dxf export: support rule based labeling (fixes #13757)

python/core/qgsmaprenderer.sip

@@ -35,7 +35,7 @@ class QgsLabelingEngineInterface
 
     //! called when we're going to start with rendering
     //! @deprecated since 2.4 - use override with QgsMapSettings
-    virtual void init( QgsMapRenderer* mp ) = 0 /Deprecated/;
+    virtual void init( QgsMapRenderer *mp ) = 0 /Deprecated/;
     //! called when we're going to start with rendering
     virtual void init( const QgsMapSettings& mapSettings ) = 0;
     //! called to find out whether the layer is used for labeling
@@ -48,17 +48,17 @@ class QgsLabelingEngineInterface
     virtual int prepareLayer( QgsVectorLayer* layer, QStringList& attrNames, QgsRenderContext& ctx ) = 0;
     //! returns PAL layer settings for a registered layer
     //! @deprecated since 2.12 - if direct access to QgsPalLayerSettings is necessary, use QgsPalLayerSettings::fromLayer()
-    virtual QgsPalLayerSettings& layer( const QString& layerName ) = 0 /Deprecated/;
+    virtual QgsPalLayerSettings &layer( const QString &layerName ) = 0 /Deprecated/;
     //! adds a diagram layer to the labeling engine
     //! @note added in QGIS 2.12
-    virtual int prepareDiagramLayer( QgsVectorLayer* layer, QStringList& attrNames, QgsRenderContext& ctx );
+    virtual int prepareDiagramLayer( QgsVectorLayer *layer, QStringList &attrNames, QgsRenderContext &ctx );
     //! adds a diagram layer to the labeling engine
     //! @deprecated since 2.12 - use prepareDiagramLayer()
-    virtual int addDiagramLayer( QgsVectorLayer* layer, const QgsDiagramLayerSettings* s ) /Deprecated/;
+    virtual int addDiagramLayer( QgsVectorLayer *layer, const QgsDiagramLayerSettings *s ) /Deprecated/;
     //! called for every feature
-    virtual void registerFeature( const QString& layerID, QgsFeature& feat, QgsRenderContext& context, const QString& dxfLayer = QString::null ) = 0;
+    virtual void registerFeature( const QString &layerID, QgsFeature &feat, QgsRenderContext &context ) = 0;
     //! called for every diagram feature
-    virtual void registerDiagramFeature( const QString& layerID, QgsFeature& feat, QgsRenderContext& context );
+    virtual void registerDiagramFeature( const QString &layerID, QgsFeature &feat, QgsRenderContext &context );
     //! called when the map is drawn and labels should be placed
     virtual void drawLabeling( QgsRenderContext& context ) = 0;
     //! called when we're done with rendering
@@ -268,7 +268,7 @@ class QgsMapRenderer : QObject
     //! Accessor for render context
     QgsRenderContext* rendererContext();
 
-    //! Labeling engine (NULL if there's no custom engine)
+    //! Labeling engine (nullptr if there's no custom engine)
     QgsLabelingEngineInterface* labelingEngine();
 
     //! Set labeling engine. Previous engine (if any) is deleted.

python/core/qgspallabeling.sip

@@ -551,7 +551,6 @@ class QgsPalLayerSettings
      * @param f feature to label
      * @param context render context. The QgsExpressionContext contained within the render context
      * must have already had the feature and fields sets prior to calling this method.
-     * @param dxfLayer dxfLayer name
      * @param labelFeature if using QgsLabelingEngineV2, this will receive the label feature. Not available
      * in Python bindings.
      * @param obstacleGeometry optional obstacle geometry, if a different geometry to the feature's geometry
@@ -560,7 +559,7 @@ class 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, const QString& dxfLayer );
+    void registerFeature( QgsFeature& f, QgsRenderContext& context );
 
     void readFromLayer( QgsVectorLayer* layer );
     void writeToLayer( QgsVectorLayer* layer );
@@ -867,9 +866,8 @@ class QgsPalLabeling : QgsLabelingEngineInterface
      * @param feat feature to label
      * @param context render context. The QgsExpressionContext contained within the render context
      * must have already had the feature and fields sets prior to calling this method.
-     * @param dxfLayer dxfLayer name
      */
-    virtual void registerFeature( const QString& layerID, QgsFeature& feat, QgsRenderContext& context, const QString& dxfLayer = QString::null );
+    virtual void registerFeature( const QString& layerID, QgsFeature& feat, QgsRenderContext& context );
 
     virtual void registerDiagramFeature( const QString& layerID, QgsFeature& feat, QgsRenderContext& context );
     //! called when the map is drawn and labels should be placed

src/core/dxf/qgsdxfexport.cpp

@@ -37,6 +37,11 @@
 #include "qgsvectorlayer.h"
 #include "qgsmaplayerregistry.h"
 #include "qgsunittypes.h"
+#include "qgstextlabelfeature.h"
+
+#include "pal/feature.h"
+#include "pal/pointset.h"
+#include "pal/labelposition.h"
 
