m-kuhn · Jun 7, 2016 · wonder-sk · Jun 8, 2016
diff --git a/src/core/qgsmaprendererjob.cpp b/src/core/qgsmaprendererjob.cpp
diff --git a/src/core/qgsmaprendererjob.h b/src/core/qgsmaprendererjob.h
@@ -120,9 +120,22 @@ public slots:
 
 #include <QtConcurrentRun>
 #include <QFutureWatcher>
+#include <QPainter>
 
+class QgsMapLayerRenderer;
 class QgsPalLabeling;
 
+
+
+struct LayerRenderJob
+{
+  QgsRenderContext context;
+  QImage* img; // may be null if it is not necessary to draw to separate image (e.g. sequential rendering)
+  QgsMapLayerRenderer* renderer; // must be deleted
+  QPainter::CompositionMode blendMode;
+};
+
+
 /** job implementation that renders everything sequentially using a custom painter.
  *  The returned image is always invalid (because there is none available).
  */
@@ -146,12 +159,18 @@ protected slots:
 
   void doRender();
 
+  bool needTemporaryImage( QgsMapLayer* ml );
+
 private:
   QPainter* mPainter;
   QFuture<void> mFuture;
   QFutureWatcher<void> mFutureWatcher;
-  QgsRenderContext mRenderContext;
+  QgsRenderContext mRenderContext;  // used just for labeling!
   QgsPalLabeling* mLabelingEngine;
+
+  typedef QList<LayerRenderJob> LayerRenderJobs;
+
+  LayerRenderJobs mLayerJobs;
 };
 
 

diff --git a/src/core/qgspallabeling.cpp b/src/core/qgspallabeling.cpp
@@ -1499,10 +1499,8 @@ void QgsPalLayerSettings::calculateLabelSize( const QFontMetricsF* fm, QString t
   labelY = qAbs( ptSize.y() - ptZero.y() );
 }
 
-void QgsPalLayerSettings::registerFeature( QgsVectorLayer* layer,  QgsFeature& f, const QgsRenderContext& context )
+void QgsPalLayerSettings::registerFeature( QgsFeature& f, const QgsRenderContext& context )
 {
-  Q_UNUSED( layer );
-
   QVariant exprVal; // value() is repeatedly nulled on data defined evaluation and replaced when successful
   mCurFeat = &f;
 //  mCurFields = &layer->pendingFields();
@@ -3351,7 +3349,7 @@ int QgsPalLabeling::addDiagramLayer( QgsVectorLayer* layer, QgsDiagramLayerSetti
 void QgsPalLabeling::registerFeature( QgsVectorLayer* layer, QgsFeature& f, const QgsRenderContext& context )
 {
   QgsPalLayerSettings& lyr = mActiveLayers[layer];
-  lyr.registerFeature( layer, f, context );
+  lyr.registerFeature( f, context );
 }
 
 void QgsPalLabeling::registerDiagramFeature( QgsVectorLayer* layer, QgsFeature& feat, const QgsRenderContext& context )

diff --git a/src/core/qgspallabeling.h b/src/core/qgspallabeling.h
@@ -412,7 +412,7 @@ class CORE_EXPORT QgsPalLayerSettings
     void calculateLabelSize( const QFontMetricsF* fm, QString text, double& labelX, double& labelY, QgsFeature* f = 0 );
 
     // implementation of register feature hook
-    void registerFeature( QgsVectorLayer* layer, QgsFeature& f, const QgsRenderContext& context );
+    void registerFeature( QgsFeature& f, const QgsRenderContext& context );
 
     void readFromLayer( QgsVectorLayer* layer );
     void writeToLayer( QgsVectorLayer* layer );

diff --git a/src/core/qgsvectorfilewriter.cpp b/src/core/qgsvectorfilewriter.cpp
@@ -1527,7 +1527,7 @@ void QgsVectorFileWriter::startRender( QgsVectorLayer* vl ) const
   }
 
   QgsRenderContext ctx = renderContext();
-  renderer->startRender( ctx, vl );
+  renderer->startRender( ctx, vl->pendingFields() );
 }
 
 void QgsVectorFileWriter::stopRender( QgsVectorLayer* vl ) const

diff --git a/src/core/qgsvectorlayer.cpp b/src/core/qgsvectorlayer.cpp
diff --git a/src/core/qgsvectorlayer.h b/src/core/qgsvectorlayer.h
@@ -726,16 +726,6 @@ class CORE_EXPORT QgsVectorLayer : public QgsMapLayer
      */
     void setRendererV2( QgsFeatureRendererV2* r );
 
-    /** Draw layer with renderer V2. QgsFeatureRenderer::startRender() needs to be called before using this method
-     * @note added in 1.4
-     */
-    void drawRendererV2( QgsFeatureIterator &fit, QgsRenderContext& rendererContext, bool labeling );
-
-    /** Draw layer with renderer V2 using symbol levels. QgsFeatureRenderer::startRender() needs to be called before using this method
-     * @note added in 1.4
-     */
-    void drawRendererV2Levels( QgsFeatureIterator &fit, QgsRenderContext& rendererContext, bool labeling );
-
     /** Returns point, line or polygon */
     QGis::GeometryType geometryType() const;
 
@@ -1027,6 +1017,11 @@ class CORE_EXPORT QgsVectorLayer : public QgsMapLayer
       @note added in version 1.6*/
     virtual void reload();
 
