Add return type QgsRenderOptions to QgsRendererV2::startRender

This allows to specify additional filter constraints for the feature request to
be specified.

.gitignore

@@ -1,4 +1,5 @@
 *.*~
+*.autosave
 *.aux
 *.diff
 *.log*

python/core/symbology-ng/qgscategorizedsymbolrendererv2.sip

@@ -49,7 +49,7 @@ class QgsCategorizedSymbolRendererV2 : QgsFeatureRendererV2
 
     virtual QgsSymbolV2* originalSymbolForFeature( QgsFeature& feature );
 
-    virtual void startRender( QgsRenderContext& context, const QgsFields& fields );
+    virtual QgsRenderOptions startRender( QgsRenderContext& context, const QgsFields& fields );
 
     virtual void stopRender( QgsRenderContext& context );
 

python/core/symbology-ng/qgsgraduatedsymbolrendererv2.sip

@@ -91,7 +91,7 @@ class QgsGraduatedSymbolRendererV2 : QgsFeatureRendererV2
 
     virtual QgsSymbolV2* originalSymbolForFeature( QgsFeature& feature );
 
-    virtual void startRender( QgsRenderContext& context, const QgsFields& fields );
+    virtual QgsRenderOptions startRender( QgsRenderContext& context, const QgsFields& fields );
 
     virtual void stopRender( QgsRenderContext& context );
 

python/core/symbology-ng/qgsheatmaprenderer.sip

@@ -10,7 +10,7 @@ class QgsHeatmapRenderer : QgsFeatureRendererV2
 
     //reimplemented methods
     virtual QgsFeatureRendererV2* clone() const /Factory/;
-    virtual void startRender( QgsRenderContext& context, const QgsFields& fields );
+    virtual QgsRenderOptions startRender( QgsRenderContext& context, const QgsFields& fields );
     virtual bool renderFeature( QgsFeature& feature, QgsRenderContext& context, int layer = -1, bool selected = false, bool drawVertexMarker = false );
     virtual void stopRender( QgsRenderContext& context );
     virtual QgsSymbolV2* symbolForFeature( QgsFeature& feature );

python/core/symbology-ng/qgsinvertedpolygonrenderer.sip

@@ -14,7 +14,7 @@ class QgsInvertedPolygonRenderer : QgsFeatureRendererV2
     /** Used to clone this feature renderer.*/
     virtual QgsFeatureRendererV2* clone() const /Factory/;
 
-    virtual void startRender( QgsRenderContext& context, const QgsFields& fields );
+    virtual QgsRenderOptions startRender( QgsRenderContext& context, const QgsFields& fields );
 
     /** Renders a given feature.
      * This will here collect features. The actual rendering will be postponed to stopRender()

python/core/symbology-ng/qgspointdisplacementrenderer.sip

@@ -16,7 +16,7 @@ class QgsPointDisplacementRenderer : QgsFeatureRendererV2
 
     QgsSymbolV2* symbolForFeature( QgsFeature& feature );
 
-    void startRender( QgsRenderContext& context, const QgsFields& fields );
+    QgsRenderOptions startRender( QgsRenderContext& context, const QgsFields& fields );
 
     void stopRender( QgsRenderContext& context );
 

python/core/symbology-ng/qgsrendererv2.sip

@@ -17,6 +17,16 @@ class QgsSymbolV2LevelItem
     int layer();
 };
 
+class QgsRenderOptions
+{
+%TypeHeaderCode
+#include <qgsrendererv2.h>
+%End
+  public:
+    void setWhereClause( const QString& whereClause );
+    QString whereClause();
+};
+
 // every level has list of items: symbol + symbol layer num
 // typedef QList< QgsSymbolV2LevelItem > QgsSymbolV2Level;
 
@@ -74,7 +84,7 @@ class QgsFeatureRendererV2
      */
     virtual QgsSymbolV2* originalSymbolForFeature( QgsFeature& feature );
 
-    virtual void startRender( QgsRenderContext& context, const QgsFields& fields ) = 0;
+    virtual QgsRenderOptions startRender( QgsRenderContext& context, const QgsFields& fields ) = 0;
 
     //! @deprecated since 2.4 - not using QgsVectorLayer directly anymore
     virtual void startRender( QgsRenderContext& context, const QgsVectorLayer *vlayer ) /Deprecated/;

python/core/symbology-ng/qgsrulebasedrendererv2.sip

@@ -173,7 +173,7 @@ class QgsRuleBasedRendererV2 : QgsFeatureRendererV2
 
     virtual bool renderFeature( QgsFeature& feature, QgsRenderContext& context, int layer = -1, bool selected = false, bool drawVertexMarker = false );
 
