PDF Interactive Forms (AcroForms) in VB

'---------------------------------------------------------------------------------------
' Copyright (c) 2001-2019 by PDFTron Systems Inc. All Rights Reserved.
' Consult legal.txt regarding legal and license information.
'---------------------------------------------------------------------------------------

Imports System

Imports pdftron
Imports pdftron.Common
Imports pdftron.Filters
Imports pdftron.SDF
Imports pdftron.PDF

'---------------------------------------------------------------------------------------
' This sample illustrates basic PDFNet capabilities related to interactive 
' forms (also known as AcroForms). 
'---------------------------------------------------------------------------------------
Module InteractiveFormsTestVB
	Dim pdfNetLoader As PDFNetLoader
	Sub New()
		pdfNetLoader = pdftron.PDFNetLoader.Instance()
	End Sub

	Sub Main()

		PDFNet.Initialize()

		' Relative path to the folder containing test files.
		' Dim input_path As String = "../../../../TestFiles/"
		Dim output_path As String = "../../../../TestFiles/Output/"

		Try
			'----------------------------------------------------------------------------------
			' Example 1: Programatically create new Form Fields and Widget Annotations.
			'----------------------------------------------------------------------------------
			Using doc As PDFDoc = New PDFDoc
				Dim blank_page As Page = doc.PageCreate()		  ' Create a blank page and some new fields (aka "AcroForms").

				' Create new fields.
				Dim emp_first_name As Field = doc.FieldCreate("employee.name.first", _
				 Field.Type.e_text, doc.CreateIndirectString("John"))
				Dim emp_last_name As Field = doc.FieldCreate("employee.name.last", _
				 Field.Type.e_text, doc.CreateIndirectString("Doe"))
				Dim emp_last_check1 As Field = doc.FieldCreate("employee.name.check1", _
				 Field.Type.e_check, doc.CreateIndirectName("Yes"))
				Dim submit As Field = doc.FieldCreate("submit", _
				 Field.Type.e_button)

				' Create page annotations for the above fields.
				Dim sdfdoc As SDFDoc = doc.GetSDFDoc()

				' Create text annotations
				Dim annot1 As pdftron.PDF.Annots.Widget = pdftron.PDF.Annots.Widget.Create(sdfdoc, New Rect(50, 550, 350, 600), emp_first_name)
				Dim annot2 As pdftron.PDF.Annots.Widget = pdftron.PDF.Annots.Widget.Create(sdfdoc, New Rect(50, 450, 350, 500), emp_last_name)

				' Create check-box annotation
				Dim annot3 As pdftron.PDF.Annots.Widget = pdftron.PDF.Annots.Widget.Create(sdfdoc, New Rect(64, 356, 120, 410), emp_last_check1)

				' Set the annotation appearance for the "Yes" state...
				annot3.SetAppearance(CreateCheckmarkAppearance(doc), Annot.AnnotationState.e_normal, "Yes")

				' Create button annotation
				Dim annot4 As pdftron.PDF.Annots.Widget = pdftron.PDF.Annots.Widget.Create(sdfdoc, New Rect(64, 284, 163, 320), submit)
				' Set the annotation appearances for the down and up state...
				annot4.SetAppearance(CreateButtonAppearance(doc, False), Annot.AnnotationState.e_normal)
				annot4.SetAppearance(CreateButtonAppearance(doc, True), Annot.AnnotationState.e_down)

				' Create 'SubmitForm' action. The action will be linked to the button.
				Dim url As FileSpec = FileSpec.CreateURL(sdfdoc, "http://www.pdftron.com")
				Dim button_action As pdftron.PDF.Action = pdftron.PDF.Action.CreateSubmitForm(url)

				' Associate the above action with 'Down' event in annotations action dictionary.
				Dim annot_action As Obj = annot4.GetSDFObj().PutDict("AA")
				annot_action.Put("D", button_action.GetSDFObj())

				blank_page.AnnotPushBack(annot1)			  ' Add annotations to the page
				blank_page.AnnotPushBack(annot2)
				blank_page.AnnotPushBack(annot3)
				blank_page.AnnotPushBack(annot4)

				doc.PagePushBack(blank_page)			 ' Add the page as the last page in the document.

