How to make PDF text selectable using Apache PDFBox?

Question

I am trying to make text selectable at PDF reading application made on JavaFX. I have PDF files that contain screenshots with text and OCR layer. So I need the text to be selectable like at regular viewer. I set up getting image from page and now trying to figure out how to highlight text.

I tried following:

    InputStream is = this.getClass().getResourceAsStream(currentPdf);
    Image convertedImage;
    try {
        PDDocument document = PDDocument.load(is);
        List<PDPage> list = document.getDocumentCatalog().getAllPages();
        PDPage page = list.get(pageNum);
        List annotations = page.getAnnotations();
        PDAnnotationTextMarkup markup = new PDAnnotationTextMarkup(PDAnnotationTextMarkup.SUB_TYPE_HIGHLIGHT);
        markup.setRectangle(new PDRectangle(600, 600));
        markup.setQuadPoints(new float[]{100, 100, 200, 100, 100, 500, 200, 500});
        annotations.add(markup);
        page.setAnnotations(annotations);
        BufferedImage image = page.convertToImage(BufferedImage.TYPE_INT_RGB, 128);
        convertedImage = SwingFXUtils.toFXImage(image, null);
        document.close();
        imageView.setImage(convertedImage);
    } catch (Exception e) {
        throw new RuntimeException(e);
    }

but that results in image without any highlights.

I also tried to find information at stack overflow or other resources, but haven't found anything.

Would appreciate some Java code sample which enables text highlighting with mouse.

Answer 1

I used ICEpdf and did the following:

question.getSelectedBounds()
                .stream()
                .map(Shape::getBounds)
                .forEach(bounds -> {
                    SquareAnnotation squareAnnotation = (SquareAnnotation)
                            AnnotationFactory.buildAnnotation(
                                    pdfController.getPageTree().getLibrary(),
                                    Annotation.SUBTYPE_SQUARE,
                                    bounds);
                    squareAnnotation.setFillColor(true);
                    squareAnnotation.setFillColor(new Color(255, 250, 57, 120));
                    squareAnnotation.setRectangle(bounds);
                    squareAnnotation.setBBox(bounds);
                    squareAnnotation.resetAppearanceStream(null);
                    AbstractAnnotationComponent annotationComponent = AnnotationComponentFactory
                            .buildAnnotationComponent(squareAnnotation, pdfController.getDocumentViewController(),
                                    pageViewComponent, pdfController.getDocumentViewController().getDocumentViewModel());
                    pageViewComponent.addAnnotation(annotationComponent);
                });