Add separate bool for controlling whether vector layer labels

are enabled

Instead of clearing the labeling configuration in order to
disable labels, we need a way to disable them without
losing the configuration. Labels are oftern temporarily
switched on/off as an analysis tool, and we don't want the
settings to be lost as a result

Refs #17656

python/core/qgsvectorlayer.sip.in

@@ -659,6 +659,22 @@ Returns whether the layer contains labels which are enabled and should be drawn.
 :return: true if layer contains enabled labels
 
 .. versionadded:: 2.9
+
+.. seealso:: :py:func:`setLabelsEnabled`
+%End
+
+    void setLabelsEnabled( bool enabled );
+%Docstring
+Sets whether labels should be ``enabled`` for the layer.
+
+.. note::
+
+   Labels will only be rendered if labelsEnabled() is true and a labeling
+   object is returned by labeling().
+
+.. seealso:: :py:func:`labelsEnabled`
+
+.. seealso:: :py:func:`labeling`
 %End
 
     bool diagramsEnabled() const;
@@ -1332,7 +1348,13 @@ editing.
 %Docstring
 Access to labeling configuration. May be null if labeling is not used.
 
+.. note::
+
+   Labels will only be rendered if labelsEnabled() returns true.
+
 .. versionadded:: 3.0
+
+.. seealso:: :py:func:`labelsEnabled`
 %End
 
     void setLabeling( QgsAbstractVectorLayerLabeling *labeling /Transfer/ );

src/app/dwg/qgsdwgimportdialog.cpp

@@ -414,6 +414,7 @@ void QgsDwgImportDialog::createGroup( QgsLayerTreeGroup *group, const QString &n
 
     pls.placement = QgsPalLayerSettings::OrderedPositionsAroundPoint;
     l->setLabeling( new QgsVectorLayerSimpleLabeling( pls ) );
+    l->setLabelsEnabled( true );
   }
 
   l = layer( layerGroup, layerFilter, QStringLiteral( "points" ) );

src/app/qgslabelingwidget.cpp

@@ -50,6 +50,7 @@ void QgsLabelingWidget::resetSettings()
   if ( mOldSettings )
   {
     mLayer->setLabeling( mOldSettings.release() );
+    mLayer->setLabelsEnabled( mOldLabelsEnabled );
   }
   setLayer( mLayer );
 }
@@ -75,6 +76,7 @@ void QgsLabelingWidget::setLayer( QgsMapLayer *mapLayer )
   }
   else
     mOldSettings.reset();
+  mOldLabelsEnabled = mLayer->labelsEnabled();
 
   adaptToLayer();
 }
@@ -87,11 +89,11 @@ void QgsLabelingWidget::adaptToLayer()
   whileBlocking( mLabelModeComboBox )->setCurrentIndex( -1 );
 
   // pick the right mode of the layer
-  if ( mLayer->labeling() && mLayer->labeling()->type() == QLatin1String( "rule-based" ) )
+  if ( mLayer->labelsEnabled() && mLayer->labeling()->type() == QLatin1String( "rule-based" ) )
   {
     mLabelModeComboBox->setCurrentIndex( 2 );
   }
-  else if ( mLayer->labeling() && mLayer->labeling()->type() == QLatin1String( "simple" ) )
+  else if ( mLayer->labelsEnabled() && mLayer->labeling()->type() == QLatin1String( "simple" ) )
   {
     QgsPalLayerSettings lyr = mLayer->labeling()->settings();
 
@@ -117,14 +119,16 @@ void QgsLabelingWidget::writeSettingsToLayer()
     const QgsRuleBasedLabeling::Rule *rootRule = qobject_cast<QgsRuleBasedLabelingWidget *>( mWidget )->rootRule();
 
     mLayer->setLabeling( new QgsRuleBasedLabeling( rootRule->clone() ) );
+    mLayer->setLabelsEnabled( true );
   }
   else if ( index == 1 || index == 3 )
   {
     mLayer->setLabeling( new QgsVectorLayerSimpleLabeling( qobject_cast<QgsLabelingGui *>( mWidget )->layerSettings() ) );
+    mLayer->setLabelsEnabled( true );
   }
   else
   {
-    mLayer->setLabeling( nullptr );
+    mLayer->setLabelsEnabled( false );
   }
 }
 

src/app/qgslabelingwidget.h

@@ -73,6 +73,7 @@ class QgsLabelingWidget : public QgsMapLayerConfigWidget, private Ui::QgsLabelin
     QWidget *mWidget = nullptr;
     std::unique_ptr< QgsPalLayerSettings > mSimpleSettings;
     std::unique_ptr< QgsAbstractVectorLayerLabeling > mOldSettings;
+    bool mOldLabelsEnabled = false;
 };
 