 #include <QIODevice>
 
@@ -942,12 +947,32 @@ void QgsDxfExport::writeEntities()
         attributes << layerAttr;
     }
 
-    QgsDxfLabelProvider* lp = new QgsDxfLabelProvider( vl, this );
+    const QgsAbstractVectorLayerLabeling *labeling = vl->labeling();
-    engine.addProvider( lp );
+    QgsDxfLabelProvider *lp = nullptr;
-    if ( !lp->prepare( ctx, attributes ) )
+    QgsDxfRuleBasedLabelProvider *rblp = nullptr;
+    if ( dynamic_cast<const QgsRuleBasedLabeling*>( labeling ) )
     {
-      engine.removeProvider( lp );
+      const QgsRuleBasedLabeling *rbl = dynamic_cast<const QgsRuleBasedLabeling*>( labeling );
-      lp = nullptr;
+      rblp = new QgsDxfRuleBasedLabelProvider( *rbl, vl, this );
+      rblp->reinit( vl );
+      engine.addProvider( rblp );
+
+      if ( !rblp->prepare( ctx, attributes ) )
+      {
+        engine.removeProvider( rblp );
+        rblp = nullptr;
+      }
+    }
+    else
+    {
+      lp = new QgsDxfLabelProvider( vl, this, nullptr );
+      engine.addProvider( lp );
+
+      if ( !lp->prepare( ctx, attributes ) )
+      {
+        engine.removeProvider( lp );
+        lp = nullptr;
+      }
     }
 
     if ( mSymbologyExport == QgsDxfExport::SymbolLayerSymbology &&
@@ -1012,6 +1037,10 @@ void QgsDxfExport::writeEntities()
         {
           lp->registerDxfFeature( fet, ctx, lName );
         }
+        else if ( rblp )
+        {
+          rblp->registerDxfFeature( fet, ctx, lName );
+        }
       }
     }
 
@@ -4169,3 +4198,112 @@ QString QgsDxfExport::layerName( QgsVectorLayer *vl ) const
   Q_ASSERT( vl );
   return mLayerTitleAsName && !vl->title().isEmpty() ? vl->title() : vl->name();
 }
+
+void QgsDxfExport::drawLabel( QString layerId, QgsRenderContext& context, pal::LabelPosition* label, const QgsPalLayerSettings &settings )
+{
+  Q_UNUSED( context );
+  QgsTextLabelFeature* lf = dynamic_cast<QgsTextLabelFeature*>( label->getFeaturePart()->feature() );
+  if ( !lf )
+    return;
+
+  //label text
+  QString txt = lf->text( label->getPartId() );
+
+  //angle
+  double angle = label->getAlpha() * 180 / M_PI;
+
+  QgsFeatureId fid = label->getFeaturePart()->featureId();
+  QString dxfLayer = mDxfLayerNames[layerId][fid];
+
+  //debug: show label rectangle
+#if 0
+  QgsPolyline line;
+  for ( int i = 0; i < 4; ++i )
+  {
+    line.append( QgsPoint( label->getX( i ), label->getY( i ) ) );
+  }
+  writePolyline( line, dxfLayer, "CONTINUOUS", 1, 0.01, true );
+#endif
+
+  QString wrapchr = settings.wrapChar.isEmpty() ? "\n" : settings.wrapChar;
+
+  //add the direction symbol if needed
+  if ( !txt.isEmpty() && settings.placement == QgsPalLayerSettings::Line && settings.addDirectionSymbol )
+  {
+    bool prependSymb = false;
+    QString symb = settings.rightDirectionSymbol;
+
+    if ( label->getReversed() )
+    {
+      prependSymb = true;
+      symb = settings.leftDirectionSymbol;
+    }
+
+    if ( settings.reverseDirectionSymbol )
+    {
+      if ( symb == settings.rightDirectionSymbol )
+      {
+        prependSymb = true;
+        symb = settings.leftDirectionSymbol;
+      }
+      else
+      {
+        prependSymb = false;
+        symb = settings.rightDirectionSymbol;
+      }
+    }
+
+    if ( settings.placeDirectionSymbol == QgsPalLayerSettings::SymbolAbove )
+    {
+      prependSymb = true;
+      symb = symb + wrapchr;
+    }
+    else if ( settings.placeDirectionSymbol == QgsPalLayerSettings::SymbolBelow )
+    {
+      prependSymb = false;
+      symb = wrapchr + symb;
+    }
+
+    if ( prependSymb )
+    {
+      txt.prepend( symb );
+    }
+    else
+    {
+      txt.append( symb );
+    }
+  }
+
+  txt = txt.replace( wrapchr, "\\P" );
+
+  if ( settings.textFont.underline() )
+  {
+    txt.prepend( "\\L" ).append( "\\l" );
+  }
+
+  if ( settings.textFont.overline() )
+  {
+    txt.prepend( "\\O" ).append( "\\o" );
+  }
+
+  if ( settings.textFont.strikeOut() )
+  {
+    txt.prepend( "\\K" ).append( "\\k" );
+  }
+
+  txt.prepend( QString( "\\f%1|i%2|b%3;\\H%4;\\W0.75;" )
+               .arg( settings.textFont.family() )
+               .arg( settings.textFont.italic() ? 1 : 0 )
+               .arg( settings.textFont.bold() ? 1 : 0 )
+               .arg( label->getHeight() / ( 1 + txt.count( "\\P" ) ) * 0.75 ) );
+
+  writeMText( dxfLayer, txt, QgsPoint( label->getX(), label->getY() ), label->getWidth() * 1.1, angle, settings.textColor );
+}
+
+void QgsDxfExport::registerDxfLayer( QString layerId, QgsFeatureId fid, QString layerName )
+{
+  if ( !mDxfLayerNames.contains( layerId ) )
+    mDxfLayerNames[ layerId ] = QMap<QgsFeatureId, QString>();
+
+  mDxfLayerNames[layerId][fid] = layerName;
+}