				' If you are not satisfied with the look of default auto-generated appearance 
				' streams you can delete "AP" entry from the Widget annotation and set 
				' "NeedAppearances" flag in AcroForm dictionary:
				'    doc.GetAcroForm().PutBool("NeedAppearances", true)
				'    			
				' This will force the viewer application to auto-generate new appearance streams 
				' every time the document is opened.
				'
				' Alternatively you can generate custom annotation appearance using ElementWriter 
				' and then set the "AP" entry in the widget dictionary to the new appearance
				' stream.
				'
				' Yet another option is to pre-populate field entries with dummy text. When 
				' you edit the field values using PDFNet the new field appearances will match 
				' the old ones.
				doc.RefreshFieldAppearances()

				doc.Save(output_path + "forms_test1.pdf", 0)
			End Using
			Console.WriteLine("Done. Result saved in forms_test1.pdf")

			'----------------------------------------------------------------------------------
			' Example 2: 
			' Fill-in forms / Modify values of existing fields.
			' Traverse all form fields in the document (and print out their names). 
			' Search for specific fields in the document.
			'----------------------------------------------------------------------------------
			Using doc4 As PDFDoc = New PDFDoc(output_path + "forms_test1.pdf")
				doc4.InitSecurityHandler()

				Dim itr As FieldIterator = doc4.GetFieldIterator()
				While itr.HasNext()
					Console.WriteLine("Field name: {0}", itr.Current().GetName())
					Console.WriteLine("Field partial name: {0}", itr.Current().GetPartialName())
					Console.Write("Field type: ")

					Dim field As Field = itr.Current()
					Dim type As Field.Type = field.GetType()

					If type = field.Type.e_button Then
						Console.WriteLine("Button")
					ElseIf type = field.Type.e_radio Then
						Console.WriteLine("Radio button")
					ElseIf type = field.Type.e_check Then
						Console.WriteLine("Check box")
						field.SetValue(True)
					ElseIf type = field.Type.e_text Then
						Console.WriteLine("Text")

						' Edit all variable text in the document
						Dim old_value As String = "none"
						If Not field.GetValue() Is Nothing Then
							old_value = field.GetValueAsString()
						End If
						field.SetValue("This is a new value. The old one was: " + old_value)
					ElseIf type = field.Type.e_choice Then
						Console.WriteLine("Choice")
					ElseIf type = field.Type.e_signature Then
						Console.WriteLine("Signature")
					End If

					Console.WriteLine("------------------------------")
					itr.Next()
				End While

				' Search for a specific field
				Dim fld As Field = doc4.GetField("employee.name.first")
				If Not fld Is Nothing Then
					Console.WriteLine("Field search for {0} was successful: ", fld.GetName(), fld.GetValueAsString())
				Else
					Console.WriteLine("Field search failed.")
				End If

				' Regenerate field appearances.
				doc4.RefreshFieldAppearances()

				doc4.Save(output_path + "forms_test_edit.pdf", 0)
			End Using
			Console.WriteLine("Done. Results saved in forms_test_edit.pdf")

			'----------------------------------------------------------------------------------
			' Sample: Form templating
			' Replicate pages and form data within a document. Then rename field names to make 
			' them unique.
			'----------------------------------------------------------------------------------
			Using doc3 As PDFDoc = New PDFDoc(output_path + "forms_test1.pdf")
				doc3.InitSecurityHandler()

				Dim src_page3 As Page = doc3.GetPage(1)
				doc3.PagePushBack(src_page3)	 ' Append several copies of the second page
				doc3.PagePushBack(src_page3)	 ' Note that forms are successfully copied
				doc3.PagePushBack(src_page3)

				' Now we rename fields in order to make every field unique.
				' You can use this technique for dynamic template filling where you have a 'master'
				' form page that should be replicated, but with unique field names on every page. 
				RenameAllFields(doc3, "employee.name.first")
				RenameAllFields(doc3, "employee.name.last")
				RenameAllFields(doc3, "employee.name.check1")
				RenameAllFields(doc3, "submit")

				doc3.RefreshFieldAppearances()

				doc3.Save(output_path + "forms_test1_cloned.pdf", 0)
			End Using
			Console.WriteLine("Done. Results saved in forms_test1_cloned.pdf")