 #endif // QGSLABELINGWIDGET_H

src/app/qgsmaptoollabel.cpp

@@ -470,7 +470,7 @@ bool QgsMapToolLabel::currentLabelDataDefinedPosition( double &x, bool &xSuccess
 
 bool QgsMapToolLabel::layerIsRotatable( QgsVectorLayer *vlayer, int &rotationCol ) const
 {
-  if ( !vlayer || !vlayer->isEditable() || !vlayer->labeling() )
+  if ( !vlayer || !vlayer->isEditable() || !vlayer->labelsEnabled() )
   {
     return false;
   }
@@ -591,7 +591,7 @@ bool QgsMapToolLabel::diagramMoveable( QgsVectorLayer *vlayer, int &xCol, int &y
 
 bool QgsMapToolLabel::labelMoveable( QgsVectorLayer *vlayer, int &xCol, int &yCol ) const
 {
-  if ( !vlayer || !vlayer->isEditable() || !vlayer->labeling() )
+  if ( !vlayer || !vlayer->isEditable() || !vlayer->labelsEnabled() )
   {
     return false;
   }
@@ -624,7 +624,7 @@ bool QgsMapToolLabel::layerCanPin( QgsVectorLayer *vlayer, int &xCol, int &yCol
 
 bool QgsMapToolLabel::labelCanShowHide( QgsVectorLayer *vlayer, int &showCol ) const
 {
-  if ( !vlayer || !vlayer->isEditable() || !vlayer->labeling() )
+  if ( !vlayer || !vlayer->isEditable() || !vlayer->labelsEnabled() )
   {
     return false;
   }
@@ -691,7 +691,7 @@ QgsMapToolLabel::LabelDetails::LabelDetails( const QgsLabelPosition &p )
   : pos( p )
 {
   layer = qobject_cast<QgsVectorLayer *>( QgsProject::instance()->mapLayer( pos.layerID ) );
-  if ( layer && layer->labeling() && !p.isDiagram )
+  if ( layer && layer->labelsEnabled() && !p.isDiagram )
   {
     settings = layer->labeling()->settings( pos.providerID );
     valid = true;
@@ -719,8 +719,8 @@ bool QgsMapToolLabel::createAuxiliaryFields( LabelDetails &details, QgsPalIndexe
   QgsVectorLayer *vlayer = details.layer;
   QString providerId = details.pos.providerID;
 
-  if ( !vlayer || !vlayer->labeling() )
-    return newAuxiliaryLayer;
+  if ( !vlayer || !vlayer->labelsEnabled() )
+    return false;
 
   if ( !vlayer->auxiliaryLayer() )
   {

src/core/dxf/qgsdxfexport.cpp

@@ -1009,7 +1009,7 @@ void QgsDxfExport::writeEntities()
       attributes << layerAttr;
     }
 
-    const QgsAbstractVectorLayerLabeling *labeling = vl->labeling();
+    const QgsAbstractVectorLayerLabeling *labeling = vl->labelsEnabled() ? vl->labeling() : nullptr;
     QgsDxfLabelProvider *lp = nullptr;
     QgsDxfRuleBasedLabelProvider *rblp = nullptr;
     if ( const QgsRuleBasedLabeling *rbl = dynamic_cast<const QgsRuleBasedLabeling *>( labeling ) )

src/core/qgsmaprendererjob.cpp

@@ -91,7 +91,7 @@ bool QgsMapRendererJob::prepareLabelCache() const
     QgsVectorLayer *vl = const_cast< QgsVectorLayer * >( qobject_cast<const QgsVectorLayer *>( ml ) );
     if ( vl && QgsPalLabeling::staticWillUseLayer( vl ) )
       labeledLayers << vl;
-    if ( vl && vl->labeling() && vl->labeling()->requiresAdvancedEffects() )
+    if ( vl && vl->labelsEnabled() && vl->labeling()->requiresAdvancedEffects() )
     {
       canCache = false;
       break;