src/core/dxf/qgsdxfexport.h

@@ -20,6 +20,7 @@
 
 #include "qgsgeometry.h"
 #include "qgssymbolv2.h"
+
 #include <QColor>
 #include <QList>
 #include <QTextStream>
@@ -28,6 +29,12 @@ class QgsMapLayer;
 class QgsPoint;
 class QgsSymbolLayerV2;
 class QIODevice;
+class QgsPalLayerSettings;
+
+namespace pal
+{
+  class LabelPosition;
+};
 
 class CORE_EXPORT QgsDxfExport
 {
@@ -283,6 +290,9 @@ class CORE_EXPORT QgsDxfExport
     //! return list of available DXF encodings
     static QStringList encodings();
 
+    void drawLabel( QString layerId, QgsRenderContext& context, pal::LabelPosition* label, const QgsPalLayerSettings &settings );
+    void registerDxfLayer( QString layerId, QgsFeatureId fid, QString layer );
+
   private:
     QList< QPair<QgsVectorLayer*, int> > mLayers;
 
@@ -350,6 +360,9 @@ class CORE_EXPORT QgsDxfExport
 
     QHash<QString, int> mBlockHandles;
     QString mBlockHandle;
+
+    //! DXF layer name for each label feature
+    QMap< QString, QMap<QgsFeatureId, QString> > mDxfLayerNames;
 };
 
 #endif // QGSDXFEXPORT_H

src/core/dxf/qgsdxfpallabeling.cpp

@@ -17,131 +17,57 @@
 
 #include "qgsdxfpallabeling.h"
 #include "qgsdxfexport.h"
-#include "qgstextlabelfeature.h"
 #include "qgspallabeling.h"
 #include "qgsmapsettings.h"
-
+#include "qgslogger.h"
-#include "pal/feature.h"
-#include "pal/pointset.h"
-#include "pal/labelposition.h"
 
 
-QgsDxfLabelProvider::QgsDxfLabelProvider( QgsVectorLayer* layer , QgsDxfExport* dxf )
+QgsDxfLabelProvider::QgsDxfLabelProvider( QgsVectorLayer* layer, QgsDxfExport* dxf, const QgsPalLayerSettings *settings )
-    : QgsVectorLayerLabelProvider( layer, false )
+    : QgsVectorLayerLabelProvider( layer, false, settings )
     , mDxfExport( dxf )
 {
 }
 