-    virtual void startRender( QgsRenderContext& context, const QgsFields& fields );
+    virtual QgsRenderOptions startRender( QgsRenderContext& context, const QgsFields& fields );
 
     virtual void stopRender( QgsRenderContext& context );
 

python/core/symbology-ng/qgssinglesymbolrendererv2.sip

@@ -13,7 +13,7 @@ class QgsSingleSymbolRendererV2 : QgsFeatureRendererV2
 
     virtual QgsSymbolV2* originalSymbolForFeature( QgsFeature& feature );
 
-    virtual void startRender( QgsRenderContext& context, const QgsFields& fields );
+    virtual QgsRenderOptions startRender( QgsRenderContext& context, const QgsFields& fields );
 
     virtual void stopRender( QgsRenderContext& context );
 

src/core/symbology-ng/qgscategorizedsymbolrendererv2.cpp

@@ -396,7 +396,7 @@ void QgsCategorizedSymbolRendererV2::sortByLabel( Qt::SortOrder order )
   }
 }
 
-void QgsCategorizedSymbolRendererV2::startRender( QgsRenderContext& context, const QgsFields& fields )
+QgsRenderOptions QgsCategorizedSymbolRendererV2::startRender( QgsRenderContext& context, const QgsFields& fields )
 {
   mCounting = context.rendererScale() == 0.0;
 
@@ -425,6 +425,7 @@ void QgsCategorizedSymbolRendererV2::startRender( QgsRenderContext& context, con
       mTempSymbols[ it->symbol()] = tempSymbol;
     }
   }
+  return QgsRenderOptions();
 }
 
 void QgsCategorizedSymbolRendererV2::stopRender( QgsRenderContext& context )

src/core/symbology-ng/qgscategorizedsymbolrendererv2.h

@@ -79,7 +79,7 @@ class CORE_EXPORT QgsCategorizedSymbolRendererV2 : public QgsFeatureRendererV2
 
     virtual QgsSymbolV2* originalSymbolForFeature( QgsFeature& feature ) override;
 
-    virtual void startRender( QgsRenderContext& context, const QgsFields& fields ) override;
+    virtual QgsRenderOptions startRender( QgsRenderContext& context, const QgsFields& fields ) override;
 
     virtual void stopRender( QgsRenderContext& context ) override;
 

src/core/symbology-ng/qgsgraduatedsymbolrendererv2.cpp

@@ -369,7 +369,7 @@ QgsSymbolV2* QgsGraduatedSymbolRendererV2::originalSymbolForFeature( QgsFeature&
   return symbolForValue( value.toDouble() );
 }
 
-void QgsGraduatedSymbolRendererV2::startRender( QgsRenderContext& context, const QgsFields& fields )
+QgsRenderOptions QgsGraduatedSymbolRendererV2::startRender( QgsRenderContext& context, const QgsFields& fields )
 {
   mCounting = context.rendererScale() == 0.0;
 
@@ -399,6 +399,7 @@ void QgsGraduatedSymbolRendererV2::startRender( QgsRenderContext& context, const
       mTempSymbols[ it->symbol()] = tempSymbol;
     }
   }
+  return QgsRenderOptions();
 }
 
 void QgsGraduatedSymbolRendererV2::stopRender( QgsRenderContext& context )

src/core/symbology-ng/qgsgraduatedsymbolrendererv2.h

@@ -123,7 +123,7 @@ class CORE_EXPORT QgsGraduatedSymbolRendererV2 : public QgsFeatureRendererV2
 
     virtual QgsSymbolV2* originalSymbolForFeature( QgsFeature& feature ) override;
 
-    virtual void startRender( QgsRenderContext& context, const QgsFields& fields ) override;
+    virtual QgsRenderOptions startRender( QgsRenderContext& context, const QgsFields& fields ) override;
 
     virtual void stopRender( QgsRenderContext& context ) override;
 

src/core/symbology-ng/qgsheatmaprenderer.cpp

@@ -63,12 +63,12 @@ void QgsHeatmapRenderer::initializeValues( QgsRenderContext& context )
   mRadiusSquared = mRadiusPixels * mRadiusPixels;
 }
 
-void QgsHeatmapRenderer::startRender( QgsRenderContext& context, const QgsFields& fields )
+QgsRenderOptions QgsHeatmapRenderer::startRender( QgsRenderContext& context, const QgsFields& fields )
 {
   Q_UNUSED( fields );
   if ( !context.painter() )
   {
-    return;
+    return QgsRenderOptions();
   }
 