src/core/qgsvectorlayer.cpp

@@ -233,6 +233,8 @@ QgsVectorLayer *QgsVectorLayer::clone() const
   {
     layer->setLabeling( labeling()->clone() );
   }
+  layer->setLabelsEnabled( labelsEnabled() );
+
   layer->setSimplifyMethod( simplifyMethod() );
 
   if ( diagramRenderer() )
@@ -666,7 +668,12 @@ QgsRectangle QgsVectorLayer::boundingBoxOfSelected() const
 
 bool QgsVectorLayer::labelsEnabled() const
 {
-  return static_cast< bool >( mLabeling );
+  return mLabelsEnabled && static_cast< bool >( mLabeling );
+}
+
+void QgsVectorLayer::setLabelsEnabled( bool enabled )
+{
+  mLabelsEnabled = enabled;
 }
 
 bool QgsVectorLayer::diagramsEnabled() const
@@ -1949,6 +1956,11 @@ bool QgsVectorLayer::readStyle( const QDomNode &node, QString &errorMessage, con
     }
     setLabeling( labeling );
 
+    if ( node.toElement().hasAttribute( QStringLiteral( "labelsEnabled" ) ) )
+      mLabelsEnabled = node.toElement().attribute( QStringLiteral( "labelsEnabled" ) ).toInt();
+    else
+      mLabelsEnabled = true;
+
     // get and set the blend mode if it exists
     QDomNode blendModeNode = node.namedItem( QStringLiteral( "blendMode" ) );
     if ( !blendModeNode.isNull() )
@@ -2224,6 +2236,7 @@ bool QgsVectorLayer::writeStyle( QDomNode &node, QDomDocument &doc, QString &err
       QDomElement labelingElement = mLabeling->save( doc, context );
       node.appendChild( labelingElement );
     }
+    mapLayerNode.setAttribute( QStringLiteral( "labelsEnabled" ), mLabelsEnabled ? QStringLiteral( "1" ) : QStringLiteral( "0" ) );
 
     // save the simplification drawing settings
     mapLayerNode.setAttribute( QStringLiteral( "simplifyDrawingHints" ), QString::number( mSimplifyMethod.simplifyHints() ) );
@@ -3711,6 +3724,7 @@ double QgsVectorLayer::opacity() const
 void QgsVectorLayer::readSldLabeling( const QDomNode &node )
 {
   setLabeling( nullptr ); // start with no labeling
+  setLabelsEnabled( false );
 
   QDomElement element = node.toElement();
   if ( element.isNull() )
@@ -3931,6 +3945,7 @@ void QgsVectorLayer::readSldLabeling( const QDomNode &node )
   format.setBuffer( bufferSettings );
   settings.setFormat( format );
   setLabeling( new QgsVectorLayerSimpleLabeling( settings ) );
+  setLabelsEnabled( true );
 }
 
 QgsEditFormConfig QgsVectorLayer::editFormConfig() const

src/core/qgsvectorlayer.h

@@ -695,9 +695,22 @@ class CORE_EXPORT QgsVectorLayer : public QgsMapLayer, public QgsExpressionConte
      * Returns whether the layer contains labels which are enabled and should be drawn.
      * \returns true if layer contains enabled labels
      * \since QGIS 2.9
+     *
+     * \see setLabelsEnabled()
      */
     bool labelsEnabled() const;
 
+    /**
+     * Sets whether labels should be \a enabled for the layer.
+     *
+     * \note Labels will only be rendered if labelsEnabled() is true and a labeling
+     * object is returned by labeling().
+     *
+     * \see labelsEnabled()
+     * \see labeling()
+     */
+    void setLabelsEnabled( bool enabled );
+
     /**
      * Returns whether the layer contains diagrams which are enabled and should be drawn.
      * \returns true if layer contains enabled diagrams
@@ -1249,13 +1262,17 @@ class CORE_EXPORT QgsVectorLayer : public QgsMapLayer, public QgsExpressionConte
 
     /**
      * Access to const labeling configuration. May be null if labeling is not used.
+     * \note Labels will only be rendered if labelsEnabled() returns true.
      * \since QGIS 3.0
+     * \see labelsEnabled()
      */
     const QgsAbstractVectorLayerLabeling *labeling() const SIP_SKIP { return mLabeling; }
 
     /**
      * Access to labeling configuration. May be null if labeling is not used.
+     * \note Labels will only be rendered if labelsEnabled() returns true.
      * \since QGIS 3.0
+     * \see labelsEnabled()
      */
     QgsAbstractVectorLayerLabeling *labeling() { return mLabeling; }
 