 void QgsDxfLabelProvider::drawLabel( QgsRenderContext& context, pal::LabelPosition* label ) const
 {
-  Q_UNUSED( context );
+  Q_ASSERT( mDxfExport );
-
+  mDxfExport->drawLabel( layerId(), context, label, mSettings );
-  //debug: print label infos
-  if ( mDxfExport )
-  {
-    QgsTextLabelFeature* lf = dynamic_cast<QgsTextLabelFeature*>( label->getFeaturePart()->feature() );
-    if ( !lf )
-      return;
-
-    const QgsPalLayerSettings& tmpLyr = mSettings;
-
-    //label text
-    QString txt = lf->text( label->getPartId() );
-
-    //angle
-    double angle = label->getAlpha() * 180 / M_PI;
-
-    QgsFeatureId fid = label->getFeaturePart()->featureId();
-    QString dxfLayer = mDxfLayerNames[fid];
-
-    //debug: show label rectangle
-#if 0
-    QgsPolyline line;
-    for ( int i = 0; i < 4; ++i )
-    {
-      line.append( QgsPoint( label->getX( i ), label->getY( i ) ) );
-    }
-    mDxfExport->writePolyline( line, dxfLayer, "CONTINUOUS", 1, 0.01, true );
-#endif
-
-    QString wrapchr = tmpLyr.wrapChar.isEmpty() ? "\n" : tmpLyr.wrapChar;
-
-    //add the direction symbol if needed
-    if ( !txt.isEmpty() && tmpLyr.placement == QgsPalLayerSettings::Line && tmpLyr.addDirectionSymbol )
-    {
-      bool prependSymb = false;
-      QString symb = tmpLyr.rightDirectionSymbol;
-
-      if ( label->getReversed() )
-      {
-        prependSymb = true;
-        symb = tmpLyr.leftDirectionSymbol;
-      }
-
-      if ( tmpLyr.reverseDirectionSymbol )
-      {
-        if ( symb == tmpLyr.rightDirectionSymbol )
-        {
-          prependSymb = true;
-          symb = tmpLyr.leftDirectionSymbol;
-        }
-        else
-        {
-          prependSymb = false;
-          symb = tmpLyr.rightDirectionSymbol;
-        }
-      }
-
-      if ( tmpLyr.placeDirectionSymbol == QgsPalLayerSettings::SymbolAbove )
-      {
-        prependSymb = true;
-        symb = symb + wrapchr;
-      }
-      else if ( tmpLyr.placeDirectionSymbol == QgsPalLayerSettings::SymbolBelow )
-      {
-        prependSymb = false;
-        symb = wrapchr + symb;
-      }
-
-      if ( prependSymb )
-      {
-        txt.prepend( symb );
-      }
-      else
-      {
-        txt.append( symb );
-      }
-    }
-
-    txt = txt.replace( wrapchr, "\\P" );
-
-    if ( tmpLyr.textFont.underline() )
-    {
-      txt.prepend( "\\L" ).append( "\\l" );
-    }
-
-    if ( tmpLyr.textFont.overline() )
-    {
-      txt.prepend( "\\O" ).append( "\\o" );
-    }
-
-    if ( tmpLyr.textFont.strikeOut() )
-    {
-      txt.prepend( "\\K" ).append( "\\k" );
-    }
-
-    txt.prepend( QString( "\\f%1|i%2|b%3;\\H%4;\\W0.75;" )
-                 .arg( tmpLyr.textFont.family() )
-                 .arg( tmpLyr.textFont.italic() ? 1 : 0 )
-                 .arg( tmpLyr.textFont.bold() ? 1 : 0 )
-                 .arg( label->getHeight() / ( 1 + txt.count( "\\P" ) ) * 0.75 ) );
-
-    mDxfExport->writeMText( dxfLayer, txt, QgsPoint( label->getX(), label->getY() ), label->getWidth() * 1.1, angle, tmpLyr.textColor );
-  }
 }
 
 void QgsDxfLabelProvider::registerDxfFeature( QgsFeature& feature, QgsRenderContext& context, const QString& dxfLayerName )
 {
   registerFeature( feature, context );
-  mDxfLayerNames[feature.id()] = dxfLayerName;
+  mDxfExport->registerDxfLayer( layerId(), feature.id(), dxfLayerName );
+}
+
+QgsDxfRuleBasedLabelProvider::QgsDxfRuleBasedLabelProvider( const QgsRuleBasedLabeling &rules, QgsVectorLayer* layer, QgsDxfExport* dxf )
+    : QgsRuleBasedLabelProvider( rules, layer, false )
+    , mDxfExport( dxf )
+{
+}
+
+void QgsDxfRuleBasedLabelProvider::reinit( QgsVectorLayer* layer )
+{
+  QgsDebugMsg( "Entering." );
+  mRules.rootRule()->createSubProviders( layer, mSubProviders, this );
+}
+
+QgsVectorLayerLabelProvider *QgsDxfRuleBasedLabelProvider::createProvider( QgsVectorLayer *layer, bool withFeatureLoop, const QgsPalLayerSettings *settings )
+{
+  QgsDebugMsg( "Entering." );
+  Q_UNUSED( withFeatureLoop );
+  return new QgsDxfLabelProvider( layer, mDxfExport, settings );
+}
+
+void QgsDxfRuleBasedLabelProvider::drawLabel( QgsRenderContext &context, pal::LabelPosition *label ) const
+{
+  QgsDebugMsg( "Entering." );
+  Q_ASSERT( mDxfExport );
+  mDxfExport->drawLabel( layerId(), context, label, mSettings );
+}
+
+void QgsDxfRuleBasedLabelProvider::registerDxfFeature( QgsFeature &feature, QgsRenderContext &context, const QString &dxfLayerName )
+{
+  registerFeature( feature, context );
+  mDxfExport->registerDxfLayer( layerId(), feature.id(), dxfLayerName );
 }

src/core/dxf/qgsdxfpallabeling.h

@@ -21,8 +21,11 @@
 #include "qgsmaprenderer.h"
 #include "qgsrendercontext.h"
 #include "qgsvectorlayerlabelprovider.h"
+#include "qgsrulebasedlabeling.h"
 
 class QgsDxfExport;
+class QgsPalLayerSettings;
+class QgsRuleBasedLabeling;
 
 
 /** Implements a derived label provider internally used for DXF export
@@ -34,10 +37,10 @@ class QgsDxfLabelProvider : public QgsVectorLayerLabelProvider
 {
   public:
     //! construct the provider
-    explicit QgsDxfLabelProvider( QgsVectorLayer* layer, QgsDxfExport* dxf );
+    explicit QgsDxfLabelProvider( QgsVectorLayer* layer, QgsDxfExport* dxf, const QgsPalLayerSettings *settings );
 
