[CMYK] Generate a valid PDF/X-4 file

src/core/layout/qgslayoutexporter.cpp

@@ -26,6 +26,7 @@
 #include "qgslayoutgeopdfexporter.h"
 #include "qgslinestring.h"
 #include "qgsmessagelog.h"
+#include "qgsprojectstylesettings.h"
 #include "qgslabelingresults.h"
 #include "qgssettingsentryimpl.h"
 #include "qgssettingstree.h"
@@ -36,6 +37,11 @@
 #include <QBuffer>
 #include <QTimeZone>
 #include <QTextStream>
+#if QT_VERSION >= QT_VERSION_CHECK(6, 8, 0)
+#include <QColorSpace>
+#include <QPdfOutputIntent>
+#endif
+#include <QXmlStreamWriter>
 
 #include "gdal.h"
 #include "cpl_conv.h"
@@ -650,8 +656,8 @@ QgsLayoutExporter::ExportResult QgsLayoutExporter::exportToPdf( const QString &f
       {
         // copy layout metadata to GeoPDF export settings
         details.author = mLayout->project()->metadata().author();
-        details.producer = QStringLiteral( "QGIS %1" ).arg( Qgis::version() );
-        details.creator = QStringLiteral( "QGIS %1" ).arg( Qgis::version() );
+        details.producer = getCreator();
+        details.creator = getCreator();
         details.creationDateTime = mLayout->project()->metadata().creationDateTime();
         details.subject = mLayout->project()->metadata().abstract();
         details.title = mLayout->project()->metadata().title();
@@ -1264,7 +1270,7 @@ QMap<QString, QgsLabelingResults *> QgsLayoutExporter::takeLabelingResults()
   return res;
 }
 
-void QgsLayoutExporter::preparePrintAsPdf( QgsLayout *layout, QPagedPaintDevice *device, const QString &filePath )
+void QgsLayoutExporter::preparePrintAsPdf( QgsLayout *layout, QPdfWriter *device, const QString &filePath )
 {
   QFileInfo fi( filePath );
   QDir dir;
@@ -1275,14 +1281,56 @@ void QgsLayoutExporter::preparePrintAsPdf( QgsLayout *layout, QPagedPaintDevice
 
   updatePrinterPageSize( layout, device, firstPageToBeExported( layout ) );
 
+  // force a non empty title to avoid invalid (according to specification) PDF/X-4
+  const QString title = !layout->project() || layout->project()->metadata().title().isEmpty() ?
+                        fi.baseName() : layout->project()->metadata().title();
+
+  device->setTitle( title );
+
+  QPagedPaintDevice::PdfVersion pdfVersion = QPagedPaintDevice::PdfVersion_1_4;
+
+#if QT_VERSION >= QT_VERSION_CHECK(6, 8, 0)
+
+  if ( const QgsProjectStyleSettings *styleSettings = ( layout->project() ? layout->project()->styleSettings() : nullptr ) )
+  {
+    // We don't want to let AUTO color model because we could end up writing RGB colors with a CMYK
+    // output intent color model and vice versa, so we force color conversion
+    switch ( styleSettings->colorModel() )
+    {
+      case Qgis::ColorModel::Cmyk:
+        device->setColorModel( QPdfWriter::ColorModel::CMYK );
+        break;
+
+      case Qgis::ColorModel::Rgb:
+        device->setColorModel( QPdfWriter::ColorModel::RGB );
+        break;
+    }
+
+    const QColorSpace colorSpace = styleSettings->colorSpace();
+    if ( colorSpace.isValid() )
+    {
+      QPdfOutputIntent outputIntent;
+      outputIntent.setOutputProfile( colorSpace );
+      device->setOutputIntent( outputIntent );
+
+      // PDF/X-4 standard allows PDF to be printing ready and is only possible if a color space has been set
+      pdfVersion = QPagedPaintDevice::PdfVersion_X4;
+    }
+  }
+
+#endif
+
+  device->setPdfVersion( pdfVersion );
+  setXmpMetadata( device, layout );
+
   // TODO: add option for this in layout
   // May not work on Windows or non-X11 Linux. Works fine on Mac using QPrinter::NativeFormat
   //printer.setFontEmbeddingEnabled( true );
 