+    /** Return new instance of QgsMapLayerRenderer that will be used for rendering of given context
+     * @note added in 2.1
+     */
+    virtual QgsMapLayerRenderer* createMapRenderer( QgsRenderContext& rendererContext );
+
     /** Draws the layer
      *  @return false if an error occurred during drawing
      */
@@ -1546,24 +1541,9 @@ class CORE_EXPORT QgsVectorLayer : public QgsMapLayer
                          QMultiMap<double, QgsSnappingResult>& snappingResults,
                          QgsSnapper::SnappingType snap_to ) const;
 
-    /**Reads vertex marker type from settings*/
-    static QgsVectorLayer::VertexMarkerType currentVertexMarkerType();
-
-    /**Reads vertex marker size from settings*/
-    static int currentVertexMarkerSize();
-
     /** Add joined attributes to a feature */
     //void addJoinedAttributes( QgsFeature& f, bool all = false );
 
-    /** Stop version 2 renderer and selected renderer (if required) */
-    void stopRendererV2( QgsRenderContext& rendererContext, QgsSingleSymbolRendererV2* selRenderer );
-
-    /**Registers label and diagram layer
-      @param rendererContext render context
-      @param attributes attributes needed for labeling and diagrams will be added to the list
-      @param labeling out: true if there will be labeling (ng) for this layer*/
-    void prepareLabelingAndDiagrams( QgsRenderContext& rendererContext, QgsAttributeList& attributes, bool& labeling );
-
   private:                       // Private attributes
 
     /** Pointer to data provider derived from the abastract base class QgsDataProvider */

diff --git a/src/core/qgsvectorlayerrenderer.cpp b/src/core/qgsvectorlayerrenderer.cpp
diff --git a/src/core/qgsvectorlayerrenderer.h b/src/core/qgsvectorlayerrenderer.h
@@ -0,0 +1,90 @@
+#ifndef QGSVECTORLAYERRENDERER_H
+#define QGSVECTORLAYERRENDERER_H
+
+class QgsFeatureRendererV2;
+class QgsRenderContext;
+class QgsVectorLayer;
+
+class QgsDiagramRendererV2;
+class QgsDiagramLayerSettings;
+
+class QgsGeometryCache;
+class QgsFeatureIterator;
+class QgsSingleSymbolRendererV2;
+
+#include <QList>
+#include <QPainter>
+
+typedef QList<int> QgsAttributeList;
+
+#include "qgis.h"
+#include "qgsfield.h"  // QgsFields
+#include "qgsfeature.h"  // QgsFeatureIds
+#include "qgsfeatureiterator.h"
+
+#include "qgsmaplayerrenderer.h"
+
+class QgsVectorLayerRenderer : public QgsMapLayerRenderer
+{
+public:
+  QgsVectorLayerRenderer( QgsVectorLayer* layer, QgsRenderContext& context );
+  ~QgsVectorLayerRenderer();
+
+  virtual bool render();
+
+private:
+
+  /**Registers label and diagram layer
+    @param attributes attributes needed for labeling and diagrams will be added to the list
+   */
+  void prepareLabelingAndDiagrams( QStringList& attributeNames );
+
+  /** Draw layer with renderer V2. QgsFeatureRenderer::startRender() needs to be called before using this method
+   */
+  void drawRendererV2();
+
+  /** Draw layer with renderer V2 using symbol levels. QgsFeatureRenderer::startRender() needs to be called before using this method
+   */
+  void drawRendererV2Levels();
+
+  /** Stop version 2 renderer and selected renderer (if required) */
+  void stopRendererV2( QgsSingleSymbolRendererV2* selRenderer );
+
+
+protected:
+
+  QgsRenderContext& mContext;
+
+  QgsFields mFields;
+
+  QString mLayerID;
+
+  QgsFeatureIds mSelectedFeatureIds;
+
+  QgsFeatureIterator mFit;
+
+  QgsFeatureRendererV2 *mRendererV2;
+
+  //diagram rendering object. 0 if diagram drawing is disabled
+  QgsDiagramRendererV2* mDiagramRenderer;
+
+  //stores infos about diagram placement (placement type, priority, position distance)
+  QgsDiagramLayerSettings* mDiagramLayerSettings;
+
+  bool mCacheFeatures;
+  QgsGeometryCache* mCache;
+
+  bool mDrawVertexMarkers;
+  bool mVertexMarkerOnlyForSelection;
+  int mVertexMarkerStyle, mVertexMarkerSize;
+
+  QGis::GeometryType mGeometryType;
+
+  bool mLabeling;
+
+  int mLayerTransparency;
+  QPainter::CompositionMode mFeatureBlendMode;
+};
+
+
+#endif // QGSVECTORLAYERRENDERER_H
diff --git a/src/core/symbology-ng/qgscategorizedsymbolrendererv2.cpp b/src/core/symbology-ng/qgscategorizedsymbolrendererv2.cpp
@@ -358,33 +358,33 @@ void QgsCategorizedSymbolRendererV2::sortByLabel( Qt::SortOrder order )
   }
 }
 
-void QgsCategorizedSymbolRendererV2::startRender( QgsRenderContext& context, const QgsVectorLayer *vlayer )
+void QgsCategorizedSymbolRendererV2::startRender( QgsRenderContext& context, const QgsFields& fields )
 {
   // make sure that the hash table is up to date
   rebuildHash();
 