   // find out classification attribute index from name
@@ -80,6 +80,7 @@ void QgsHeatmapRenderer::startRender( QgsRenderContext& context, const QgsFields
   }
 
   initializeValues( context );
+  return QgsRenderOptions();
 }
 
 QgsMultiPoint QgsHeatmapRenderer::convertToMultipoint( const QgsGeometry* geom )

src/core/symbology-ng/qgsheatmaprenderer.h

@@ -39,7 +39,7 @@ class CORE_EXPORT QgsHeatmapRenderer : public QgsFeatureRendererV2
 
     //reimplemented methods
     virtual QgsFeatureRendererV2* clone() const override;
-    virtual void startRender( QgsRenderContext& context, const QgsFields& fields ) override;
+    virtual QgsRenderOptions startRender( QgsRenderContext& context, const QgsFields& fields ) override;
     virtual bool renderFeature( QgsFeature& feature, QgsRenderContext& context, int layer = -1, bool selected = false, bool drawVertexMarker = false ) override;
     virtual void stopRender( QgsRenderContext& context ) override;
     virtual QgsSymbolV2* symbolForFeature( QgsFeature& feature ) override;

src/core/symbology-ng/qgsinvertedpolygonrenderer.cpp

@@ -63,11 +63,11 @@ const QgsFeatureRendererV2* QgsInvertedPolygonRenderer::embeddedRenderer() const
   return mSubRenderer.data();
 }
 
-void QgsInvertedPolygonRenderer::startRender( QgsRenderContext& context, const QgsFields& fields )
+QgsRenderOptions QgsInvertedPolygonRenderer::startRender( QgsRenderContext& context, const QgsFields& fields )
 {
   if ( !mSubRenderer )
   {
-    return;
+    return QgsRenderOptions();
   }
 
   // first call start render on the sub renderer
@@ -85,7 +85,7 @@ void QgsInvertedPolygonRenderer::startRender( QgsRenderContext& context, const Q
 
   if ( !context.painter() )
   {
-    return;
+    return QgsRenderOptions();
   }
 
   // convert viewport to dest CRS
@@ -119,6 +119,8 @@ void QgsInvertedPolygonRenderer::startRender( QgsRenderContext& context, const Q
 
   mExtentPolygon.clear();
   mExtentPolygon.append( exteriorRing );
+
+  return QgsRenderOptions();
 }
 
 bool QgsInvertedPolygonRenderer::renderFeature( QgsFeature& feature, QgsRenderContext& context, int layer, bool selected, bool drawVertexMarker )

src/core/symbology-ng/qgsinvertedpolygonrenderer.h

@@ -50,7 +50,7 @@ class CORE_EXPORT QgsInvertedPolygonRenderer : public QgsFeatureRendererV2
     /** Used to clone this feature renderer.*/
     virtual QgsFeatureRendererV2* clone() const override;
 
-    virtual void startRender( QgsRenderContext& context, const QgsFields& fields ) override;
+    virtual QgsRenderOptions startRender( QgsRenderContext& context, const QgsFields& fields ) override;
 
     /** Renders a given feature.
      * This will here collect features. The actual rendering will be postponed to stopRender()

src/core/symbology-ng/qgspointdisplacementrenderer.cpp

@@ -279,7 +279,7 @@ bool QgsPointDisplacementRenderer::willRenderFeature( QgsFeature& feat )
 }
 
 
-void QgsPointDisplacementRenderer::startRender( QgsRenderContext& context, const QgsFields& fields )
+QgsRenderOptions QgsPointDisplacementRenderer::startRender( QgsRenderContext& context, const QgsFields& fields )
 {
   mRenderer->startRender( context, fields );
 
@@ -310,6 +310,7 @@ void QgsPointDisplacementRenderer::startRender( QgsRenderContext& context, const
   {
     mCenterSymbol->startRender( context, &fields );
   }
+  return QgsRenderOptions();
 }
 
 void QgsPointDisplacementRenderer::stopRender( QgsRenderContext& context )

src/core/symbology-ng/qgspointdisplacementrenderer.h

@@ -58,7 +58,7 @@ class CORE_EXPORT QgsPointDisplacementRenderer: public QgsFeatureRendererV2
     /** Proxy that will call this method on the embedded renderer. */
     virtual bool willRenderFeature( QgsFeature& feat ) override;
 
-    void startRender( QgsRenderContext& context, const QgsFields& fields ) override;
+    QgsRenderOptions startRender( QgsRenderContext& context, const QgsFields& fields ) override;
 
     void stopRender( QgsRenderContext& context ) override;
 

src/core/symbology-ng/qgsrendererv2.h

@@ -61,6 +61,15 @@ class CORE_EXPORT QgsSymbolV2LevelItem
     int mLayer;
 };
 
