Prepared expression evaluation

qgis · Mar 10, 2019 · bb60f4c · bb60f4c
1 parent dd003da
commit bb60f4c
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Showing 2 changed files with 9 additions and 6 deletions.
diff --git a/src/core/qgspallabeling.cpp b/src/core/qgspallabeling.cpp
@@ -1223,12 +1223,13 @@ void QgsPalLayerSettings::registerFeature( const QgsFeature &f, QgsRenderContext
   QgsFeature feature = f;
   if ( geometryGeneratorEnabled )
   {
-    QgsExpressionContext expContext = context.expressionContext();
-    // TODO: cache and prepare
-    QgsExpression exp( geometryGenerator );
-    exp.prepare( &expContext );
-    expContext.setFeature( feature );
-    QgsGeometry geometry = exp.evaluate( &expContext ).value<QgsGeometry>();
+    if ( !mGeometryGeneratorExpression.isValid() )
+    {
+      mGeometryGeneratorExpression = QgsExpression( geometryGenerator );
+      mGeometryGeneratorExpression.prepare( &context.expressionContext() );
+    }
+    context.expressionContext().setFeature( feature );
+    const QgsGeometry geometry = mGeometryGeneratorExpression.evaluate( &context.expressionContext() ).value<QgsGeometry>();
     feature.setGeometry( geometry );
   }
 

diff --git a/src/core/qgspallabeling.h b/src/core/qgspallabeling.h
@@ -927,6 +927,8 @@ class CORE_EXPORT QgsPalLayerSettings
 
     QgsTextFormat mFormat;
 
+    QgsExpression mGeometryGeneratorExpression;
+
     static const QVector< PredefinedPointPosition > DEFAULT_PLACEMENT_ORDER;
 
     static void initPropertyDefinitions();