Not seeing blank signature field added to PDF - itext

Question

I am replacing TextFields to Signature fields and not able to see these blank signature fields in the generated PDF.
These blank fields will be needed to digitally signed by client at later stages.
/// <summary>
/// Adds a text field to the report that the user can update signatures to the specified location.
/// </summary>
/// <param name="writer">pdfwriter of document.</param>
/// <param name="xPosition">The lower left x position of the text field.</param>
/// <param name="yPosition">The lower left y position of the text field.</param>
/// <param name="width">The width of the text field.</param>
/// <param name="height">The height of the text field.</param>
/// <param name="fieldId"></param>
protected virtual void AddTextField(iTextSharp.text.pdf.PdfWriter writer, String fieldId, float xPosition, float yPosition, float width, float height)
{
Rectangle position = new Rectangle(xPosition, yPosition, xPosition + width, Math.Max(yPosition - height, 0));
iTextSharp.text.pdf.TextField field = new iTextSharp.text.pdf.TextField(writer, position, fieldId);
// Requirement is to change existing textFields to blank Signature fields
// In the method, memoryStream, reader and stamper are not available.
// Below is the textField I need to transform into Signature field.
// field.Text = String.Empty;
// field.Font = FontFactory.GetFont("Arial Narrow").BaseFont;
// field.TextColor = Color.WHITE;
// field.FontSize = 9;
// Not seeing the signature field appear on the pdf.
// Don't know exactly the reason
PdfFormField sig = PdfFormField.CreateSignature(writer);
sig.SetWidget(position, null);
sig.Flags = PdfAnnotation.FLAGS_PRINT;
sig.Put(PdfName.DA, new PdfString("/Helv 0 Tf 0 g"));
sig.FieldName = fieldId;
sig.SetPage();
writer.AddAnnotation(sig);
//Also tried below code
//PdfFormField pfield = PdfFormField.CreateSignature(writer);
//pfield.FieldName = fieldId;
//pfield.SetFieldFlags(PdfAnnotation.FLAGS_PRINT);
//pfield.SetWidget(position, null);
//pfield.SetPage();
//pfield.MKBorderColor = Color.BLACK;
//pfield.MKBackgroundColor = Color.BLUE;
//PdfAppearance tp = PdfAppearance.CreateAppearance(writer, width, height);
//tp.Rectangle(position);
//tp.Stroke();
//pfield.SetAppearance(PdfAnnotation.APPEARANCE_NORMAL, tp);
//writer.AddAnnotation(pfield);
}
Second quest:
*Do I really need a signature field if - client will add signature text to these field at later stages (using 3rd party tool like DocuSign)? or simple PDFTextFields would really work?
Adding above question with the query as this may be helpful in relating my scenario.
Thanks in advance for the help.

Answer 1

I just tested your code using
public void AddSignatureFieldLikePrashantJha()
{
Document document = new Document();
Stream stream = new FileStream(#"emptySignatureFieldLikePrashantJha.pdf", FileMode.Create);
PdfWriter pdfWriter = PdfWriter.GetInstance(document, stream);
document.Open();
AddTextField(pdfWriter, "Signature", 100, 100, 400, 50);
document.Close();
}
In the result Adobe Reader DC clearly indicated the signature field position by an arrow:
Putting the focus to that field (e.g. by pressing TAB) the field even is given a frame:
Earlier Adobe Reader versions show it even clearer, e.g. 9.5:
Thus, I cannot reproduce that you are
not able to see these blank signature fields in the generated PDF
If you want to have the field area appear somehow more pronounced, you can indeed use a PdfAppearance, e.g.
protected virtual void AddFancySignatureField(iTextSharp.text.pdf.PdfWriter writer, String fieldId, float xPosition, float yPosition, float width, float height)
{
Rectangle position = new Rectangle(xPosition, yPosition, xPosition + width, Math.Max(yPosition - height, 0));
iTextSharp.text.pdf.TextField field = new iTextSharp.text.pdf.TextField(writer, position, fieldId);
PdfFormField sig = PdfFormField.CreateSignature(writer);
sig.SetWidget(position, null);
sig.Flags = PdfAnnotation.FLAGS_PRINT;
sig.Put(PdfName.DA, new PdfString("/Helv 0 Tf 0 g"));
sig.FieldName = fieldId;
sig.SetPage();
PdfAppearance tp = PdfAppearance.CreateAppearance(writer, width, height);
PdfShading radial = PdfShading.SimpleRadial(writer, 0, height / 2, 0, 0, height / 2, width, BaseColor.RED, BaseColor.GREEN);
tp.PaintShading(radial);
sig.SetAppearance(PdfAnnotation.APPEARANCE_NORMAL, tp);
writer.AddAnnotation(sig);
}
The result looks like this:
Second quest: *Do I really need a signature field if - client will add signature text to these field at later stages (using 3rd party tool like DocuSign)? or simple PDFTextFields would really work?
That depends very much on the exact 3rd party tool used. Some such tools require signature fields, some require a text marker in the content, some want the position given by coordinate...