PDFBox 3.0.2: Das Image für die Zugänglichkeit kann nicht ordnungsgemäß markiert werden ⇐ Java

[Guest]

Ich versuche, ein PDF -Dokument mit besserer Zugänglichkeit zu erstellen. Es muss keine Standards übergeben, aber ich möchte Bildern Alt -Text hinzufügen. Ich kann Text richtig markieren, aber ich kann bei Verwendung eines ähnlichen Workflows keine Bilder richtig markieren. Ich habe diesen Beitrag und seinen zugehörigen Beitrag verwiesen, um meinen aktuellen Code zu erstellen.

Code: Select all

public static void main(String[] args) throws IOException {
int mcidCounter = 0;
int structParentCounter = 0;
PDDocument document = new PDDocument();
PDPage page = new PDPage(PDRectangle.A4);
document.addPage(page);

page.setStructParents(structParentCounter);

PDPageContentStream contentStream = null;
try {
contentStream = new PDPageContentStream(document, page);
} catch (IOException e) {
throw new RuntimeException(e);
}

PDImageXObject pdImage = PDImageXObject.createFromFile("image_file", document);

PDDocumentCatalog catalog = document.getDocumentCatalog();
PDStructureTreeRoot structureTreeRoot = new PDStructureTreeRoot();
catalog.setStructureTreeRoot(structureTreeRoot);

PDViewerPreferences prefs = new PDViewerPreferences(new COSDictionary());
prefs.setDisplayDocTitle(true);
catalog.setViewerPreferences(prefs);

PDMarkInfo markInfo = new PDMarkInfo();
markInfo.setMarked(true);
catalog.setMarkInfo(markInfo);

PDStructureElement documentElement = new PDStructureElement(StandardStructureTypes.DOCUMENT, structureTreeRoot);
structureTreeRoot.appendKid(documentElement);

PDStructureElement paragraphElement = new PDStructureElement(StandardStructureTypes.P, documentElement);
paragraphElement.setPage(page);
documentElement.appendKid(paragraphElement);

COSDictionary markedContentDictionary = new COSDictionary();
markedContentDictionary.setInt(COSName.MCID, mcidCounter);

PDMarkedContentReference mcr = new PDMarkedContentReference();
mcr.setMCID(mcidCounter);
paragraphElement.appendKid(mcr);

contentStream.beginMarkedContent(COSName.P, PDPropertyList.create(markedContentDictionary));
contentStream.setFont(new PDType1Font(Standard14Fonts.FontName.HELVETICA_BOLD), 12);
contentStream.beginText();
contentStream.newLineAtOffset(50, 700);
contentStream.showText("Document Title");
contentStream.endText();
contentStream.endMarkedContent();

PDStructureElement figureElement = new PDStructureElement(StandardStructureTypes.Figure, documentElement);
figureElement.setPage(page);
figureElement.setAlternateDescription("Alternate Image Description");
documentElement.appendKid(figureElement);

COSDictionary markedContentDictionary3 = new COSDictionary();
markedContentDictionary3.setInt(COSName.MCID, mcidCounter + 2);
markedContentDictionary3.setString(COSName.ALT, "Alternate Image Description");

PDMarkedContentReference mcr3 = new PDMarkedContentReference();
mcr3.setMCID(mcidCounter + 2);
figureElement.appendKid(mcr3);

contentStream.beginMarkedContent(COSName.IMAGE, PDPropertyList.create(markedContentDictionary3));
contentStream.drawImage(pdImage, 50, 0);
contentStream.endMarkedContent();

contentStream.close();

COSDictionary parentTreeRoot = new COSDictionary();
PDNumberTreeNode parentTree = new PDNumberTreeNode(parentTreeRoot, COSBase.class);

Map parentTreeMap = new HashMap();
parentTreeMap.put(structParentCounter, paragraphElement);
parentTree.setNumbers(parentTreeMap);
structureTreeRoot.setParentTree(parentTree);

ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
document.save(outputStream);

byte[] pdfBytes = outputStream.toByteArray();
document.close();

Path actualPath = Path.of("test.pdf");
Files.write(actualPath, pdfBytes, StandardOpenOption.CREATE, StandardOpenOption.WRITE);
}

Dies ist die interne Struktur der PDF
. Ich sollte sehen?