How to continue field output on a second page?

I have generated a PDF from a template. The PDF has a field in the middle of it that is of variable length. I am trying to work it so that if the field's content overflows, then the program will use a second instance template as a second page and continue in the same field there. Is this possible?

Posted on StackOverflow on Nov 10, 2014 by Carlos Mendieta

This will only work if you flatten the form. I've written a proof of concept, AddExtraPage, where I have a PDF form src that has a field named "body":

public void manipulatePdf(String src, String dest)
    throws DocumentException, IOException {
    PdfReader reader = new PdfReader(src);
    Rectangle pagesize = reader.getPageSize(1);
    PdfStamper stamper = new PdfStamper(reader, new FileOutputStream(dest));
    Paragraph p = new Paragraph();
    p.add(new Chunk("Hello "));
    p.add(new Chunk("World", new Font(FontFamily.HELVETICA, 12, Font.BOLD)));
    AcroFields form = stamper.getAcroFields();
    Rectangle rect = form.getFieldPositions("body").get(0).position;
    int status;
    PdfImportedPage newPage = null;
    ColumnText column = new ColumnText(stamper.getOverContent(1));
    column.setSimpleColumn(rect);
    int pagecount = 1;
    for (int i = 0; i < 100; ) {
        i++;
        column.addElement(new Paragraph("Hello " + i));
        column.addElement(p);
        status = column.go();
        if (ColumnText.hasMoreText(status)) {
            newPage = loadPage(newPage, reader, stamper);
            triggerNewPage(stamper, pagesize, newPage, column,
                rect, ++pagecount);
        }
    }
    stamper.setFormFlattening(true);
    stamper.close();
    reader.close();
}
 
public PdfImportedPage loadPage(
    PdfImportedPage page, PdfReader reader, PdfStamper stamper) {
    if (page == null) {
        return stamper.getImportedPage(reader, 1);
    }
    return page;
}
 
public void triggerNewPage(PdfStamper stamper, Rectangle pagesize,
    PdfImportedPage page, ColumnText column, Rectangle rect, int pagecount)
    throws DocumentException {
    stamper.insertPage(pagecount, pagesize);
    PdfContentByte canvas = stamper.getOverContent(pagecount);
    canvas.addTemplate(page, 0, 0);
    column.setCanvas(canvas);
    column.setSimpleColumn(rect);
    column.go();
}

As you can see, we create a PdfImportedPage instance and we insert a new page with this page as background. We add the content at the position defined by the field using ColumnText.

Click this link if you want to see how to answer this question in iText 7.