 #if defined(HAS_KDE_QT5_PDF_TRANSFORM_FIX) || QT_VERSION >= QT_VERSION_CHECK(6, 3, 0)
   // paint engine hack not required, fixed upstream
 #else
-  QgsPaintEngineHack::fixEngineFlags( device->paintEngine() );
+  QgsPaintEngineHack::fixEngineFlags( static_cast<QPaintDevice *>( device )->paintEngine() );
 #endif
 }
 
@@ -1529,7 +1577,7 @@ void QgsLayoutExporter::appendMetadataToSvg( QDomDocument &svg ) const
   };
 
   addAgentNode( QStringLiteral( "dc:creator" ), metadata.author() );
-  addAgentNode( QStringLiteral( "dc:publisher" ), QStringLiteral( "QGIS %1" ).arg( Qgis::version() ) );
+  addAgentNode( QStringLiteral( "dc:publisher" ), getCreator() );
 
   // keywords
   {
@@ -1714,7 +1762,7 @@ bool QgsLayoutExporter::georeferenceOutputPrivate( const QString &file, QgsLayou
       GDALSetMetadataItem( outputDS.get(), "CREATION_DATE", creationDateString.toUtf8().constData(), nullptr );
 
       GDALSetMetadataItem( outputDS.get(), "AUTHOR", mLayout->project()->metadata().author().toUtf8().constData(), nullptr );
-      const QString creator = QStringLiteral( "QGIS %1" ).arg( Qgis::version() );
+      const QString creator = getCreator();
       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 );
@@ -2172,7 +2220,7 @@ bool QgsLayoutExporter::saveImage( const QImage &image, const QString &imageFile
   if ( projectForMetadata )
   {
     w.setText( QStringLiteral( "Author" ), projectForMetadata->metadata().author() );
-    const QString creator = QStringLiteral( "QGIS %1" ).arg( Qgis::version() );
+    const QString creator = getCreator();
     w.setText( QStringLiteral( "Creator" ), creator );
     w.setText( QStringLiteral( "Producer" ), creator );
     w.setText( QStringLiteral( "Subject" ), projectForMetadata->metadata().abstract() );
@@ -2190,3 +2238,129 @@ bool QgsLayoutExporter::saveImage( const QImage &image, const QString &imageFile
   }
   return w.write( image );
 }
+
+QString QgsLayoutExporter::getCreator()
+{
+  return QStringLiteral( "QGIS %1" ).arg( Qgis::version() );
+}
+
+void QgsLayoutExporter::setXmpMetadata( QPdfWriter *pdfWriter, QgsLayout *layout )
+{
+#if QT_VERSION >= QT_VERSION_CHECK(6, 8, 0)
+  QUuid documentId = pdfWriter->documentId();
+#else
+  QUuid documentId = QUuid::createUuid();
+#endif
+
+  // XMP metadata date format differs from PDF dictionary one
+  const QDateTime creationDateTime = layout->project() ? layout->project()->metadata().creationDateTime() : QDateTime();
+  const QString metaDataDate = creationDateTime.isValid() ? creationDateTime.toOffsetFromUtc( creationDateTime.offsetFromUtc() ).toString( Qt::ISODate ) : QString();
+  const QString title = pdfWriter->title();
+  const QString creator = getCreator();
+  const QString producer = creator;
+  const QString author = layout->project() ? layout->project()->metadata().author() : QString();
+
+  // heavily inspired from qpdf.cpp QPdfEnginePrivate::writeXmpDocumentMetaData
+
+  const QLatin1String xmlNS( "http://www.w3.org/XML/1998/namespace" );
+  const QLatin1String adobeNS( "adobe:ns:meta/" );
+  const QLatin1String rdfNS( "http://www.w3.org/1999/02/22-rdf-syntax-ns#" );
+  const QLatin1String dcNS( "http://purl.org/dc/elements/1.1/" );
+  const QLatin1String xmpNS( "http://ns.adobe.com/xap/1.0/" );