     //! re-implementation that writes to DXF file instead of drawing with QPainter
-    virtual void drawLabel( QgsRenderContext& context, pal::LabelPosition* label ) const override;
+    void drawLabel( QgsRenderContext& context, pal::LabelPosition* label ) const override;
 
     //! registration method that keeps track of DXF layer names of individual features
     void registerDxfFeature( QgsFeature& feature, QgsRenderContext &context, const QString& dxfLayerName );
@@ -45,8 +48,29 @@ class QgsDxfLabelProvider : public QgsVectorLayerLabelProvider
   protected:
     //! pointer to parent DXF export where this instance is used
     QgsDxfExport* mDxfExport;
-    //! DXF layer name for each label feature
-    QMap<QgsFeatureId, QString> mDxfLayerNames;
 };
 
+class QgsDxfRuleBasedLabelProvider : public QgsRuleBasedLabelProvider
+{
+  public:
+    //! construct the provider
+    explicit QgsDxfRuleBasedLabelProvider( const QgsRuleBasedLabeling &rules, QgsVectorLayer* layer, QgsDxfExport* dxf );
+
+    void reinit( QgsVectorLayer* layer );
+
+    //! re-implementation that writes to DXF file instead of drawing with QPainter
+    void drawLabel( QgsRenderContext &context, pal::LabelPosition *label ) const override;
+
+    //! registration method that keeps track of DXF layer names of individual features
+    void registerDxfFeature( QgsFeature& feature, QgsRenderContext &context, const QString& dxfLayerName );
+
+    virtual QgsVectorLayerLabelProvider *createProvider( QgsVectorLayer *layer, bool withFeatureLoop, const QgsPalLayerSettings *settings ) override;
+
+  protected:
+    //! pointer to parent DXF export where this instance is used
+    QgsDxfExport* mDxfExport;
+};
+
+
+
 #endif // QGSDXFPALLABELING_H

src/core/qgslabelfeature.cpp

@@ -13,7 +13,6 @@
  *                                                                         *
  ***************************************************************************/
 #include "qgslabelfeature.h"
-
 #include "feature.h"
 
 

src/core/qgsmaprenderer.h

@@ -46,9 +46,10 @@ class QgsDiagramLayerSettings;
 class CORE_EXPORT QgsLabelPosition
 {
   public:
-    QgsLabelPosition( int id, double r, const QVector< QgsPoint >& corners, const QgsRectangle& rect, double w, double h, const QString& layer, const QString& labeltext, const QFont& labelfont, bool upside_down, bool diagram = false, bool pinned = false ):
+    QgsLabelPosition( int id, double r, const QVector< QgsPoint >& corners, const QgsRectangle& rect, double w, double h, const QString& layer, const QString& labeltext, const QFont& labelfont, bool upside_down, bool diagram = false, bool pinned = false )
-        featureId( id ), rotation( r ), cornerPoints( corners ), labelRect( rect ), width( w ), height( h ), layerID( layer ), labelText( labeltext ), labelFont( labelfont ), upsideDown( upside_down ), isDiagram( diagram ), isPinned( pinned ) {}
+        : featureId( id ), rotation( r ), cornerPoints( corners ), labelRect( rect ), width( w ), height( h ), layerID( layer ), labelText( labeltext ), labelFont( labelfont ), upsideDown( upside_down ), isDiagram( diagram ), isPinned( pinned ) {}
-    QgsLabelPosition(): featureId( -1 ), rotation( 0 ), labelRect( QgsRectangle() ), width( 0 ), height( 0 ), layerID( "" ), labelText( "" ), labelFont( QFont() ), upsideDown( false ), isDiagram( false ), isPinned( false ) {}
+    QgsLabelPosition()
+        : featureId( -1 ), rotation( 0 ), labelRect( QgsRectangle() ), width( 0 ), height( 0 ), layerID( "" ), labelText( "" ), labelFont( QFont() ), upsideDown( false ), isDiagram( false ), isPinned( false ) {}
     int featureId;
     double rotation;
     QVector< QgsPoint > cornerPoints;
@@ -72,7 +73,7 @@ class CORE_EXPORT QgsLabelingEngineInterface
 
