''
'' This code is part of Document Solutions for PDF demos.
'' Copyright (c) MESCIUS inc. All rights reserved.
''
Imports System.IO
Imports GrapeCity.Documents.Pdf
Imports GrapeCity.Documents.Pdf.AcroForms

'' This sample shows how to find and remove signature fields from a PDF.
'' The code in this sample is almost identical to the code in RemoveSignatures,
'' which also finds all signature fields, but removes just the signatures,
'' leaving the fields.
'' The PDF used in this sample was created by TimeSheet.
Public Class RemoveSignatureFields
    Public Function CreatePDF(ByVal stream As Stream) As Integer
        Dim doc = New GcPdfDocument()
        Using fs As New FileStream(Path.Combine("Resources", "PDFs", "TimeSheet.pdf"), FileMode.Open, FileAccess.Read)
            doc.Load(fs)

            '' Fields can be children of other fields, so we use
            '' a recursive method to iterate through the whole tree:
            RemoveSignatureFields(doc.AcroForm.Fields)

            '' Done:
            doc.Save(stream)
            Return doc.Pages.Count
        End Using
    End Function

    Sub RemoveSignatureFields(ByVal fields As FieldCollection)
        For i = fields.Count - 1 To 0 Step -1
            RemoveSignatureFields(fields(i).Children)
            If TypeOf fields(i) Is SignatureField Then
                fields.RemoveAt(i)
            End If
        Next
    End Sub
End Class