   // find out classification attribute index from name
-  mAttrNum = vlayer ? vlayer->fieldNameIndex( mAttrName ) : -1;
+  mAttrNum = fields.fieldNameIndex( mAttrName );
   if ( mAttrNum == -1 )
   {
     mExpression = new QgsExpression( mAttrName );
-    mExpression->prepare( vlayer->pendingFields() );
+    mExpression->prepare( fields );
   }
 
-  mRotationFieldIdx  = ( mRotationField.isEmpty()  ? -1 : vlayer->fieldNameIndex( mRotationField ) );
-  mSizeScaleFieldIdx = ( mSizeScaleField.isEmpty() ? -1 : vlayer->fieldNameIndex( mSizeScaleField ) );
+  mRotationFieldIdx  = ( mRotationField.isEmpty()  ? -1 : fields.fieldNameIndex( mRotationField ) );
+  mSizeScaleFieldIdx = ( mSizeScaleField.isEmpty() ? -1 : fields.fieldNameIndex( mSizeScaleField ) );
 
   QgsCategoryList::iterator it = mCategories.begin();
   for ( ; it != mCategories.end(); ++it )
   {
-    it->symbol()->startRender( context, vlayer );
+    it->symbol()->startRender( context, &fields );
 
     if ( mRotationFieldIdx != -1 || mSizeScaleFieldIdx != -1 )
     {
       QgsSymbolV2* tempSymbol = it->symbol()->clone();
       tempSymbol->setRenderHints(( mRotationFieldIdx != -1 ? QgsSymbolV2::DataDefinedRotation : 0 ) |
                                  ( mSizeScaleFieldIdx != -1 ? QgsSymbolV2::DataDefinedSizeScale : 0 ) );
-      tempSymbol->startRender( context, vlayer );
+      tempSymbol->startRender( context, &fields );
       mTempSymbols[ it->value().toString()] = tempSymbol;
     }
   }

diff --git a/src/core/symbology-ng/qgscategorizedsymbolrendererv2.h b/src/core/symbology-ng/qgscategorizedsymbolrendererv2.h
@@ -71,7 +71,7 @@ class CORE_EXPORT QgsCategorizedSymbolRendererV2 : public QgsFeatureRendererV2
 
     virtual QgsSymbolV2* symbolForFeature( QgsFeature& feature );
 
-    virtual void startRender( QgsRenderContext& context, const QgsVectorLayer *vlayer );
+    virtual void startRender( QgsRenderContext& context, const QgsFields& fields );
 
     virtual void stopRender( QgsRenderContext& context );
 

diff --git a/src/core/symbology-ng/qgsellipsesymbollayerv2.cpp b/src/core/symbology-ng/qgsellipsesymbollayerv2.cpp
@@ -263,7 +263,7 @@ void QgsEllipseSymbolLayerV2::startRender( QgsSymbolV2RenderContext& context )
   mPen.setColor( mOutlineColor );
   mPen.setWidthF( mOutlineWidth * QgsSymbolLayerV2Utils::lineWidthScaleFactor( context.renderContext(), mOutlineWidthUnit ) );
   mBrush.setColor( mFillColor );
-  prepareExpressions( context.layer(), context.renderContext().rendererScale() );
+  prepareExpressions( context.fields(), context.renderContext().rendererScale() );
 }
 
 void QgsEllipseSymbolLayerV2::stopRender( QgsSymbolV2RenderContext & )

diff --git a/src/core/symbology-ng/qgsfillsymbollayerv2.cpp b/src/core/symbology-ng/qgsfillsymbollayerv2.cpp
@@ -152,7 +152,7 @@ void QgsSimpleFillSymbolLayerV2::startRender( QgsSymbolV2RenderContext& context
   mSelPen = QPen( selPenColor );
   mPen.setStyle( mBorderStyle );
   mPen.setWidthF( mBorderWidth * QgsSymbolLayerV2Utils::lineWidthScaleFactor( context.renderContext(), mBorderWidthUnit ) );
-  prepareExpressions( context.layer(), context.renderContext().rendererScale() );
+  prepareExpressions( context.fields(), context.renderContext().rendererScale() );
 }
 
 void QgsSimpleFillSymbolLayerV2::stopRender( QgsSymbolV2RenderContext& context )
@@ -576,7 +576,7 @@ void QgsSVGFillSymbolLayer::startRender( QgsSymbolV2RenderContext& context )
     mOutline->startRender( context.renderContext() );
   }
 
-  prepareExpressions( context.layer(), context.renderContext().rendererScale() );
+  prepareExpressions( context.fields(), context.renderContext().rendererScale() );
 }
 
 void QgsSVGFillSymbolLayer::stopRender( QgsSymbolV2RenderContext& context )
@@ -1096,7 +1096,7 @@ void QgsLinePatternFillSymbolLayer::startRender( QgsSymbolV2RenderContext& conte
     mOutline->startRender( context.renderContext() );
   }
 