+class CORE_EXPORT QgsRenderOptions
+{
+  public:
+    void setWhereClause( const QString& whereClause ) { mWhereClause = whereClause; }
+    QString whereClause() { return mWhereClause; }
+  private:
+    QString mWhereClause;
+};
+
 // every level has list of items: symbol + symbol layer num
 typedef QList< QgsSymbolV2LevelItem > QgsSymbolV2Level;
 
@@ -95,7 +104,14 @@ class CORE_EXPORT QgsFeatureRendererV2
      */
     virtual QgsSymbolV2* originalSymbolForFeature( QgsFeature& feature ) { return symbolForFeature( feature ); }
 
-    virtual void startRender( QgsRenderContext& context, const QgsFields& fields ) = 0;
+    /**
+     * Needs to be called when a new render cycle is started
+     *
+     * @param context  Additional information passed to the renderer about the job which will be rendered
+     * @param fields   The fields available for rendering
+     * @return         Information passed back from the renderer that can e.g. be used to reduce the amount of requested features
+     */
+    virtual QgsRenderOptions startRender( QgsRenderContext& context, const QgsFields& fields ) = 0;
 
     //! @deprecated since 2.4 - not using QgsVectorLayer directly anymore
     Q_DECL_DEPRECATED virtual void startRender( QgsRenderContext& context, const QgsVectorLayer* vlayer );

src/core/symbology-ng/qgsrulebasedrendererv2.cpp

@@ -779,7 +779,7 @@ bool QgsRuleBasedRendererV2::renderFeature( QgsFeature& feature,
 }
 
 
-void QgsRuleBasedRendererV2::startRender( QgsRenderContext& context, const QgsFields& fields )
+QgsRenderOptions QgsRuleBasedRendererV2::startRender( QgsRenderContext& context, const QgsFields& fields )
 {
   // prepare active children
   mRootRule->startRender( context, fields );
@@ -800,6 +800,7 @@ void QgsRuleBasedRendererV2::startRender( QgsRenderContext& context, const QgsFi
   }
 
   mRootRule->setNormZLevels( zLevelsToNormLevels );
+  return QgsRenderOptions();
 }
 
 void QgsRuleBasedRendererV2::stopRender( QgsRenderContext& context )

src/core/symbology-ng/qgsrulebasedrendererv2.h

@@ -220,7 +220,7 @@ class CORE_EXPORT QgsRuleBasedRendererV2 : public QgsFeatureRendererV2
 
     virtual bool renderFeature( QgsFeature& feature, QgsRenderContext& context, int layer = -1, bool selected = false, bool drawVertexMarker = false ) override;
 
-    virtual void startRender( QgsRenderContext& context, const QgsFields& fields ) override;
+    virtual QgsRenderOptions startRender( QgsRenderContext& context, const QgsFields& fields ) override;
 
     virtual void stopRender( QgsRenderContext& context ) override;
 

src/core/symbology-ng/qgssinglesymbolrendererv2.cpp

@@ -79,9 +79,10 @@ QgsSymbolV2* QgsSingleSymbolRendererV2::originalSymbolForFeature( QgsFeature& fe
   return mSymbol.data();
 }
 
-void QgsSingleSymbolRendererV2::startRender( QgsRenderContext& context, const QgsFields& fields )
+QgsRenderOptions QgsSingleSymbolRendererV2::startRender( QgsRenderContext& context, const QgsFields& fields )
 {
-  if ( !mSymbol.data() ) return;
+  if ( !mSymbol.data() )
+    return QgsRenderOptions();
 
   mSymbol->startRender( context, &fields );
 
@@ -112,6 +113,8 @@ void QgsSingleSymbolRendererV2::startRender( QgsRenderContext& context, const Qg
       mOrigSize = 0;
     }
   }
+
+  return QgsRenderOptions();
 }
 
 void QgsSingleSymbolRendererV2::stopRender( QgsRenderContext& context )

src/core/symbology-ng/qgssinglesymbolrendererv2.h

@@ -33,7 +33,7 @@ class CORE_EXPORT QgsSingleSymbolRendererV2 : public QgsFeatureRendererV2
 
     virtual QgsSymbolV2* originalSymbolForFeature( QgsFeature& feature ) override;
 
-    virtual void startRender( QgsRenderContext& context, const QgsFields& fields ) override;
+    virtual QgsRenderOptions startRender( QgsRenderContext& context, const QgsFields& fields ) override;
 
     virtual void stopRender( QgsRenderContext& context ) override;