Make distance based renderers much faster when filters are present

Author: nyalldawson

python/core/symbology-ng/qgspointdistancerenderer.sip

@@ -68,6 +68,7 @@ class QgsPointDistanceRenderer : QgsFeatureRenderer
     bool legendSymbolItemsCheckable() const;
     bool legendSymbolItemChecked( const QString& key );
     void checkLegendSymbolItem( const QString& key, bool state );
+    virtual QString filter( const QgsFields& fields = QgsFields() );
 
     /** Sets the attribute name for labeling points.
      * @param name attribute name, or empty string to avoid labeling features by the renderer

src/core/symbology-ng/qgspointdistancerenderer.cpp

@@ -185,6 +185,14 @@ void QgsPointDistanceRenderer::checkLegendSymbolItem( const QString& key, bool s
   return mRenderer->checkLegendSymbolItem( key, state );
 }
 
+QString QgsPointDistanceRenderer::filter( const QgsFields& fields )
+{
+  if ( !mRenderer )
+    return QgsFeatureRenderer::filter( fields );
+  else
+    return mRenderer->filter( fields );
+}
+
 QList<QString> QgsPointDistanceRenderer::usedAttributes()
 {
   QList<QString> attributeList;

src/core/symbology-ng/qgspointdistancerenderer.h

@@ -94,6 +94,7 @@ class CORE_EXPORT QgsPointDistanceRenderer: public QgsFeatureRenderer
     bool legendSymbolItemsCheckable() const override;
     bool legendSymbolItemChecked( const QString& key ) override;
     void checkLegendSymbolItem( const QString& key, bool state ) override;
+    virtual QString filter( const QgsFields& fields = QgsFields() ) override;
 
     /** Sets the attribute name for labeling points.
      * @param name attribute name, or empty string to avoid labeling features by the renderer