-  prepareExpressions( context.layer(), context.renderContext().rendererScale() );
+  prepareExpressions( context.fields(), context.renderContext().rendererScale() );
 }
 
 void QgsLinePatternFillSymbolLayer::stopRender( QgsSymbolV2RenderContext & )
@@ -1467,7 +1467,7 @@ void QgsPointPatternFillSymbolLayer::startRender( QgsSymbolV2RenderContext& cont
   {
     mOutline->startRender( context.renderContext() );
   }
-  prepareExpressions( context.layer(), context.renderContext().rendererScale() );
+  prepareExpressions( context.fields(), context.renderContext().rendererScale() );
 }
 
 void QgsPointPatternFillSymbolLayer::stopRender( QgsSymbolV2RenderContext& context )

diff --git a/src/core/symbology-ng/qgsgraduatedsymbolrendererv2.cpp b/src/core/symbology-ng/qgsgraduatedsymbolrendererv2.cpp
@@ -236,31 +236,31 @@ QgsSymbolV2* QgsGraduatedSymbolRendererV2::symbolForFeature( QgsFeature& feature
   return tempSymbol;
 }
 
-void QgsGraduatedSymbolRendererV2::startRender( QgsRenderContext& context, const QgsVectorLayer *vlayer )
+void QgsGraduatedSymbolRendererV2::startRender( QgsRenderContext& context, const QgsFields& fields )
 {
   // find out classification attribute index from name
-  mAttrNum = vlayer ? vlayer->fieldNameIndex( mAttrName ) : -1;
+  mAttrNum = fields.fieldNameIndex( mAttrName );
 
   if ( mAttrNum == -1 )
   {
     mExpression = new QgsExpression( mAttrName );
-    mExpression->prepare( vlayer->pendingFields() );
+    mExpression->prepare( fields );
   }
 
-  mRotationFieldIdx  = ( mRotationField.isEmpty()  ? -1 : vlayer->fieldNameIndex( mRotationField ) );
-  mSizeScaleFieldIdx = ( mSizeScaleField.isEmpty() ? -1 : vlayer->fieldNameIndex( mSizeScaleField ) );
+  mRotationFieldIdx  = ( mRotationField.isEmpty()  ? -1 : fields.fieldNameIndex( mRotationField ) );
+  mSizeScaleFieldIdx = ( mSizeScaleField.isEmpty() ? -1 : fields.fieldNameIndex( mSizeScaleField ) );
 
   QgsRangeList::iterator it = mRanges.begin();
   for ( ; it != mRanges.end(); ++it )
   {
-    it->symbol()->startRender( context, vlayer );
+    it->symbol()->startRender( context, &fields );
 
     if ( mRotationFieldIdx != -1 || mSizeScaleFieldIdx != -1 )
     {
       QgsSymbolV2* tempSymbol = it->symbol()->clone();
       tempSymbol->setRenderHints(( mRotationFieldIdx != -1 ? QgsSymbolV2::DataDefinedRotation : 0 ) |
                                  ( mSizeScaleFieldIdx != -1 ? QgsSymbolV2::DataDefinedSizeScale : 0 ) );
-      tempSymbol->startRender( context, vlayer );
+      tempSymbol->startRender( context, &fields );
       mTempSymbols[ it->symbol()] = tempSymbol;
     }
   }

diff --git a/src/core/symbology-ng/qgsgraduatedsymbolrendererv2.h b/src/core/symbology-ng/qgsgraduatedsymbolrendererv2.h
@@ -66,7 +66,7 @@ class CORE_EXPORT QgsGraduatedSymbolRendererV2 : public QgsFeatureRendererV2
 
     virtual QgsSymbolV2* symbolForFeature( QgsFeature& feature );
 
-    virtual void startRender( QgsRenderContext& context, const QgsVectorLayer *vlayer );
+    virtual void startRender( QgsRenderContext& context, const QgsFields& fields );
 
     virtual void stopRender( QgsRenderContext& context );
 

diff --git a/src/core/symbology-ng/qgslinesymbollayerv2.cpp b/src/core/symbology-ng/qgslinesymbollayerv2.cpp
@@ -159,7 +159,7 @@ void QgsSimpleLineSymbolLayerV2::startRender( QgsSymbolV2RenderContext& context
   mSelPen.setColor( selColor );
 
   //prepare expressions for data defined properties
-  prepareExpressions( context.layer(), context.renderContext().rendererScale() );
+  prepareExpressions( context.fields(), context.renderContext().rendererScale() );
 }
 
 void QgsSimpleLineSymbolLayerV2::stopRender( QgsSymbolV2RenderContext& context )
@@ -535,10 +535,10 @@ void QgsMarkerLineSymbolLayerV2::startRender( QgsSymbolV2RenderContext& context
     hints |= QgsSymbolV2::DataDefinedSizeScale;
   mMarker->setRenderHints( hints );
 
-  mMarker->startRender( context.renderContext(), context.layer() );
+  mMarker->startRender( context.renderContext(), context.fields() );
 
   //prepare expressions for data defined properties
-  prepareExpressions( context.layer(), context.renderContext().rendererScale() );
+  prepareExpressions( context.fields(), context.renderContext().rendererScale() );
 }
 
 void QgsMarkerLineSymbolLayerV2::stopRender( QgsSymbolV2RenderContext& context )

diff --git a/src/core/symbology-ng/qgsmarkersymbollayerv2.cpp b/src/core/symbology-ng/qgsmarkersymbollayerv2.cpp
@@ -228,7 +228,7 @@ void QgsSimpleMarkerSymbolLayerV2::startRender( QgsSymbolV2RenderContext& contex
     mSelCache = QImage();
   }
 