+  const QLatin1String xmpMMNS( "http://ns.adobe.com/xap/1.0/mm/" );
+  const QLatin1String pdfNS( "http://ns.adobe.com/pdf/1.3/" );
+  const QLatin1String pdfaidNS( "http://www.aiim.org/pdfa/ns/id/" );
+  const QLatin1String pdfxidNS( "http://www.npes.org/pdfx/ns/id/" );
+
+  QByteArray xmpMetadata;
+  QBuffer output( &xmpMetadata );
+  output.open( QIODevice::WriteOnly );
+  output.write( "<?xpacket begin='' ?>" );
+
+  QXmlStreamWriter w( &output );
+  w.setAutoFormatting( true );
+  w.writeNamespace( adobeNS, "x" );  //#spellok
+  w.writeNamespace( rdfNS, "rdf" );  //#spellok
+  w.writeNamespace( dcNS, "dc" );  //#spellok
+  w.writeNamespace( xmpNS, "xmp" );  //#spellok
+  w.writeNamespace( xmpMMNS, "xmpMM" );  //#spellok
+  w.writeNamespace( pdfNS, "pdf" );  //#spellok
+  w.writeNamespace( pdfaidNS, "pdfaid" );  //#spellok
+  w.writeNamespace( pdfxidNS, "pdfxid" );  //#spellok
+
+  w.writeStartElement( adobeNS, "xmpmeta" );
+  w.writeStartElement( rdfNS, "RDF" );
+
+  // DC
+  w.writeStartElement( rdfNS, "Description" );
+  w.writeAttribute( rdfNS, "about", "" );
+  w.writeStartElement( dcNS, "title" );
+  w.writeStartElement( rdfNS, "Alt" );
+  w.writeStartElement( rdfNS, "li" );
+  w.writeAttribute( xmlNS, "lang", "x-default" );
+  w.writeCharacters( title );
+  w.writeEndElement();
+  w.writeEndElement();
+  w.writeEndElement();
+
+  w.writeStartElement( dcNS, "creator" );
+  w.writeStartElement( rdfNS, "Seq" );
+  w.writeStartElement( rdfNS, "li" );
+  w.writeCharacters( author );
+  w.writeEndElement();
+  w.writeEndElement();
+  w.writeEndElement();
+
+  w.writeEndElement();
+
+  // PDF
+  w.writeStartElement( rdfNS, "Description" );
+  w.writeAttribute( rdfNS, "about", "" );
+  w.writeAttribute( pdfNS, "Producer", producer );
+  w.writeAttribute( pdfNS, "Trapped", "False" );
+  w.writeEndElement();
+
+  // XMP
+  w.writeStartElement( rdfNS, "Description" );
+  w.writeAttribute( rdfNS, "about", "" );
+  w.writeAttribute( xmpNS, "CreatorTool", creator );
+  w.writeAttribute( xmpNS, "CreateDate", metaDataDate );
+  w.writeAttribute( xmpNS, "ModifyDate", metaDataDate );
+  w.writeAttribute( xmpNS, "MetadataDate", metaDataDate );
+  w.writeEndElement();
+
+  // XMPMM
+  w.writeStartElement( rdfNS, "Description" );
+  w.writeAttribute( rdfNS, "about", "" );
+  w.writeAttribute( xmpMMNS, "DocumentID", "uuid:" + documentId.toString( QUuid::WithoutBraces ) );
+  w.writeAttribute( xmpMMNS, "VersionID", "1" );
+  w.writeAttribute( xmpMMNS, "RenditionClass", "default" );
+  w.writeEndElement();
+
+#if QT_VERSION >= QT_VERSION_CHECK(6, 8, 0)
+
+  // Version-specific
+  switch ( pdfWriter->pdfVersion() )
+  {
+    case QPagedPaintDevice::PdfVersion_1_4:
+    case QPagedPaintDevice::PdfVersion_A1b: // A1b and 1.6 are not used by QGIS
+    case QPagedPaintDevice::PdfVersion_1_6:
+      break;
+    case QPagedPaintDevice::PdfVersion_X4:
+      w.writeStartElement( rdfNS, "Description" );
+      w.writeAttribute( rdfNS, "about", "" );
+      w.writeAttribute( pdfxidNS, "GTS_PDFXVersion", "PDF/X-4" );
+      w.writeEndElement();
+      break;
+  }
+
+#endif
+
+  w.writeEndElement(); // </RDF>
+  w.writeEndElement(); // </xmpmeta>
+
+  w.writeEndDocument();
+  output.write( "<?xpacket end='w'?>" );
+
+  pdfWriter->setDocumentXmpMetadata( xmpMetadata );
+}

