule::registerFeature( const QgsFeature &feature, QgsRenderContext &context, QgsRuleBasedLabeling::RuleToProviderMap &subProviders, const QgsGeometry &obstacleGeometry )
 {
   if ( !isFilterOK( feature, context )
        || !isScaleOK( context.rendererScale() ) )
@@ -363,7 +363,7 @@ QgsRuleBasedLabeling::Rule::RegisterResult QgsRuleBasedLabeling::Rule::registerF
     return Filtered;
 }
 
-bool QgsRuleBasedLabeling::Rule::isFilterOK( QgsFeature &f, QgsRenderContext &context ) const
+bool QgsRuleBasedLabeling::Rule::isFilterOK( const QgsFeature &f, QgsRenderContext &context ) const
 {
   if ( ! mFilter || mElseRule )
     return true;

src/core/qgsrulebasedlabeling.h

@@ -282,7 +282,7 @@ class CORE_EXPORT QgsRuleBasedLabeling : public QgsAbstractVectorLayerLabeling
          * register individual features
          * \note not available in Python bindings
          */
-        RegisterResult registerFeature( QgsFeature &feature, QgsRenderContext &context, RuleToProviderMap &subProviders, const QgsGeometry &obstacleGeometry = QgsGeometry() ) SIP_SKIP;
+        RegisterResult registerFeature( const QgsFeature &feature, QgsRenderContext &context, RuleToProviderMap &subProviders, const QgsGeometry &obstacleGeometry = QgsGeometry() ) SIP_SKIP;
 
         /**
          * Returns true if this rule or any of its children requires advanced composition effects
@@ -302,7 +302,7 @@ class CORE_EXPORT QgsRuleBasedLabeling : public QgsAbstractVectorLayerLabeling
          * \param context   The context in which the rendering happens
          * \returns          True if the feature shall be rendered
          */
-        bool isFilterOK( QgsFeature &f, QgsRenderContext &context ) const;
+        bool isFilterOK( const QgsFeature &f, QgsRenderContext &context ) const;
 
         /**
          * Check if this rule applies for a given \a scale.
@@ -395,7 +395,7 @@ class CORE_EXPORT QgsRuleBasedLabelProvider : public QgsVectorLayerLabelProvider
 
     bool prepare( const QgsRenderContext &context, QSet<QString> &attributeNames ) override;
 
-    void registerFeature( QgsFeature &feature, QgsRenderContext &context, const QgsGeometry &obstacleGeometry = QgsGeometry() ) override;
+    void registerFeature( const QgsFeature &feature, QgsRenderContext &context, const QgsGeometry &obstacleGeometry = QgsGeometry() ) override;
 
     //! create a label provider
     virtual QgsVectorLayerLabelProvider *createProvider( QgsVectorLayer *layer, const QString &providerId, bool withFeatureLoop, const QgsPalLayerSettings *settings );

src/core/qgsvectorlayerlabelprovider.cpp

@@ -258,7 +258,7 @@ QList<QgsLabelFeature *> QgsVectorLayerLabelProvider::labelFeatures( QgsRenderCo
   return mLabels;
 }
 
-void QgsVectorLayerLabelProvider::registerFeature( QgsFeature &feature, QgsRenderContext &context, const QgsGeometry &obstacleGeometry )
+void QgsVectorLayerLabelProvider::registerFeature( const QgsFeature &feature, QgsRenderContext &context, const QgsGeometry &obstacleGeometry )
 {
   QgsLabelFeature *label = nullptr;
   mSettings.registerFeature( feature, context, &label, obstacleGeometry );

src/core/qgsvectorlayerlabelprovider.h

@@ -74,7 +74,7 @@ class CORE_EXPORT QgsVectorLayerLabelProvider : public QgsAbstractLabelProvider
      * symbol, the obstacle geometry should represent the bounds of the offset symbol). If not set,
      * the feature's original geometry will be used as an obstacle for labels.
      */
-    virtual void registerFeature( QgsFeature &feature, QgsRenderContext &context, const QgsGeometry &obstacleGeometry = QgsGeometry() );
+    virtual void registerFeature( const QgsFeature &feature, QgsRenderContext &context, const QgsGeometry &obstacleGeometry = QgsGeometry() );
 
     /**
      * Returns the geometry for a point feature which should be used as an obstacle for labels. This