-  prepareExpressions( context.layer(), context.renderContext().rendererScale() );
+  prepareExpressions( context.fields(), context.renderContext().rendererScale() );
 }
 
 
@@ -868,7 +868,7 @@ void QgsSvgMarkerSymbolLayerV2::startRender( QgsSymbolV2RenderContext& context )
 {
   mOrigSize = mSize; // save in case the size would be data defined
   Q_UNUSED( context );
-  prepareExpressions( context.layer(), context.renderContext().rendererScale() );
+  prepareExpressions( context.fields(), context.renderContext().rendererScale() );
 }
 
 void QgsSvgMarkerSymbolLayerV2::stopRender( QgsSymbolV2RenderContext& context )

diff --git a/src/core/symbology-ng/qgspointdisplacementrenderer.cpp b/src/core/symbology-ng/qgspointdisplacementrenderer.cpp
@@ -199,12 +199,12 @@ QgsSymbolV2* QgsPointDisplacementRenderer::symbolForFeature( QgsFeature& feature
   return 0; //not used any more
 }
 
-void QgsPointDisplacementRenderer::startRender( QgsRenderContext& context, const QgsVectorLayer *vlayer )
+void QgsPointDisplacementRenderer::startRender( QgsRenderContext& context, const QgsFields& fields )
 {
-  mRenderer->startRender( context, vlayer );
+  mRenderer->startRender( context, fields );
 
   //create groups with features that have the same position
-  createDisplacementGroups( const_cast<QgsVectorLayer*>( vlayer ), context.extent() );
+  createDisplacementGroups( 0, context.extent() );
   printInfoDisplacementGroups(); //just for debugging
 
   if ( mLabelAttributeName.isEmpty() )
@@ -213,7 +213,7 @@ void QgsPointDisplacementRenderer::startRender( QgsRenderContext& context, const
   }
   else
   {
-    mLabelIndex = vlayer->fieldNameIndex( mLabelAttributeName );
+    mLabelIndex = fields.fieldNameIndex( mLabelAttributeName );
   }
 
   if ( mMaxLabelScaleDenominator > 0 && context.rendererScale() > mMaxLabelScaleDenominator )
@@ -227,7 +227,7 @@ void QgsPointDisplacementRenderer::startRender( QgsRenderContext& context, const
 
   if ( mCenterSymbol )
   {
-    mCenterSymbol->startRender( context, vlayer );
+    mCenterSymbol->startRender( context, &fields );
   }
 }
 
@@ -341,6 +341,9 @@ QgsLegendSymbolList QgsPointDisplacementRenderer::legendSymbolItems( double scal
 
 void QgsPointDisplacementRenderer::createDisplacementGroups( QgsVectorLayer* vlayer, const QgsRectangle& viewExtent )
 {
+  Q_ASSERT( 0 && "Point Displacement Renderer is currently not working - it is now illegal to interact with QgsVectorLayer"
+            " in any way. The renderer should build groups in the renderFeature() calls and then do all rendering in stopRender()");
+
   if ( !vlayer || ( vlayer->wkbType() != QGis::WKBPoint && vlayer->wkbType() != QGis::WKBPoint25D ) )
   {
     return;

diff --git a/src/core/symbology-ng/qgspointdisplacementrenderer.h b/src/core/symbology-ng/qgspointdisplacementrenderer.h
@@ -43,7 +43,7 @@ class CORE_EXPORT QgsPointDisplacementRenderer: public QgsFeatureRendererV2
 
     QgsSymbolV2* symbolForFeature( QgsFeature& feature );
 
-    void startRender( QgsRenderContext& context, const QgsVectorLayer *vlayer );
+    void startRender( QgsRenderContext& context, const QgsFields& fields );
 
     void stopRender( QgsRenderContext& context );
 

diff --git a/src/core/symbology-ng/qgsrendererv2.cpp b/src/core/symbology-ng/qgsrendererv2.cpp
@@ -211,6 +211,11 @@ QgsFeatureRendererV2* QgsFeatureRendererV2::defaultRenderer( QGis::GeometryType
   return new QgsSingleSymbolRendererV2( QgsSymbolV2::defaultSymbol( geomType ) );
 }
 
+void QgsFeatureRendererV2::startRender( QgsRenderContext& context, const QgsVectorLayer* vlayer )
+{
+  startRender( context, vlayer->pendingFields() );
+}
+
 
 bool QgsFeatureRendererV2::renderFeature( QgsFeature& feature, QgsRenderContext& context, int layer, bool selected, bool drawVertexMarker )
 {

diff --git a/src/core/symbology-ng/qgsrendererv2.h b/src/core/symbology-ng/qgsrendererv2.h
@@ -29,6 +29,7 @@
 class QgsSymbolV2;
 class QgsRenderContext;
 class QgsFeature;
+class QgsFields;
 class QgsVectorLayer;
 
 typedef QMap<QString, QString> QgsStringMap;
@@ -81,7 +82,10 @@ class CORE_EXPORT QgsFeatureRendererV2
      */
     virtual QgsSymbolV2* symbolForFeature( QgsFeature& feature ) = 0;
 
