[layout] When newline characters are entered as part of a legend item's text,

correctly respect these while rendering legend

src/core/qgslegendsettings.cpp

@@ -53,15 +53,20 @@ QStringList QgsLegendSettings::evaluateItemText( const QString &text, const QgsE
   return splitStringForWrapping( textToRender );
 }
 
-QStringList QgsLegendSettings::splitStringForWrapping( const QString &stringToSplt ) const
+QStringList QgsLegendSettings::splitStringForWrapping( const QString &stringToSplit ) const
 {
-  QStringList list;
+  const QStringList lines = stringToSplit.split( '\n' );
+
   // If the string contains nothing then just return the string without splitting.
-  if ( wrapChar().count() == 0 )
-    list << stringToSplt;
-  else
-    list = stringToSplt.split( wrapChar() );
-  return list;
+  if ( wrapChar().isEmpty() )
+    return lines;
+
+  QStringList res;
+  for ( const QString &line : lines )
+  {
+    res.append( line.split( wrapChar() ) );
+  }
+  return res;
 }
 
 #define FONT_WORKAROUND_SCALE 10 //scale factor for upscaling fontsize and downscaling painter

tests/src/core/testqgslegendrenderer.cpp

@@ -131,6 +131,7 @@ class TestQgsLegendRenderer : public QObject
     void testModel();
 
     void testBasic();
+    void testMultiline();
     void testEffects();
     void testBigMarker();
 
@@ -318,6 +319,26 @@ void TestQgsLegendRenderer::testBasic()
   QVERIFY( _verifyImage( testName, mReport ) );
 }
 
+void TestQgsLegendRenderer::testMultiline()
+{
+  QString testName = QStringLiteral( "legend_multiline" );
+
+  QgsLayerTreeModel legendModel( mRoot );
+
+  legendModel.findLegendNode( mVL1->id(), QString() );
+
+  QgsLayerTreeLayer *layer = legendModel.rootGroup()->findLayer( mVL1 );
+  layer->setCustomProperty( QStringLiteral( "legend/title-label" ), QStringLiteral( "some legend text\nwith newline\ncharacters in it" ) );
+
+  QgsLayerTreeModelLegendNode *embeddedNode = legendModel.legendNodeEmbeddedInParent( layer );
+  embeddedNode->setUserLabel( QString() );
+
+  QgsLegendSettings settings;
+  _setStandardTestFont( settings, QStringLiteral( "Bold" ) );
+  _renderLegend( testName, &legendModel, settings );
+  QVERIFY( _verifyImage( testName, mReport ) );
+}
+
 void TestQgsLegendRenderer::testEffects()
 {
   QString testName = QStringLiteral( "legend_effects" );