void QgsVectorLayerDiagramProvider::registerFeature( QgsFeature& feature, QgsRenderContext& context, QgsGeometry* obstacleGeometry )
{
  QgsLabelFeature* label = registerDiagram( feature, context, obstacleGeometry );
  if ( label )
    mFeatures << label;
}
void QgsVectorLayerDiagramProvider::registerFeature( QgsFeature& feature, QgsRenderContext& context )
{
  QgsLabelFeature* label = registerDiagram( feature, context );
  if ( label )
    mFeatures << label;
}