-    virtual void startRender( QgsRenderContext& context, const QgsVectorLayer *vlayer ) = 0;
+    virtual void startRender( QgsRenderContext& context, const QgsFields& fields ) = 0;
+
+    //! @deprecated since 2.1 - not using QgsVectorLayer directly anymore
+    Q_DECL_DEPRECATED virtual void startRender( QgsRenderContext& context, const QgsVectorLayer* vlayer );
 
     virtual void stopRender( QgsRenderContext& context ) = 0;
 

diff --git a/src/core/symbology-ng/qgsrulebasedrendererv2.cpp b/src/core/symbology-ng/qgsrulebasedrendererv2.cpp
@@ -345,7 +345,7 @@ void QgsRuleBasedRendererV2::Rule::toSld( QDomDocument& doc, QDomElement &elemen
   }
 }
 
-bool QgsRuleBasedRendererV2::Rule::startRender( QgsRenderContext& context, const QgsVectorLayer *vlayer )
+bool QgsRuleBasedRendererV2::Rule::startRender( QgsRenderContext& context, const QgsFields& fields )
 {
   mActiveChildren.clear();
 
@@ -355,16 +355,16 @@ bool QgsRuleBasedRendererV2::Rule::startRender( QgsRenderContext& context, const
 
   // init this rule
   if ( mFilter )
-    mFilter->prepare( vlayer->pendingFields() );
+    mFilter->prepare( fields );
   if ( mSymbol )
-    mSymbol->startRender( context, vlayer );
+    mSymbol->startRender( context, &fields );
 
   // init children
   // build temporary list of active rules (usable with this scale)
   for ( RuleList::iterator it = mChildren.begin(); it != mChildren.end(); ++it )
   {
     Rule* rule = *it;
-    if ( rule->startRender( context, vlayer ) )
+    if ( rule->startRender( context, fields ) )
     {
       // only add those which are active with current scale
       mActiveChildren.append( rule );
@@ -726,10 +726,10 @@ bool QgsRuleBasedRendererV2::renderFeature( QgsFeature& feature,
 }
 
 
-void QgsRuleBasedRendererV2::startRender( QgsRenderContext& context, const QgsVectorLayer *vlayer )
+void QgsRuleBasedRendererV2::startRender( QgsRenderContext& context, const QgsFields& fields )
 {
   // prepare active children
-  mRootRule->startRender( context, vlayer );
+  mRootRule->startRender( context, fields );
 
   QSet<int> symbolZLevelsSet = mRootRule->collectZLevels();
   QList<int> symbolZLevels = symbolZLevelsSet.toList();

diff --git a/src/core/symbology-ng/qgsrulebasedrendererv2.h b/src/core/symbology-ng/qgsrulebasedrendererv2.h
@@ -123,7 +123,7 @@ class CORE_EXPORT QgsRuleBasedRendererV2 : public QgsFeatureRendererV2
         QDomElement save( QDomDocument& doc, QgsSymbolV2Map& symbolMap );
 
         //! prepare the rule for rendering and its children (build active children array)
-        bool startRender( QgsRenderContext& context, const QgsVectorLayer *vlayer );
+        bool startRender( QgsRenderContext& context, const QgsFields& fields );
         //! get all used z-levels from this rule and children
         QSet<int> collectZLevels();
         //! assign normalized z-levels [0..N-1] for this rule's symbol for quick access during rendering
@@ -203,7 +203,7 @@ class CORE_EXPORT QgsRuleBasedRendererV2 : public QgsFeatureRendererV2
 
     virtual bool renderFeature( QgsFeature& feature, QgsRenderContext& context, int layer = -1, bool selected = false, bool drawVertexMarker = false );
 
-    virtual void startRender( QgsRenderContext& context, const QgsVectorLayer *vlayer );
+    virtual void startRender( QgsRenderContext& context, const QgsFields& fields );
 
     virtual void stopRender( QgsRenderContext& context );
 

diff --git a/src/core/symbology-ng/qgssinglesymbolrendererv2.cpp b/src/core/symbology-ng/qgssinglesymbolrendererv2.cpp
@@ -80,16 +80,16 @@ QgsSymbolV2* QgsSingleSymbolRendererV2::symbolForFeature( QgsFeature& feature )
   return mTempSymbol;
 }
 
-void QgsSingleSymbolRendererV2::startRender( QgsRenderContext& context, const QgsVectorLayer *vlayer )
+void QgsSingleSymbolRendererV2::startRender( QgsRenderContext& context, const QgsFields& fields )
 {
   if ( !mSymbol )
   {
     return;
   }
-  mRotationFieldIdx  = mRotationField.isEmpty()  ? -1 : vlayer->fieldNameIndex( mRotationField );
-  mSizeScaleFieldIdx = mSizeScaleField.isEmpty() ? -1 : vlayer->fieldNameIndex( mSizeScaleField );
+  mRotationFieldIdx  = mRotationField.isEmpty()  ? -1 : fields.fieldNameIndex( mRotationField );
+  mSizeScaleFieldIdx = mSizeScaleField.isEmpty() ? -1 : fields.fieldNameIndex( mSizeScaleField );
 
-  mSymbol->startRender( context, vlayer );
+  mSymbol->startRender( context, &fields );
 
   if ( mRotationFieldIdx != -1 || mSizeScaleFieldIdx != -1 )
   {
@@ -103,7 +103,7 @@ void QgsSingleSymbolRendererV2::startRender( QgsRenderContext& context, const Qg
       hints |= QgsSymbolV2::DataDefinedSizeScale;
     mTempSymbol->setRenderHints( hints );
 