@@ -2339,6 +2356,9 @@ class CORE_EXPORT QgsVectorLayer : public QgsMapLayer, public QgsExpressionConte
     //! Labeling configuration
     QgsAbstractVectorLayerLabeling *mLabeling = nullptr;
 
+    //! True if labels are enabled
+    bool mLabelsEnabled = false;
+
     //! Whether 'labeling font not found' has be shown for this layer (only show once in QgsMessageBar, on first rendering)
     bool mLabelFontNotFoundNotified = false;
 

src/core/qgsvectorlayerrenderer.cpp

@@ -480,7 +480,7 @@ void QgsVectorLayerRenderer::prepareLabeling( QgsVectorLayer *layer, QSet<QStrin
 {
   if ( QgsLabelingEngine *engine2 = mContext.labelingEngine() )
   {
-    if ( layer->labeling() )
+    if ( layer->labelsEnabled() )
     {
       mLabelProvider = layer->labeling()->provider( layer );
       if ( mLabelProvider )

src/server/services/wms/qgswmsrenderer.cpp

@@ -2556,6 +2556,7 @@ namespace QgsWms
 
         QgsVectorLayerSimpleLabeling *simpleLabeling = new QgsVectorLayerSimpleLabeling( palSettings );
         layer->setLabeling( simpleLabeling );
+        layer->setLabelsEnabled( true );
       }
       fet.setGeometry( param.mGeom );
 

tests/src/core/testqgsdxfexport.cpp

@@ -186,6 +186,7 @@ void TestQgsDxfExport::testMtext()
   format.setColor( QColor( 200, 0, 200 ) );
   settings.setFormat( format );
   mPointLayer->setLabeling( new QgsVectorLayerSimpleLabeling( settings ) );
+  mPointLayer->setLabelsEnabled( true );
 
   QgsDxfExport d;
   d.addLayers( QList< QPair< QgsVectorLayer *, int > >() << qMakePair( mPointLayer, -1 ) );
@@ -247,6 +248,7 @@ void TestQgsDxfExport::testText()
   format.setColor( QColor( 200, 0, 200 ) );
   settings.setFormat( format );
   mPointLayer->setLabeling( new QgsVectorLayerSimpleLabeling( settings ) );
+  mPointLayer->setLabelsEnabled( true );
 
   QgsDxfExport d;
   d.addLayers( QList< QPair< QgsVectorLayer *, int > >() << qMakePair( mPointLayer, -1 ) );

tests/src/core/testqgslabelingengine.cpp

@@ -134,6 +134,7 @@ void TestQgsLabelingEngine::testBasic()
   setDefaultLabelParams( settings );
 
   vl->setLabeling( new QgsVectorLayerSimpleLabeling( settings ) );  // TODO: this should not be necessary!
+  vl->setLabelsEnabled( true );
 
   QgsLabelingEngine engine;
   engine.setMapSettings( mapSettings );
@@ -246,6 +247,7 @@ void TestQgsLabelingEngine::testRuleBased()
   root->appendChild( new QgsRuleBasedLabeling::Rule( new QgsPalLayerSettings( s2 ), 0, 0, QStringLiteral( "Class = 'Jet'" ) ) );
 
   vl->setLabeling( new QgsRuleBasedLabeling( root ) );
+  vl->setLabelsEnabled( true );
   //setDefaultLabelParams( vl );
 
   QgsMapRendererSequentialJob job( mapSettings );
@@ -653,6 +655,7 @@ void TestQgsLabelingEngine::testRotateHidePartial()
   vl2->dataProvider()->addFeature( f );
 
   vl2->setLabeling( new QgsVectorLayerSimpleLabeling( settings ) );  // TODO: this should not be necessary!
+  vl2->setLabelsEnabled( true );
 
   // make a fake render context
   QSize size( 640, 480 );

tests/src/core/testqgsmaprotation.cpp

@@ -207,6 +207,7 @@ void TestQgsMapRotation::linesLayer()
   format.setSize( 16 );
   palSettings.setFormat( format );
   mLinesLayer->setLabeling( new QgsVectorLayerSimpleLabeling( palSettings ) );
+  mLinesLayer->setLabelsEnabled( true );
 
   QVERIFY( success );
   mMapSettings->setExtent( mLinesLayer->extent() ); //QgsRectangle(-150,-150,150,150) );