Itext7 Hebrew reverse issue

The only solution that I have found with iText7 and IBM ICU4J without any other third party libraries is to first render the lines and then mirror them one by one. This requires a helper class LineMirroring and it's not precisely the most elegant solution, but will produce the output that you expect.

Lines mirroring class:

public class LineMirroring {

private final PageSize pageSize;
private final String fontName;
private final int fontSize;

public LineMirroring(PageSize pageSize, String fontName, int fontSize) {
    this.pageSize = pageSize;
    this.fontName = fontName;
    this.fontSize = fontSize;
}

public String mirrorParagraph(String input, int height, int width, Border border) {
    final StringBuilder mirrored = new StringBuilder();
    try (ByteArrayOutputStream output = new ByteArrayOutputStream()) {
        PdfFont font = PdfFontFactory.createRegisteredFont(fontName, PdfEncodings.IDENTITY_H, true);
        final PdfWriter writer = new PdfWriter(output);
        final PdfDocument pdfDoc = new PdfDocument(writer);
        pdfDoc.setDefaultPageSize(pageSize);
        pdfDoc.addFont(font);
        final Document doc = new Document(pdfDoc);
        doc.setBaseDirection(BaseDirection.RIGHT_TO_LEFT);
        final LineTrackingParagraph paragraph = new LineTrackingParagraph(input);
        paragraph.setFont(font)
                .setFontSize(fontSize)
                .setTextAlignment(TextAlignment.RIGHT)
                .setHeight(height)
                .setWidth(width)
                .setBorder(border);
        LineTrackingParagraphRenderer renderer = new LineTrackingParagraphRenderer(paragraph);
        doc.add(paragraph);
        Bidi bidi;
        for (LineRenderer lr : paragraph.getWrittenLines()) {
            bidi = new Bidi(((TextRenderer) lr.getChildRenderers().get(0)).getText().toString(), Bidi.RTL);
            mirrored.append(bidi.writeReordered(Bidi.DO_MIRRORING));
        }
        doc.close();
        pdfDoc.close();
        writer.close();
    } catch (IOException ioe) {
        ioe.printStackTrace();
    }
    return mirrored.toString();
}

private class LineTrackingParagraph extends Paragraph {

    private List<LineRenderer> lines;

    public LineTrackingParagraph(String text) {
        super(text);
    }

    public void addWrittenLines(List<LineRenderer> lines) {
        this.lines = lines;
    }

    public List<LineRenderer> getWrittenLines() {
        return lines;
    }

    @Override
    protected IRenderer makeNewRenderer() {
        return new LineTrackingParagraphRenderer(this);
    }
}

private class LineTrackingParagraphRenderer extends ParagraphRenderer {
    public LineTrackingParagraphRenderer(LineTrackingParagraph modelElement) {
        super(modelElement);
    }

    @Override
    public void drawChildren(DrawContext drawContext) {
        ((LineTrackingParagraph)modelElement).addWrittenLines(lines);
        super.drawChildren(drawContext);
    }

    @Override
    public IRenderer getNextRenderer() {
        return new LineTrackingParagraphRenderer((LineTrackingParagraph) modelElement);
    }
}

}

Minimal JUnit Test:

public class Itext7HebrewTest {

@Test
public void generatePdf() {

    final SimpleDateFormat formatter = new SimpleDateFormat("yyyy-MM-dd-hh.mm.ss");
    final String dest = "F:\\Temp\\" + formatter.format(Calendar.getInstance().getTime()) + ".pdf";
    final String fontPath = "C:\\Windows\\Fonts\\ARIALUNI.TTF";
    final String fontName = "arialUnicode";
    FontProgramFactory.registerFont(fontPath, "arialUnicode");

    try (ByteArrayOutputStream output = new ByteArrayOutputStream()) {
        PdfFont arial = PdfFontFactory.createRegisteredFont(fontName, PdfEncodings.IDENTITY_H, true);

        PdfDocument pdfDoc = new PdfDocument(new PdfWriter(output));
        pdfDoc.setDefaultPageSize(PageSize.A4);
        pdfDoc.addFont(arial);
        LineMirroring mirroring = new LineMirroring(pdfDoc.getDefaultPageSize(), fontName,9);

        Document doc = new Document(pdfDoc);
        doc.setBaseDirection(BaseDirection.RIGHT_TO_LEFT);

        final String txt = "בתשרי נתן הדקל פרי שחום נחמד בחשוון ירד יורה ועל גגי רקד בכסלו נרקיס הופיע בטבת ברד ובשבט חמה הפציעה ליום אחד.  1234 באדר עלה ניחוח מן הפרדסים בניסן הונפו בכוח כל החרמשים";

        final int height = 200;
        final int width = 70;
        final Border border = new SolidBorder(3);

        Paragraph paragraph1 = new Paragraph(mirroring.mirrorParagraph(txt, height, width, border));
        paragraph1.setFont(arial)
                .setFontSize(9)
                .setTextAlignment(TextAlignment.RIGHT)
                .setHeight(height)
                .setWidth(width)
                .setBorder(border);
        doc.add(paragraph1);

        doc.close();
        doc.flush();
        try (FileOutputStream pdfFile = new FileOutputStream(dest)) {
            pdfFile.write(output.toByteArray());
        }
    } catch (Exception e) {
        e.printStackTrace();
    }
}

}