Fix metadata encoding in PDF exported from Map canvas and Print layout

Fixes #40265

src/core/layout/qgslayoutexporter.cpp

@@ -1593,14 +1593,14 @@ bool QgsLayoutExporter::georeferenceOutputPrivate( const QString &file, QgsLayou
           creationDateString += QStringLiteral( "%1'%2'" ).arg( offsetHours ).arg( offsetMins );
         }
       }
-      GDALSetMetadataItem( outputDS.get(), "CREATION_DATE", creationDateString.toLocal8Bit().constData(), nullptr );
+      GDALSetMetadataItem( outputDS.get(), "CREATION_DATE", creationDateString.toUtf8().constData(), nullptr );
 
-      GDALSetMetadataItem( outputDS.get(), "AUTHOR", mLayout->project()->metadata().author().toLocal8Bit().constData(), nullptr );
+      GDALSetMetadataItem( outputDS.get(), "AUTHOR", mLayout->project()->metadata().author().toUtf8().constData(), nullptr );
       const QString creator = QStringLiteral( "QGIS %1" ).arg( Qgis::version() );
-      GDALSetMetadataItem( outputDS.get(), "CREATOR", creator.toLocal8Bit().constData(), nullptr );
-      GDALSetMetadataItem( outputDS.get(), "PRODUCER", creator.toLocal8Bit().constData(), nullptr );
-      GDALSetMetadataItem( outputDS.get(), "SUBJECT", mLayout->project()->metadata().abstract().toLocal8Bit().constData(), nullptr );
-      GDALSetMetadataItem( outputDS.get(), "TITLE", mLayout->project()->metadata().title().toLocal8Bit().constData(), nullptr );
+      GDALSetMetadataItem( outputDS.get(), "CREATOR", creator.toUtf8().constData(), nullptr );
+      GDALSetMetadataItem( outputDS.get(), "PRODUCER", creator.toUtf8().constData(), nullptr );
+      GDALSetMetadataItem( outputDS.get(), "SUBJECT", mLayout->project()->metadata().abstract().toUtf8().constData(), nullptr );
+      GDALSetMetadataItem( outputDS.get(), "TITLE", mLayout->project()->metadata().title().toUtf8().constData(), nullptr );
 
       const QgsAbstractMetadataBase::KeywordMap keywords = mLayout->project()->metadata().keywords();
       QStringList allKeywords;
@@ -1609,7 +1609,7 @@ bool QgsLayoutExporter::georeferenceOutputPrivate( const QString &file, QgsLayou
         allKeywords.append( QStringLiteral( "%1: %2" ).arg( it.key(), it.value().join( ',' ) ) );
       }
       const QString keywordString = allKeywords.join( ';' );
-      GDALSetMetadataItem( outputDS.get(), "KEYWORDS", keywordString.toLocal8Bit().constData(), nullptr );
+      GDALSetMetadataItem( outputDS.get(), "KEYWORDS", keywordString.toUtf8().constData(), nullptr );
     }
 
     if ( t )

src/core/qgsmaprenderertask.cpp

@@ -345,14 +345,14 @@ bool QgsMapRendererTask::run()
                 creationDateString += QStringLiteral( "%1'%2'" ).arg( offsetHours ).arg( offsetMins );
               }
             }
-            GDALSetMetadataItem( outputDS.get(), "CREATION_DATE", creationDateString.toLocal8Bit().constData(), nullptr );
+            GDALSetMetadataItem( outputDS.get(), "CREATION_DATE", creationDateString.toUtf8().constData(), nullptr );
 
-            GDALSetMetadataItem( outputDS.get(), "AUTHOR", mGeoPdfExportDetails.author.toLocal8Bit().constData(), nullptr );
+            GDALSetMetadataItem( outputDS.get(), "AUTHOR", mGeoPdfExportDetails.author.toUtf8().constData(), nullptr );
             const QString creator = QStringLiteral( "QGIS %1" ).arg( Qgis::version() );
-            GDALSetMetadataItem( outputDS.get(), "CREATOR", creator.toLocal8Bit().constData(), nullptr );
-            GDALSetMetadataItem( outputDS.get(), "PRODUCER", creator.toLocal8Bit().constData(), nullptr );
-            GDALSetMetadataItem( outputDS.get(), "SUBJECT", mGeoPdfExportDetails.subject.toLocal8Bit().constData(), nullptr );
-            GDALSetMetadataItem( outputDS.get(), "TITLE", mGeoPdfExportDetails.title.toLocal8Bit().constData(), nullptr );
+            GDALSetMetadataItem( outputDS.get(), "CREATOR", creator.toUtf8().constData(), nullptr );
+            GDALSetMetadataItem( outputDS.get(), "PRODUCER", creator.toUtf8().constData(), nullptr );
+            GDALSetMetadataItem( outputDS.get(), "SUBJECT", mGeoPdfExportDetails.subject.toUtf8().constData(), nullptr );
+            GDALSetMetadataItem( outputDS.get(), "TITLE", mGeoPdfExportDetails.title.toUtf8().constData(), nullptr );
 
             const QgsAbstractMetadataBase::KeywordMap keywords = mGeoPdfExportDetails.keywords;
             QStringList allKeywords;
@@ -361,7 +361,7 @@ bool QgsMapRendererTask::run()
               allKeywords.append( QStringLiteral( "%1: %2" ).arg( it.key(), it.value().join( ',' ) ) );
             }
             const QString keywordString = allKeywords.join( ';' );
-            GDALSetMetadataItem( outputDS.get(), "KEYWORDS", keywordString.toLocal8Bit().constData(), nullptr );
+            GDALSetMetadataItem( outputDS.get(), "KEYWORDS", keywordString.toUtf8().constData(), nullptr );
           }
         }
         CPLSetThreadLocalConfigOption( "GDAL_PDF_DPI", nullptr );