Allow labels to be toggled in map views

Another step toward feature parity with overview panel

python/gui/qgsmapcanvas.sip

@@ -25,6 +25,7 @@ class QgsMapCanvas : QGraphicsView
     void setCurrentLayer( QgsMapLayer *layer );
     const QgsMapSettings &mapSettings() const /KeepReference/;
     void setDestinationCrs( const QgsCoordinateReferenceSystem &crs );
+    void setMapSettingsFlags( QgsMapSettings::Flags flags );
     const QgsLabelingResults *labelingResults() const;
     void setCachingEnabled( bool enabled );
     bool isCachingEnabled() const;

src/app/qgisapp.cpp

@@ -11851,6 +11851,7 @@ void QgisApp::writeProject( QDomDocument &doc )
     node.setAttribute( QStringLiteral( "showExtent" ), w->isMainCanvasExtentVisible() );
     node.setAttribute( QStringLiteral( "scaleSynced" ), w->isViewScaleSynchronized() );
     node.setAttribute( QStringLiteral( "scaleFactor" ), w->scaleFactor() );
+    node.setAttribute( QStringLiteral( "showLabels" ), w->labelsVisible() );
     mapViewNode.appendChild( node );
   }
   qgisNode.appendChild( mapViewNode );
@@ -11890,6 +11891,7 @@ void QgisApp::readProject( const QDomDocument &doc )
       bool showExtent = elementNode.attribute( QStringLiteral( "showExtent" ), QStringLiteral( "0" ) ).toInt();
       bool scaleSynced = elementNode.attribute( QStringLiteral( "scaleSynced" ), QStringLiteral( "0" ) ).toInt();
       double scaleFactor = elementNode.attribute( QStringLiteral( "scaleFactor" ), QStringLiteral( "1" ) ).toDouble();
+      bool showLabels = elementNode.attribute( QStringLiteral( "showLabels" ), QStringLiteral( "1" ) ).toInt();
       Qt::DockWidgetArea area = static_cast< Qt::DockWidgetArea >( elementNode.attribute( QStringLiteral( "area" ), QString::number( Qt::RightDockWidgetArea ) ).toInt() );
 
       QgsMapCanvasDockWidget *mapCanvasDock = createNewMapCanvasDock( mapName, floating, QRect( x, y, w, h ), area );
@@ -11901,6 +11903,7 @@ void QgisApp::readProject( const QDomDocument &doc )
       mapCanvasDock->setScaleFactor( scaleFactor );
       mapCanvasDock->setViewScaleSynchronized( scaleSynced );
       mapCanvasDock->setMainCanvasExtentVisible( showExtent );
+      mapCanvasDock->setLabelsVisible( showLabels );
     }
   }
 }

src/app/qgsmapcanvasdockwidget.cpp

@@ -105,6 +105,7 @@ QgsMapCanvasDockWidget::QgsMapCanvasDockWidget( const QString &name, QWidget *pa
   settingsMenu->addAction( mActionShowAnnotations );
   settingsMenu->addAction( mActionShowCursor );
   settingsMenu->addAction( mActionShowExtent );
+  settingsMenu->addAction( mActionShowLabels );
   settingsMenu->addSeparator();
   settingsMenu->addAction( mActionSetCrs );
   settingsMenu->addAction( mActionRename );
@@ -118,6 +119,8 @@ QgsMapCanvasDockWidget::QgsMapCanvasDockWidget( const QString &name, QWidget *pa
   connect( mActionShowCursor, &QAction::toggled, this, [ = ]( bool checked ) { mXyMarker->setVisible( checked ); } );
   mActionShowExtent->setChecked( false );
   connect( mActionShowExtent, &QAction::toggled, this, [ = ]( bool checked ) { mExtentRubberBand->setVisible( checked ); updateExtentRect(); } );
+  mActionShowLabels->setChecked( true );
+  connect( mActionShowLabels, &QAction::toggled, this, &QgsMapCanvasDockWidget::showLabels );
 
   mScaleCombo = settingsAction->scaleCombo();
   mRotationEdit = settingsAction->rotationSpinBox();
@@ -273,6 +276,16 @@ bool QgsMapCanvasDockWidget::isViewScaleSynchronized() const
   return mSyncScaleCheckBox->isChecked();
 }
 