src/core/layout/qgslayoutexporter.h

@@ -742,7 +742,7 @@ class CORE_EXPORT QgsLayoutExporter
     /**
      * Prepare a \a device for printing a layout as a PDF, to the destination \a filePath.
      */
-    static void preparePrintAsPdf( QgsLayout *layout, QPagedPaintDevice *device, const QString &filePath );
+    static void preparePrintAsPdf( QgsLayout *layout, QPdfWriter *device, const QString &filePath );
 
     static void preparePrint( QgsLayout *layout, QPagedPaintDevice *device, bool setFirstPageSize = false );
 
@@ -777,6 +777,12 @@ class CORE_EXPORT QgsLayoutExporter
                                       const std::function<QString( QgsLayoutItem *item )> &getItemExportGroupFunc
                                     );
 
+    // Returns PDF creator (used also as producer)
+    static QString getCreator();
+
+    // Set PDF XMP metadata on pdfWriter for given layout
+    static void setXmpMetadata( QPdfWriter *pdfWriter, QgsLayout *layout );
+
     static QgsVectorSimplifyMethod createExportSimplifyMethod();
     static QgsMaskRenderSettings createExportMaskSettings();
     friend class TestQgsLayout;

tests/src/python/test_qgslayoutexporter.py

@@ -12,6 +12,10 @@
 import os
 import subprocess
 import tempfile
+import xml.etree.ElementTree as etree
+from uuid import UUID
+from io import StringIO
+
 from typing import Optional
 
 from osgeo import gdal
@@ -29,6 +33,7 @@
 from qgis.PyQt.QtPrintSupport import QPrinter
 from qgis.PyQt.QtSvg import QSvgRenderer
 from qgis.core import (
+    Qgis,
     QgsCoordinateReferenceSystem,
     QgsFeature,
     QgsFillSymbol,
@@ -445,8 +450,11 @@ def testExportToImage(self):
 
     def testExportToPdf(self):
         md = QgsProject.instance().metadata()
-        md.setTitle('proj title')
-        md.setAuthor('proj author')
+
+        projTitle = 'proj titlea /<é'
+        projAuthor = 'proj author /<é'
+        md.setTitle(projTitle)
+        md.setAuthor(projAuthor)
         md.setCreationDateTime(QDateTime(QDate(2011, 5, 3), QTime(9, 4, 5), QTimeZone(36000)))
         md.setIdentifier('proj identifier')
         md.setAbstract('proj abstract')
@@ -518,11 +526,62 @@ def testExportToPdf(self):
 