     //! called when we're going to start with rendering
     //! @deprecated since 2.4 - use override with QgsMapSettings
-    Q_DECL_DEPRECATED virtual void init( QgsMapRenderer* mp ) = 0;
+    Q_DECL_DEPRECATED virtual void init( QgsMapRenderer *mp ) = 0;
     //! called when we're going to start with rendering
     virtual void init( const QgsMapSettings& mapSettings ) = 0;
     //! called to find out whether the layer is used for labeling
@@ -85,19 +86,19 @@ class CORE_EXPORT QgsLabelingEngineInterface
     virtual int prepareLayer( QgsVectorLayer* layer, QStringList& attrNames, QgsRenderContext& ctx ) = 0;
     //! returns PAL layer settings for a registered layer
     //! @deprecated since 2.12 - if direct access to QgsPalLayerSettings is necessary, use QgsPalLayerSettings::fromLayer()
-    Q_DECL_DEPRECATED virtual QgsPalLayerSettings& layer( const QString& layerName ) = 0;
+    Q_DECL_DEPRECATED virtual QgsPalLayerSettings &layer( const QString &layerName ) = 0;
     //! adds a diagram layer to the labeling engine
     //! @note added in QGIS 2.12
-    virtual int prepareDiagramLayer( QgsVectorLayer* layer, QStringList& attrNames, QgsRenderContext& ctx )
+    virtual int prepareDiagramLayer( QgsVectorLayer *layer, QStringList &attrNames, QgsRenderContext &ctx )
     { Q_UNUSED( layer ); Q_UNUSED( attrNames ); Q_UNUSED( ctx ); return 0; }
     //! adds a diagram layer to the labeling engine
     //! @deprecated since 2.12 - use prepareDiagramLayer()
-    Q_DECL_DEPRECATED virtual int addDiagramLayer( QgsVectorLayer* layer, const QgsDiagramLayerSettings* s )
+    Q_DECL_DEPRECATED virtual int addDiagramLayer( QgsVectorLayer *layer, const QgsDiagramLayerSettings *s )
     { Q_UNUSED( layer ); Q_UNUSED( s ); return 0; }
     //! called for every feature
-    virtual void registerFeature( const QString& layerID, QgsFeature& feat, QgsRenderContext& context, const QString& dxfLayer = QString::null ) = 0;
+    virtual void registerFeature( const QString &layerID, QgsFeature &feat, QgsRenderContext &context ) = 0;
     //! called for every diagram feature
-    virtual void registerDiagramFeature( const QString& layerID, QgsFeature& feat, QgsRenderContext& context )
+    virtual void registerDiagramFeature( const QString &layerID, QgsFeature &feat, QgsRenderContext &context )
     { Q_UNUSED( layerID ); Q_UNUSED( feat ); Q_UNUSED( context ); }
     //! called when the map is drawn and labels should be placed
     virtual void drawLabeling( QgsRenderContext& context ) = 0;

src/core/qgspallabeling.cpp

@@ -1939,13 +1939,11 @@ void QgsPalLayerSettings::calculateLabelSize( const QFontMetricsF* fm, QString t
 #endif
 }
 
-void QgsPalLayerSettings::registerFeature( QgsFeature& f, QgsRenderContext &context, const QString& dxfLayer, QgsLabelFeature** labelFeature , QgsGeometry* obstacleGeometry )
+void QgsPalLayerSettings::registerFeature( QgsFeature& f, QgsRenderContext &context, QgsLabelFeature** labelFeature , QgsGeometry* obstacleGeometry )
 {
   // either used in QgsPalLabeling (palLayer is set) or in QgsLabelingEngineV2 (labelFeature is set)
   Q_ASSERT( labelFeature );
 
-  Q_UNUSED( dxfLayer ); // now handled in QgsDxfLabelProvider
-
   QVariant exprVal; // value() is repeatedly nulled on data defined evaluation and replaced when successful
   mCurFeat = &f;
 
@@ -1960,7 +1958,7 @@ void QgsPalLayerSettings::registerFeature( QgsFeature& f, QgsRenderContext &cont
   {
     if ( isObstacle )
     {
-      registerObstacleFeature( f, context, QString(), labelFeature, obstacleGeometry );
+      registerObstacleFeature( f, context, labelFeature, obstacleGeometry );
     }
     return;
   }
@@ -2812,10 +2810,8 @@ void QgsPalLayerSettings::registerFeature( QgsFeature& f, QgsRenderContext &cont
   lf->setDataDefinedValues( dataDefinedValues );
 }
 
-void QgsPalLayerSettings::registerObstacleFeature( QgsFeature& f, QgsRenderContext &context, const QString& dxfLayer, QgsLabelFeature** obstacleFeature, QgsGeometry* obstacleGeometry )
+void QgsPalLayerSettings::registerObstacleFeature( QgsFeature& f, QgsRenderContext &context, QgsLabelFeature** obstacleFeature, QgsGeometry* obstacleGeometry )
 {
-  Q_UNUSED( dxfLayer ); // now handled in QgsDxfLabelProvider
-
   mCurFeat = &f;
 
   const QgsGeometry* geom = nullptr;
@@ -3809,9 +3805,8 @@ int QgsPalLabeling::addDiagramLayer( QgsVectorLayer* layer, const QgsDiagramLaye
   return 0;
 }
 