+void QgsMapCanvasDockWidget::setLabelsVisible( bool enabled )
+{
+  mActionShowLabels->setChecked( enabled );
+}
+
+bool QgsMapCanvasDockWidget::labelsVisible() const
+{
+  return mActionShowLabels->isChecked();
+}
+
 double QgsMapCanvasDockWidget::scaleFactor() const
 {
   return mScaleFactorWidget->value();
@@ -446,6 +459,16 @@ void QgsMapCanvasDockWidget::updateExtentRect()
   mExtentRubberBand->setToGeometry( g, nullptr );
 }
 
+void QgsMapCanvasDockWidget::showLabels( bool show )
+{
+  QgsMapSettings::Flags flags = mMapCanvas->mapSettings().flags();
+  if ( show )
+    flags = flags | QgsMapSettings::DrawLabeling;
+  else
+    flags = flags & ~QgsMapSettings::DrawLabeling;
+  mMapCanvas->setMapSettingsFlags( flags );
+}
+
 QgsMapSettingsAction::QgsMapSettingsAction( QWidget *parent )
   : QWidgetAction( parent )
 {

src/app/qgsmapcanvasdockwidget.h

@@ -118,6 +118,18 @@ class APP_EXPORT QgsMapCanvasDockWidget : public QgsDockWidget, private Ui::QgsM
      */
     bool isViewScaleSynchronized() const;
 
+    /**
+     * Sets whether labels should be rendered in the view.
+     * @see labelsVisible()
+     */
+    void setLabelsVisible( bool enabled );
+
+    /**
+     * Returns whether labels are rendered in the view.
+     * @see setLabelsVisible()
+     */
+    bool labelsVisible() const;
+
   signals:
 
     void renameTriggered();
@@ -136,6 +148,8 @@ class APP_EXPORT QgsMapCanvasDockWidget : public QgsDockWidget, private Ui::QgsM
     void syncMarker( const QgsPoint &p );
     void mapScaleChanged();
     void updateExtentRect();
+    void showLabels( bool show );
+
 
   private:
 

src/gui/qgsmapcanvas.cpp

@@ -385,6 +385,13 @@ void QgsMapCanvas::setDestinationCrs( const QgsCoordinateReferenceSystem &crs )
   emit destinationCrsChanged();
 }
 
+void QgsMapCanvas::setMapSettingsFlags( QgsMapSettings::Flags flags )
+{
+  mSettings.setFlags( flags );
+  clearCache();
+  refresh();
+}
+
 const QgsLabelingResults *QgsMapCanvas::labelingResults() const
 {
   return mLabelingResults;

src/gui/qgsmapcanvas.h

@@ -108,6 +108,12 @@ class GUI_EXPORT QgsMapCanvas : public QGraphicsView
     //! @note added in 2.4
     void setDestinationCrs( const QgsCoordinateReferenceSystem &crs );
 
+    /**
+     * Resets the \a flags for the canvas' map settings.
+     * @note added in QGIS 3.0
+     */
+    void setMapSettingsFlags( QgsMapSettings::Flags flags );
+
     //! Get access to the labeling results (may be null)
     //! @note added in 2.4
     const QgsLabelingResults *labelingResults() const;

src/ui/qgsmapcanvasdockwidgetbase.ui

@@ -159,6 +159,14 @@
     <string>Show Main Canvas Extent</string>
    </property>
   </action>
+  <action name="mActionShowLabels">
+   <property name="checkable">
+    <bool>true</bool>
+   </property>
+   <property name="text">
+    <string>Show Labels</string>
+   </property>
+  </action>
  </widget>
  <customwidgets>
   <customwidget>