iTextSharp：展平表格单元格中的字段会使文本向上移动

Question

我在扁平化表格单元格中生成的字段时遇到问题。我创建了一个示例项目来说明这个问题。

private static void dummyFunction2()
    {
        // Create a PDF with a TextBox in a table cell
        //Get the font ready
        BaseFont bfHelvetica = BaseFont.CreateFont(BaseFont.HELVETICA, BaseFont.CP1250, false);
        var helvetica12 = new Font(bfHelvetica, 12, Font.NORMAL, BaseColor.BLACK);

        //Create the document and filestream
        var doc = new Document(PageSize.LETTER, 18f, 18f, 18f, 18f);
        var fs = new FileStream("TextBoxInTableCell.pdf", FileMode.Create);
        PdfWriter writer = PdfWriter.GetInstance(doc, fs);

        //Create the table
        doc.Open();
        var myTable = new PdfPTable(1);
        myTable.TotalWidth = 568f;
        myTable.LockedWidth = true;
        myTable.HorizontalAlignment = 0;

        //Create the textfield that will sit on a cell in the table
        var tf = new TextField(writer, new Rectangle(67, 585, 140, 800), "cellTextBox");
        tf.Text = "test";
        //Create the table cell
        var tbCell = new PdfPCell(new Phrase(" ", helvetica12));
        //Use fieldpositioningevents to make the field appear on top of the cell
        var events =
            new FieldPositioningEvents(writer, tf.GetTextField());
        tbCell.CellEvent = events;
        //Add the cell to the table
        myTable.AddCell(tbCell);
        PdfContentByte cb = writer.DirectContent;
        //Write out the table to the middle of the document
        myTable.WriteSelectedRows(0, -1, 0, -1, 0, 400, cb);
        doc.Close();
        fs.Close();

        //Open back up the document so that we can set GenerateAppearances to false.
        //This solution proposed and accepted at https://stackoverflow.com/questions/25169342/itextsharp-fields-generated-in-a-table-not-shown-in-adobe-reader
        var reader2 = new PdfReader("TextBoxInTableCell.pdf");
        var stamper2 = new PdfStamper(reader2, new FileStream("tempdoc.pdf", FileMode.Create));
        stamper2.AcroFields.GenerateAppearances = false;
        stamper2.Close();
        reader2.Close();
        Process.Start("tempdoc.pdf");

        //Open the pdf back up
        var reader = new PdfReader("tempdoc.pdf");
        var stamper = new PdfStamper(reader, new FileStream("tempdoc.pdf" + "1.pdf", FileMode.Create));

        //Flatten the form
        stamper.FormFlattening = true;

        //Close everything
        stamper.Close();
        reader.Close();
        Process.Start("tempdoc.pdf" + "1.pdf");
    }

生成的这个未展平的 pdf 看起来像 。如您所见，该字段位于应有的位置。然而，扁平化的 pdf 看起来像 。该字段的文本已明显移动。

我有posted the flattened pdf，以便有人可以在需要时查看 pdf 语言。

我知道这是一个小众问题，但希望有人可以帮助我。

EDIT1：针对 Bruno 的评论，我正在使用从 Nuget 下载的 iTextsharp 5.5.2，可以在here.找到未扁平化的 pdf。

EDIT2：更新了 SO 链接以指向正确的问题。以下是我之前与此问题相关的两个问题供参考：First、Second

Answer 1

Java 版本的 iText 不包含此问题。这是一个 Java -> C# 移植问题。我们会处理的。