-    mTempSymbol->startRender( context, vlayer );
+    mTempSymbol->startRender( context, &fields );
 
     if ( mSymbol->type() == QgsSymbolV2::Marker )
     {

diff --git a/src/core/symbology-ng/qgssinglesymbolrendererv2.h b/src/core/symbology-ng/qgssinglesymbolrendererv2.h
@@ -29,7 +29,7 @@ class CORE_EXPORT QgsSingleSymbolRendererV2 : public QgsFeatureRendererV2
 
     virtual QgsSymbolV2* symbolForFeature( QgsFeature& feature );
 
-    virtual void startRender( QgsRenderContext& context, const QgsVectorLayer *vlayer );
+    virtual void startRender( QgsRenderContext& context, const QgsFields& fields );
 
     virtual void stopRender( QgsRenderContext& context );
 

diff --git a/src/core/symbology-ng/qgssymbollayerv2.cpp b/src/core/symbology-ng/qgssymbollayerv2.cpp
@@ -76,20 +76,19 @@ void QgsSymbolLayerV2::removeDataDefinedProperties()
   mDataDefinedProperties.clear();
 }
 
-void QgsSymbolLayerV2::prepareExpressions( const QgsVectorLayer* vl, double scale )
+void QgsSymbolLayerV2::prepareExpressions( const QgsFields* fields, double scale )
 {
-  if ( !vl )
+  if ( !fields )
   {
     return;
   }
 
-  const QgsFields& fields = vl->pendingFields();
   QMap< QString, QgsExpression* >::iterator it = mDataDefinedProperties.begin();
   for ( ; it != mDataDefinedProperties.end(); ++it )
   {
     if ( it.value() )
     {
-      it.value()->prepare( fields );
+      it.value()->prepare( *fields );
       if ( scale > 0 )
       {
         it.value()->setScale( scale );

diff --git a/src/core/symbology-ng/qgssymbollayerv2.h b/src/core/symbology-ng/qgssymbollayerv2.h
@@ -108,7 +108,7 @@ class CORE_EXPORT QgsSymbolLayerV2
     static const bool selectFillBorder = false;  // Fill symbol layer also selects border symbology
     static const bool selectFillStyle = false;   // Fill symbol uses symbol layer style..
 
-    virtual void prepareExpressions( const QgsVectorLayer* vl, double scale = -1 );
+    virtual void prepareExpressions( const QgsFields* fields, double scale = -1 );
     virtual QgsExpression* expression( const QString& property );
     /**Saves data defined properties to string map*/
     void saveDataDefinedProperties( QgsStringMap& stringMap ) const;

diff --git a/src/core/symbology-ng/qgssymbolv2.cpp b/src/core/symbology-ng/qgssymbolv2.cpp
@@ -213,10 +213,9 @@ bool QgsSymbolV2::changeSymbolLayer( int index, QgsSymbolLayerV2* layer )
 }
 
 
-void QgsSymbolV2::startRender( QgsRenderContext& context, const QgsVectorLayer* layer )
+void QgsSymbolV2::startRender( QgsRenderContext& context, const QgsFields* fields )
 {
-  QgsSymbolV2RenderContext symbolContext( context, outputUnit(), mAlpha, false, mRenderHints );
-  symbolContext.setLayer( layer );
+  QgsSymbolV2RenderContext symbolContext( context, outputUnit(), mAlpha, false, mRenderHints, 0, fields );
   for ( QgsSymbolLayerV2List::iterator it = mLayers.begin(); it != mLayers.end(); ++it )
     ( *it )->startRender( symbolContext );
 }
@@ -375,8 +374,8 @@ QSet<QString> QgsSymbolV2::usedAttributes() const
 ////////////////////
 
 
-QgsSymbolV2RenderContext::QgsSymbolV2RenderContext( QgsRenderContext& c, QgsSymbolV2::OutputUnit u, qreal alpha, bool selected, int renderHints, const QgsFeature* f )
-    : mRenderContext( c ), mOutputUnit( u ), mAlpha( alpha ), mSelected( selected ), mRenderHints( renderHints ), mFeature( f ), mLayer( 0 )
+QgsSymbolV2RenderContext::QgsSymbolV2RenderContext( QgsRenderContext& c, QgsSymbolV2::OutputUnit u, qreal alpha, bool selected, int renderHints, const QgsFeature* f, const QgsFields* fields )
+    : mRenderContext( c ), mOutputUnit( u ), mAlpha( alpha ), mSelected( selected ), mRenderHints( renderHints ), mFeature( f ), mFields( fields )
 {
 
 }

diff --git a/src/core/symbology-ng/qgssymbolv2.h b/src/core/symbology-ng/qgssymbolv2.h
@@ -32,6 +32,7 @@ class QDomElement;
 //class
 
 class QgsFeature;
+class QgsFields;
 class QgsSymbolLayerV2;
 class QgsRenderContext;
 class QgsVectorLayer;
@@ -97,7 +98,7 @@ class CORE_EXPORT QgsSymbolV2
     //! delete layer at specified index and set a new one
     bool changeSymbolLayer( int index, QgsSymbolLayerV2* layer );
 
