[labeling] Fix data-defined tab distance property

src/core/labeling/qgspallabeling.cpp

@@ -2104,6 +2104,34 @@ std::unique_ptr<QgsLabelFeature> QgsPalLayerSettings::registerFeatureWithDetails
     parseDropShadow( context );
   }
 
+  if ( dataDefinedValues.contains( QgsPalLayerSettings::Property::TabStopDistance ) )
+  {
+    QList<QgsTextFormat::Tab> tabPositions;
+    if ( dataDefinedValues.value( QgsPalLayerSettings::Property::TabStopDistance ).userType() == QMetaType::Type::QVariantList )
+    {
+      const QVariantList parts = dataDefinedValues.value( QgsPalLayerSettings::Property::TabStopDistance ).toList();
+      for ( const QVariant &part : parts )
+      {
+        tabPositions.append( QgsTextFormat::Tab( part.toDouble() ) );
+      }
+      evaluatedFormat.setTabPositions( tabPositions );
+    }
+    else if ( dataDefinedValues.value( QgsPalLayerSettings::Property::TabStopDistance ).userType() == QMetaType::Type::QStringList )
+    {
+      const QStringList parts = dataDefinedValues.value( QgsPalLayerSettings::Property::TabStopDistance ).toStringList();
+      for ( const QString &part : parts )
+      {
+        tabPositions.append( QgsTextFormat::Tab( part.toDouble() ) );
+      }
+      evaluatedFormat.setTabPositions( tabPositions );
+    }
+    else
+    {
+      evaluatedFormat.setTabPositions( tabPositions );
+      evaluatedFormat.setTabStopDistance( dataDefinedValues.value( QgsPalLayerSettings::Property::TabStopDistance ).toDouble() );
+    }
+  }
+
   evaluatedFormat.setFont( labelFont );
   // undo scaling by symbology reference scale, as this would have been applied in the previous call to QgsTextRenderer::sizeToPixel and we risk
   // double-applying it if we don't re-adjust, since all the text format metric calculations assume an unscaled format font size is present
@@ -2150,6 +2178,7 @@ std::unique_ptr<QgsLabelFeature> QgsPalLayerSettings::registerFeatureWithDetails
   {
     capitalization = static_cast< Qgis::Capitalization >( mFormat.font().capitalization() );
   }
+
   // data defined font capitalization?
   if ( mDataDefinedProperties.isActive( QgsPalLayerSettings::Property::FontCase ) )
   {
@@ -3684,6 +3713,15 @@ void QgsPalLayerSettings::parseTextFormatting( QgsRenderContext &context )
     evalAutoWrapLength = exprVal.toInt();
   }
 
+  if ( mDataDefinedProperties.isActive( QgsPalLayerSettings::Property::TabStopDistance ) )
+  {
+    exprVal = mDataDefinedProperties.value( QgsPalLayerSettings::Property::TabStopDistance, context.expressionContext() );
+    if ( !QgsVariantUtils::isNull( exprVal ) )
+    {
+      dataDefinedValues.insert( QgsPalLayerSettings::Property::TabStopDistance, exprVal );
+    }
+  }
+
   // data defined multiline height?
   dataDefinedValEval( DDDouble, QgsPalLayerSettings::Property::MultiLineHeight, exprVal, context.expressionContext() );
 
@@ -4411,6 +4449,36 @@ void QgsPalLabeling::dataDefinedTextFormatting( QgsPalLayerSettings &tmpLyr,
     tmpLyr.setFormat( format );
   }
 
+  if ( ddValues.contains( QgsPalLayerSettings::Property::TabStopDistance ) )
+  {
+    QgsTextFormat format = tmpLyr.format();
+    QList<QgsTextFormat::Tab> tabPositions;
+    if ( ddValues.value( QgsPalLayerSettings::Property::TabStopDistance ).userType() == QMetaType::Type::QVariantList )
+    {
+      const QVariantList parts = ddValues.value( QgsPalLayerSettings::Property::TabStopDistance ).toList();
+      for ( const QVariant &part : parts )
+      {
+        tabPositions.append( QgsTextFormat::Tab( part.toDouble() ) );
+      }
+      format.setTabPositions( tabPositions );
+    }
+    else if ( ddValues.value( QgsPalLayerSettings::Property::TabStopDistance ).userType() == QMetaType::Type::QStringList )
+    {
+      const QStringList parts = ddValues.value( QgsPalLayerSettings::Property::TabStopDistance ).toStringList();
+      for ( const QString &part : parts )
+      {
+        tabPositions.append( QgsTextFormat::Tab( part.toDouble() ) );
+      }
+      format.setTabPositions( tabPositions );
+    }
+    else
+    {
+      format.setTabPositions( tabPositions );
+      format.setTabStopDistance( ddValues.value( QgsPalLayerSettings::Property::TabStopDistance ).toDouble() );
+    }
+    tmpLyr.setFormat( format );
+  }
+
   if ( ddValues.contains( QgsPalLayerSettings::Property::MultiLineAlignment ) )
   {
     tmpLyr.multilineAlign = static_cast< Qgis::LabelMultiLineAlignment >( ddValues.value( QgsPalLayerSettings::Property::MultiLineAlignment ).toInt() );
@@ -4449,7 +4517,6 @@ void QgsPalLabeling::dataDefinedTextFormatting( QgsPalLayerSettings &tmpLyr,
     {
       tmpLyr.lineSettings().setReverseDirectionSymbol( ddValues.value( QgsPalLayerSettings::Property::DirSymbReverse ).toBool() );
     }
-
   }
 }
 