         d = gdal.Open(pdf_file_path)
         metadata = d.GetMetadata()
-        self.assertEqual(metadata['AUTHOR'], 'proj author')
+        self.assertEqual(metadata['AUTHOR'], projAuthor)
         self.assertEqual(metadata['CREATION_DATE'], "D:20110503090405+10'0'")
         self.assertEqual(metadata['KEYWORDS'], 'KWx: kw3,kw4;kw: kw1,kw2')
         self.assertEqual(metadata['SUBJECT'], 'proj abstract')
-        self.assertEqual(metadata['TITLE'], 'proj title')
+        self.assertEqual(metadata['TITLE'], projTitle)
+        qgisId = f"QGIS {Qgis.version()}"
+        self.assertEqual(metadata['CREATOR'], qgisId)
+
+        # check XMP metadata
+        xmpMetadata = d.GetMetadata("xml:XMP")
+        self.assertEqual(len(xmpMetadata), 1)
+        xmp = xmpMetadata[0]
+        self.assertTrue(xmp)
+        xmpDoc = etree.fromstring(xmp)
+        namespaces = dict([node for _, node in etree.iterparse(StringIO(xmp), events=['start-ns'])])
+
+        title = xmpDoc.findall("rdf:RDF/rdf:Description/dc:title/rdf:Alt/rdf:li", namespaces)
+        self.assertEqual(len(title), 1)
+        self.assertEqual(title[0].text, projTitle)
+
+        creator = xmpDoc.findall("rdf:RDF/rdf:Description/dc:creator/rdf:Seq/rdf:li", namespaces)
+        self.assertEqual(len(creator), 1)
+        self.assertEqual(creator[0].text, projAuthor)
+
+        producer = xmpDoc.findall("rdf:RDF/rdf:Description[@pdf:Producer]", namespaces)
+        self.assertEqual(len(producer), 1)
+        self.assertEqual(producer[0].attrib["{" + namespaces["pdf"] + "}" + "Producer"], qgisId)
+
+        producer2 = xmpDoc.findall("rdf:RDF/rdf:Description[@xmp:CreatorTool]", namespaces)
+        self.assertEqual(len(producer2), 1)
+        self.assertEqual(producer2[0].attrib["{" + namespaces["xmp"] + "}" + "CreatorTool"], qgisId)
+
+        creationDateTags = xmpDoc.findall("rdf:RDF/rdf:Description[@xmp:CreateDate]", namespaces)
+        self.assertEqual(len(creationDateTags), 1)
+        creationDate = creationDateTags[0].attrib["{" + namespaces["xmp"] + "}" + "CreateDate"]
+        self.assertEqual(creationDate, "2011-05-03T09:04:05+10:00")
+
+        metadataDateTags = xmpDoc.findall("rdf:RDF/rdf:Description[@xmp:MetadataDate]", namespaces)
+        self.assertEqual(len(metadataDateTags), 1)
+        metadataDate = metadataDateTags[0].attrib["{" + namespaces["xmp"] + "}" + "MetadataDate"]
+        self.assertEqual(metadataDate, "2011-05-03T09:04:05+10:00")
+
+        modifyDateTags = xmpDoc.findall("rdf:RDF/rdf:Description[@xmp:ModifyDate]", namespaces)
+        self.assertEqual(len(modifyDateTags), 1)
+        modifyDate = modifyDateTags[0].attrib["{" + namespaces["xmp"] + "}" + "ModifyDate"]
+        self.assertEqual(modifyDate, "2011-05-03T09:04:05+10:00")
+
+        docIdTags = xmpDoc.findall("rdf:RDF/rdf:Description[@xmpMM:DocumentID]", namespaces)
+        self.assertEqual(len(docIdTags), 1)
+        docId = docIdTags[0].attrib["{" + namespaces["xmpMM"] + "}" + "DocumentID"]
+        uuidValid = True
+        try:
+            test = UUID(docId)
+        except ValueError:
+            uuidValid = False
+        self.assertTrue(uuidValid)
 
     def testExportToPdfGeoreference(self):
         md = QgsProject.instance().metadata()