-    void startRender( QgsRenderContext& context, const QgsVectorLayer* layer = 0 );
+    void startRender( QgsRenderContext& context, const QgsFields* fields = 0 );
     void stopRender( QgsRenderContext& context );
 
     void setColor( const QColor& color );
@@ -152,7 +153,7 @@ class CORE_EXPORT QgsSymbolV2
 class CORE_EXPORT QgsSymbolV2RenderContext
 {
   public:
-    QgsSymbolV2RenderContext( QgsRenderContext& c, QgsSymbolV2::OutputUnit u , qreal alpha = 1.0, bool selected = false, int renderHints = 0, const QgsFeature* f = 0 );
+    QgsSymbolV2RenderContext( QgsRenderContext& c, QgsSymbolV2::OutputUnit u , qreal alpha = 1.0, bool selected = false, int renderHints = 0, const QgsFeature* f = 0, const QgsFields* = 0 );
     ~QgsSymbolV2RenderContext();
 
     QgsRenderContext& renderContext() { return mRenderContext; }
@@ -176,10 +177,14 @@ class CORE_EXPORT QgsSymbolV2RenderContext
     void setRenderHints( int hints ) { mRenderHints = hints; }
 
     void setFeature( const QgsFeature* f ) { mFeature = f; }
+    //! Current feature being rendered - may be null
     const QgsFeature* feature() const { return mFeature; }
 
-    void setLayer( const QgsVectorLayer* layer ) { mLayer = layer; }
-    const QgsVectorLayer* layer() const { return mLayer; }
+    //! Fields of the layer. Currently only available in startRender() calls
+    //! to allow symbols with data-defined properties prepare the expressions
+    //! (other times fields() returns null)
+    //! @note added in 2.1
+    const QgsFields* fields() const { return mFields; }
 
     double outputLineWidth( double width ) const;
     double outputPixelSize( double size ) const;
@@ -194,7 +199,7 @@ class CORE_EXPORT QgsSymbolV2RenderContext
     bool mSelected;
     int mRenderHints;
     const QgsFeature* mFeature; //current feature
-    const QgsVectorLayer* mLayer; //current vectorlayer
+    const QgsFields* mFields;
 };
 
 

diff --git a/src/core/symbology-ng/qgsvectorfieldsymbollayer.cpp b/src/core/symbology-ng/qgsvectorfieldsymbollayer.cpp
@@ -150,11 +150,11 @@ void QgsVectorFieldSymbolLayer::startRender( QgsSymbolV2RenderContext& context )
     mLineSymbol->startRender( context.renderContext() );
   }
 
-  const QgsVectorLayer* layer = context.layer();
-  if ( layer )
+  const QgsFields* fields = context.fields();
+  if ( fields )
   {
-    mXIndex = layer->fieldNameIndex( mXAttribute );
-    mYIndex = layer->fieldNameIndex( mYAttribute );
+    mXIndex = fields->fieldNameIndex( mXAttribute );
+    mYIndex = fields->fieldNameIndex( mYAttribute );
   }
   else
   {

diff --git a/src/gui/attributetable/qgsattributetablefiltermodel.cpp b/src/gui/attributetable/qgsattributetablefiltermodel.cpp
@@ -258,7 +258,7 @@ void QgsAttributeTableFilterModel::generateListOfVisibleFeatures()
     filter = renderer && renderer->capabilities() & QgsFeatureRendererV2::Filter;
   }
 
-  renderer->startRender( renderContext, layer() );
+  renderer->startRender( renderContext, layer()->pendingFields() );
 
   QgsFeatureIterator features = masterModel()->layerCache()->getFeatures( QgsFeatureRequest().setFlags( QgsFeatureRequest::NoGeometry ).setFilterRect( rect ) );
 

diff --git a/src/gui/qgsmaptoolidentify.cpp b/src/gui/qgsmaptoolidentify.cpp
@@ -318,7 +318,7 @@ bool QgsMapToolIdentify::identifyVectorLayer( QList<IdentifyResult> *results, Qg
   if ( renderer && renderer->capabilities() & QgsFeatureRendererV2::ScaleDependent )
   {
     // setup scale for scale dependent visibility (rule based)
-    renderer->startRender( context, layer );
+    renderer->startRender( context, layer->pendingFields() );
     filter = renderer->capabilities() & QgsFeatureRendererV2::Filter;
   }
 

diff --git a/src/gui/symbology-ng/qgsrulebasedrendererv2widget.cpp b/src/gui/symbology-ng/qgsrulebasedrendererv2widget.cpp
@@ -458,7 +458,7 @@ void QgsRuleBasedRendererV2Widget::countFeatures()
 
   QgsRenderContext renderContext;
   renderContext.setRendererScale( 0 ); // ignore scale
-  mRenderer->startRender( renderContext, mLayer );
+  mRenderer->startRender( renderContext, mLayer->pendingFields() );
 
   int nFeatures = mLayer->pendingFeatureCount();
   QProgressDialog p( tr( "Calculating feature count." ), tr( "Abort" ), 0, nFeatures );

diff --git a/tests/src/core/testqgsrulebasedrenderer.cpp b/tests/src/core/testqgsrulebasedrenderer.cpp
@@ -84,7 +84,7 @@ class TestQgsRuleBasedRenderer: public QObject
       QVERIFY( r.capabilities() & QgsFeatureRendererV2::MoreSymbolsPerFeature );
 
       QgsRenderContext ctx; // dummy render context
-      r.startRender( ctx, layer );
+      r.startRender( ctx, layer->pendingFields() );
 
       // test willRenderFeature
       QVERIFY( r.willRenderFeature( f1 ) == true );