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How to create the simplest possible PDFA 2b with Apache PDFBox that is compliant according to VeraPDF?

I am using Apache PDFBox to create a very simple pdf with one line of text with conformance to PDFA 2b and I want to use VeraPDF to check this pdf for conformance. Vera is telling me, that the pdf is not compliant and shows me two failed assertions:

  • TestAssertion [ruleId=RuleId [specification=ISO 19005-2:2011, clause=6.6.2.1, testNumber=1], status=failed, message=The Catalog dictionary of a conforming file shall contain the Metadata key whose value is a metadata stream as defined in ISO 32000-1:2008, 14.3.2., location=Location [level=CosDocument, context=root/document[0]], locationContext=null, errorMessage=null]
  • TestAssertion [ruleId=RuleId [specification=ISO 19005-2:2011, clause=6.2.4.3, testNumber=4], status=failed, message=DeviceGray shall only be used if a device independent DefaultGray colour space has been set when the DeviceGray colour space is used, or if a PDF/A OutputIntent is present., location=Location [level=CosDocument, context=root/document[0]/pages[0](4 0 obj PDPage)/contentStream[0](6 0 obj PDContentStream)/operators[3]/fillCS[0]], locationContext=null, errorMessage=null]

My code looks something like this:

try (ByteArrayOutputStream baos = new ByteArrayOutputStream(); PDDocument document = new PDDocument(); COSStream cosStream = new COSStream()) {
    PDPage page = new PDPage();
    document.addPage(page);

    PDDocumentInformation documentInformation = new PDDocumentInformation();
    documentInformation.setTitle("Name");
    documentInformation.setCreator("Creator");
    documentInformation.setSubject("Subject");
    document.setDocumentInformation(documentInformation);

    try (ByteArrayOutputStream xmpOutputStream = new ByteArrayOutputStream(); OutputStream cosXMPStream = cosStream.createOutputStream()) {
        XMPMetadata xmp = XMPMetadata.createXMPMetadata();
        PDFAIdentificationSchema pdfaSchema = xmp.createAndAddPFAIdentificationSchema();
        pdfaSchema.setPart(2);
        pdfaSchema.setConformance("B");
        DublinCoreSchema dublinCoreSchema = xmp.createAndAddDublinCoreSchema();
        dublinCoreSchema.setTitle("Name");
        dublinCoreSchema.addCreator("Creator");
        dublinCoreSchema.setDescription("Subject");
        XMPBasicSchema basicSchema = xmp.createAndAddXMPBasicSchema();
        Calendar creationDate = Calendar.getInstance();
        basicSchema.setCreateDate(creationDate);
        basicSchema.setModifyDate(creationDate);
        basicSchema.setMetadataDate(creationDate);
        basicSchema.setCreatorTool("Creator Tool");
        new XmpSerializer().serialize(xmp, xmpOutputStream, true);
        cosXMPStream.write(xmpOutputStream.toByteArray());
        document.getDocumentCatalog().setMetadata(new PDMetadata(cosStream));
    }

    PDViewerPreferences prefs = new PDViewerPreferences(page.getCOSObject());
    prefs.setDisplayDocTitle(true);
    document.getDocumentCatalog().setViewerPreferences(prefs);

    File fontFile = new File("C:\\Windows\\Fonts\\arial.ttf");
    PDType0Font font = PDType0Font.load(document, fontFile);

    PDPageContentStream contentStream = new PDPageContentStream(document, page);
    contentStream.beginText();
    contentStream.setFont(font, 12);
    contentStream.newLineAtOffset(100, 700);
    contentStream.showText("Hello PDF/A-2b World!");
    contentStream.endText();
    contentStream.close();

    document.save(baos);
    try (PDFAParser parser = Foundries.defaultInstance().createParser(new ByteArrayInputStream(baos.toByteArray()), PDFAFlavour.PDFA_2_B)) {
        PDFAValidator validator = Foundries.defaultInstance().createValidator(PDFAFlavour.PDFA_2_B, false);
        ValidationResult result = validator.validate(parser);
        System.out.println(result.isCompliant());
    }
}

When I inspect the generated PDF with debugger-app-2.0.31.jar, I can find the metadata. When I compare the metadata with a pdf file from the regression test from VeraPDF (eg. this one), the only difference that seems relevant to me is in the begin="" tag. It is empty in the vera test file <?xpacket begin='' and it seems to contain the BOM Start Sequence in the file created by pdfbox <?xpacket begin="".

Is someone able to tell me, if this is an error in VeraPDF or in PDFBox? Is there a solution for this problem? Can someone explain the second error to me and offer an solution?

Solution

  • The CreatePDFA example from the source code does the metadata part slightly differently although yours looks ok (oops no, see update), and I was able to validate it with VeraPDF:

    XmpSerializer serializer = new XmpSerializer();
ByteArrayOutputStream baos = new ByteArrayOutputStream();
serializer.serialize(xmp, baos, true);

PDMetadata metadata = new PDMetadata(doc);
metadata.importXMPMetadata(baos.toByteArray());
doc.getDocumentCatalog().setMetadata(metadata);

    The second problem is the missing output intent. Add this code:

    // sRGB output intent
InputStream colorProfile = CreatePDFA.class.getResourceAsStream(
        "/org/apache/pdfbox/resources/pdfa/sRGB.icc");
PDOutputIntent intent = new PDOutputIntent(doc, colorProfile);
intent.setInfo("sRGB IEC61966-2.1");
intent.setOutputCondition("sRGB IEC61966-2.1");
intent.setOutputConditionIdentifier("sRGB IEC61966-2.1");
intent.setRegistryName("http://www.color.org");
doc.getDocumentCatalog().addOutputIntent(intent);

    About the PDFMergerExample and your original code:

    That example and you used new PDMetadata(cosStream). This constructor doesn't add two mandatory dictionary entries. Add this to your code:

    cosStream.setName(COSName.TYPE, "Metadata");
cosStream.setName(COSName.SUBTYPE, "XML");