tests/src/core/testqgslabelingengine.cpp

@@ -123,6 +123,7 @@ class TestQgsLabelingEngine : public QgsTest
     void parallelOverrun();
     void testDataDefinedLabelAllParts();
     void testDataDefinedPlacementPositionPoint();
+    void testDataDefinedLabelTabs();
     void testVerticalOrientation();
     void testVerticalOrientationLetterLineSpacing();
     void testRotationBasedOrientationPoint();
@@ -5185,6 +5186,64 @@ void TestQgsLabelingEngine::testDataDefinedPlacementPositionPoint()
   vl->setLabeling( nullptr );
 }
 
+void TestQgsLabelingEngine::testDataDefinedLabelTabs()
+{
+  // test curved label rendering with tab characters
+  QgsPalLayerSettings settings;
+  setDefaultLabelParams( settings );
+
+  QgsTextFormat format = settings.format();
+  format.setSize( 30 );
+  format.setColor( QColor( 0, 0, 0 ) );
+  format.setTabStopDistance( 28 );
+  format.setTabStopDistanceUnit( Qgis::RenderUnit::Millimeters );
+  settings.setFormat( format );
+  settings.dataDefinedProperties().setProperty( QgsPalLayerSettings::Property::TabStopDistance, QgsProperty::fromExpression( QStringLiteral( "48" ) ) );
+
+  settings.fieldName = QStringLiteral( "'test of\ttab\ttext'" );
+  settings.isExpression = true;
+  settings.placement = Qgis::LabelPlacement::Horizontal;
+  settings.labelPerPart = false;
+  settings.lineSettings().setLineAnchorPercent( 0.5 );
+  settings.lineSettings().setAnchorType( QgsLabelLineSettings::AnchorType::Strict );
+  settings.lineSettings().setPlacementFlags( Qgis::LabelLinePlacementFlag::AboveLine | Qgis::LabelLinePlacementFlag::MapOrientation );
+  settings.lineSettings().setAnchorTextPoint( QgsLabelLineSettings::AnchorTextPoint::CenterOfText );
+
+  std::unique_ptr<QgsVectorLayer> vl2( new QgsVectorLayer( QStringLiteral( "LineString?crs=epsg:3946&field=id:integer" ), QStringLiteral( "vl" ), QStringLiteral( "memory" ) ) );
+  vl2->setRenderer( new QgsNullSymbolRenderer() );
+
+  QgsFeature f;
+  f.setAttributes( QgsAttributes() << 1 );
+  f.setGeometry( QgsGeometry::fromWkt( QStringLiteral( "LineString (190000 5000010, 190100 5000000, 190200 5000000)" ) ) );
+  QVERIFY( vl2->dataProvider()->addFeature( f ) );
+
+  vl2->setLabeling( new QgsVectorLayerSimpleLabeling( settings ) ); // TODO: this should not be necessary!
+  vl2->setLabelsEnabled( true );
+
+  // make a fake render context
+  const QSize size( 640, 480 );
+  QgsMapSettings mapSettings;
+  mapSettings.setLabelingEngineSettings( createLabelEngineSettings() );
+  mapSettings.setDestinationCrs( vl2->crs() );
+
+  mapSettings.setOutputSize( size );
+  mapSettings.setExtent( f.geometry().boundingBox() );
+  mapSettings.setLayers( QList<QgsMapLayer *>() << vl2.get() );
+  mapSettings.setOutputDpi( 96 );
+
+  QgsLabelingEngineSettings engineSettings = mapSettings.labelingEngineSettings();
+  engineSettings.setFlag( Qgis::LabelingFlag::UsePartialCandidates, false );
+  engineSettings.setFlag( Qgis::LabelingFlag::DrawCandidates, true );
+  mapSettings.setLabelingEngineSettings( engineSettings );
+
+  QgsMapRendererSequentialJob job( mapSettings );
+  job.start();
+  job.waitForFinished();
+
+  QImage img = job.renderedImage();
+  QGSVERIFYIMAGECHECK( "data_defined_tabs", "data_defined_tabs", img, QString(), 20, QSize( 0, 0 ), 2 );
+}
+
 void TestQgsLabelingEngine::testVerticalOrientation()
 {
   const QSize size( 640, 480 );