-void QgsPalLabeling::registerFeature( const QString& layerID, QgsFeature& f, QgsRenderContext &context, const QString& dxfLayer )
+void QgsPalLabeling::registerFeature( const QString& layerID, QgsFeature& f, QgsRenderContext &context )
 {
-  Q_UNUSED( dxfLayer ); // now handled by QgsDxfLabelProvider
   if ( QgsVectorLayerLabelProvider* provider = mLabelProviders.value( layerID, nullptr ) )
     provider->registerFeature( f, context );
 }

src/core/qgspallabeling.h

@@ -533,7 +533,6 @@ class CORE_EXPORT QgsPalLayerSettings
      * @param f feature to label
      * @param context render context. The QgsExpressionContext contained within the render context
      * must have already had the feature and fields sets prior to calling this method.
-     * @param dxfLayer dxfLayer name
      * @param labelFeature if using QgsLabelingEngineV2, this will receive the label feature. Not available
      * in Python bindings.
      * @param obstacleGeometry optional obstacle geometry, if a different geometry to the feature's geometry
@@ -542,7 +541,7 @@ 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, const QString& dxfLayer, QgsLabelFeature** labelFeature = nullptr, QgsGeometry* obstacleGeometry = nullptr );
+    void registerFeature( QgsFeature& f, QgsRenderContext& context, QgsLabelFeature** labelFeature = nullptr, QgsGeometry* obstacleGeometry = nullptr );
 
     void readFromLayer( QgsVectorLayer* layer );
     void writeToLayer( QgsVectorLayer* layer );
@@ -712,7 +711,7 @@ class CORE_EXPORT QgsPalLayerSettings
 
     /** Registers a feature as an obstacle only (no label rendered)
      */
-    void registerObstacleFeature( QgsFeature &f, QgsRenderContext &context, const QString& dxfLayer, QgsLabelFeature** obstacleFeature, QgsGeometry* obstacleGeometry = nullptr );
+    void registerObstacleFeature( QgsFeature &f, QgsRenderContext &context, QgsLabelFeature** obstacleFeature, QgsGeometry* obstacleGeometry = nullptr );
 
     QMap<DataDefinedProperties, QVariant> dataDefinedValues;
     QgsExpression* expression;
@@ -949,9 +948,8 @@ class CORE_EXPORT QgsPalLabeling : public QgsLabelingEngineInterface
      * @param feat feature to label
      * @param context render context. The QgsExpressionContext contained within the render context
      * must have already had the feature and fields sets prior to calling this method.
-     * @param dxfLayer dxfLayer name
      */
-    virtual void registerFeature( const QString& layerID, QgsFeature& feat, QgsRenderContext& context, const QString& dxfLayer = QString::null ) override;
+    virtual void registerFeature( const QString& layerID, QgsFeature& feat, QgsRenderContext& context ) override;
 
     virtual void registerDiagramFeature( const QString& layerID, QgsFeature& feat, QgsRenderContext& context ) override;
     //! called when the map is drawn and labels should be placed

src/core/qgsrulebasedlabeling.cpp

@@ -15,12 +15,11 @@
 #include "qgsrulebasedlabeling.h"
 
 
-
 QgsRuleBasedLabelProvider::QgsRuleBasedLabelProvider( const QgsRuleBasedLabeling& rules, QgsVectorLayer* layer, bool withFeatureLoop )
     : QgsVectorLayerLabelProvider( layer, withFeatureLoop )
     , mRules( rules )
 {
-  mRules.rootRule()->createSubProviders( layer, mSubProviders );
+  mRules.rootRule()->createSubProviders( layer, mSubProviders, this );
 }
 
 QgsRuleBasedLabelProvider::~QgsRuleBasedLabelProvider()
@@ -28,6 +27,10 @@ QgsRuleBasedLabelProvider::~QgsRuleBasedLabelProvider()
   // sub-providers owned by labeling engine
 }
 
+QgsVectorLayerLabelProvider *QgsRuleBasedLabelProvider::createProvider( QgsVectorLayer *layer, bool withFeatureLoop, const QgsPalLayerSettings *settings )
+{
+  return new QgsVectorLayerLabelProvider( layer, withFeatureLoop, settings );
+}
 
 bool QgsRuleBasedLabelProvider::prepare( const QgsRenderContext& context, QStringList& attributeNames )
 {
@@ -213,19 +216,20 @@ QDomElement QgsRuleBasedLabeling::Rule::save( QDomDocument& doc ) const
   return ruleElem;
 }
 
-void QgsRuleBasedLabeling::Rule::createSubProviders( QgsVectorLayer* layer, QgsRuleBasedLabeling::RuleToProviderMap& subProviders )
+void QgsRuleBasedLabeling::Rule::createSubProviders( QgsVectorLayer* layer, QgsRuleBasedLabeling::RuleToProviderMap& subProviders, QgsRuleBasedLabelProvider *provider )
 {
   if ( mSettings )
   {
     // add provider!
-    QgsVectorLayerLabelProvider* p = new QgsVectorLayerLabelProvider( layer, false, mSettings );
+    QgsVectorLayerLabelProvider *p = provider->createProvider( layer, false, mSettings );
+    delete subProviders.value( this, nullptr );
     subProviders[this] = p;
   }
 
   // call recursively
   Q_FOREACH ( Rule* rule, mChildren )
   {
-    rule->createSubProviders( layer, subProviders );
+    rule->createSubProviders( layer, subProviders, provider );
   }
 }
 
@@ -262,6 +266,8 @@ QgsRuleBasedLabeling::Rule::RegisterResult QgsRuleBasedLabeling::Rule::registerF
 
   bool registered = false;
 
+  Q_ASSERT( !mSettings == subProviders.contains( this ) );
+
   // do we have active subprovider for the rule?
   if ( subProviders.contains( this ) && mIsActive )
   {

src/core/qgsrulebasedlabeling.h

@@ -19,6 +19,7 @@
 #include <QMap>
 
 #include "qgsvectorlayerlabeling.h"
+#include "qgsvectorlayerlabelprovider.h"
 
 class QDomDocument;
 class QDomElement;
@@ -28,6 +29,7 @@ class QgsFeature;
 class QgsPalLayerSettings;
 class QgsRenderContext;
 class QgsGeometry;
+class QgsRuleBasedLabelProvider;
 
 /**
  * @class QgsRuleBasedLabeling
@@ -42,7 +44,6 @@ class CORE_EXPORT QgsRuleBasedLabeling : public QgsAbstractVectorLayerLabeling
     typedef QList<Rule*> RuleList;
     typedef QMap<Rule*, QgsVectorLayerLabelProvider*> RuleToProviderMap;
 
-
     /**
      * @class QgsRuleBasedLabeling::Rule
      * @note not available in Python bindings
@@ -214,7 +215,7 @@ class CORE_EXPORT QgsRuleBasedLabeling : public QgsAbstractVectorLayerLabeling
         // evaluation
 
         //! add providers
-        void createSubProviders( QgsVectorLayer* layer, RuleToProviderMap& subProviders );
+        void createSubProviders( QgsVectorLayer* layer, RuleToProviderMap& subProviders, QgsRuleBasedLabelProvider *provider );
 
         //! call prepare() on sub-providers and populate attributeNames
         void prepare( const QgsRenderContext& context, QStringList& attributeNames, RuleToProviderMap& subProviders );
@@ -285,15 +286,13 @@ class CORE_EXPORT QgsRuleBasedLabeling : public QgsAbstractVectorLayerLabeling
 
     virtual QString type() const override;
     virtual QDomElement save( QDomDocument& doc ) const override;
-    virtual QgsVectorLayerLabelProvider* provider( QgsVectorLayer* layer ) const override;
+    virtual QgsVectorLayerLabelProvider *provider( QgsVectorLayer* layer ) const override;
 
   protected:
     Rule* mRootRule;
 };
 
 
-#include "qgsvectorlayerlabelprovider.h"
-
 /**
  * @class QgsRuleBasedLabelProvider
  * @note not available in Python bindings
@@ -312,6 +311,7 @@ class CORE_EXPORT QgsRuleBasedLabelProvider : public QgsVectorLayerLabelProvider
     virtual void registerFeature( QgsFeature& feature, QgsRenderContext& context, QgsGeometry* obstacleGeometry = nullptr ) override;
 
     // new methods
+    virtual QgsVectorLayerLabelProvider *createProvider( QgsVectorLayer *layer, bool withFeatureLoop, const QgsPalLayerSettings *settings );
 
     virtual QList<QgsAbstractLabelProvider*> subProviders() override;
 

src/core/qgsvectorlayerlabelprovider.cpp

@@ -316,7 +316,7 @@ QList<QgsLabelFeature*> QgsVectorLayerLabelProvider::labelFeatures( QgsRenderCon
 void QgsVectorLayerLabelProvider::registerFeature( QgsFeature& feature, QgsRenderContext& context, QgsGeometry* obstacleGeometry )
 {
   QgsLabelFeature* label = nullptr;
-  mSettings.registerFeature( feature, context, QString(), &label, obstacleGeometry );
+  mSettings.registerFeature( feature, context, &label, obstacleGeometry );
   if ( label )
     mLabels << label;
 }

src/core/qgsvectorlayerlabelprovider.h

@@ -116,5 +116,4 @@ class CORE_EXPORT QgsVectorLayerLabelProvider : public QgsAbstractLabelProvider
     QList<QgsLabelFeature*> mLabels;
 };
 
-
 #endif // QGSVECTORLAYERLABELPROVIDER_H

tests/src/core/testqgslabelingenginev2.cpp

@@ -259,7 +259,7 @@ void TestQgsLabelingEngineV2::testRuleBased()
 
   delete rl2;
 
-  /*
+#if 0
   QPainter p( &img );
   QgsRenderContext context = QgsRenderContext::fromMapSettings( mapSettings );
   context.setPainter( &p );
@@ -267,7 +267,8 @@ void TestQgsLabelingEngineV2::testRuleBased()
   QgsLabelingEngineV2 engine;
   engine.setMapSettings( mapSettings );
   engine.addProvider( new QgsRuleBasedLabelProvider( , vl ) );
-  engine.run( context );*/
+  engine.run( context );
+#endif
 }
 
 void TestQgsLabelingEngineV2::zOrder()