			'----------------------------------------------------------------------------------
			' Sample: 
			' Flatten all form fields in a document.
			' Note that this sample is intended to show that it is possible to flatten
			' individual fields. PDFNet provides a utility function PDFDoc.FlattenAnnotations()
			' that will automatically flatten all fields.
			'----------------------------------------------------------------------------------
			Using doc5 As PDFDoc = New PDFDoc(output_path + "forms_test1.pdf")
				doc5.InitSecurityHandler()

				Dim autoflat As Boolean = True
				If (autoflat) Then
					doc5.FlattenAnnotations()
				Else	' Manual flattening
					Dim pitr As PageIterator = doc5.GetPageIterator()
					While pitr.HasNext()
						Dim page As Page = pitr.Current()
						Dim annots As Obj = page.GetAnnots()
						If Not annots Is Nothing Then
							' Look for all widget annotations (in reverse order)
							Dim i As Integer = annots.Size() - 1
							While i >= 0
								Dim subtype As String = annots.GetAt(i).Get("Subtype").Value().GetName()
								If subtype.Equals("Widget") Then
									Dim field As Field = New Field(annots.GetAt(i))
									field.Flatten(page)
									' Another way of making a read only field is by modifying 
									' field's e_read_only flag: 
									' field.SetFlag(Field.FieldFlag.e_read_only, true)
								End If
								i = i - 1
							End While
						End If
						pitr.Next()
					End While
				End If


				doc5.Save(output_path + "forms_test1_flattened.pdf", 0)
			End Using
			Console.WriteLine("Done. forms_test1_flattened.pdf")

		Catch ex As PDFNetException
			Console.WriteLine(ex.Message)
		Catch ex As Exception
			MsgBox(ex.Message)
		End Try

	End Sub

	Sub RenameAllFields(ByRef d As PDFDoc, ByVal name As String)
		Dim fld As Field = d.GetField(name)
		Dim counter As Integer = 0
		While Not fld Is Nothing
			fld.Rename(name + counter.ToString())
			fld = d.GetField(name)
			counter = counter + 1
		End While
	End Sub

	Function CreateCheckmarkAppearance(ByRef doc As PDFDoc) As Obj
		' Create a checkmark appearance stream ------------------------------------
		Dim builder As ElementBuilder = New ElementBuilder
		Dim writer As ElementWriter = New ElementWriter

		writer.Begin(doc.GetSDFDoc())
		writer.WriteElement(builder.CreateTextBegin())

		' other options are circle ("l"), diamond ("H"), cross ("\x35")
		' See section D.4 "ZapfDingbats Set and Encoding" in PDF Reference Manual for 
		' the complete graphical map for ZapfDingbats font.
		Dim checkmark As Element = builder.CreateTextRun("4", Font.Create(doc, Font.StandardType1Font.e_zapf_dingbats), 1)
		writer.WriteElement(checkmark)

		writer.WriteElement(builder.CreateTextEnd())

		Dim stm As Obj = writer.End()

		' Calling Dispose() on ElementReader/Writer/Builder can result in increased performance and lower memory consumption.
		writer.Dispose()
		builder.Dispose()

		' Set the bounding box
		stm.PutRect("BBox", -0.2, -0.2, 1, 1)
		stm.PutName("Subtype", "Form")
		Return stm
	End Function

	Function CreateButtonAppearance(ByRef doc As PDFDoc, ByVal button_down As Boolean) As Obj
		' Create a button appearance stream ------------------------------------
		Dim builder As ElementBuilder = New ElementBuilder
		Dim writer As ElementWriter = New ElementWriter

		writer.Begin(doc.GetSDFDoc())

		' Draw background
		Dim element As Element = builder.CreateRect(0, 0, 101, 37)
		element.SetPathFill(True)
		element.SetPathStroke(False)
		element.GetGState().SetFillColorSpace(ColorSpace.CreateDeviceGray())
		element.GetGState().SetFillColor(New ColorPt(0.75, 0, 0))
		writer.WriteElement(element)

		' Draw 'Submit' text
		writer.WriteElement(builder.CreateTextBegin())

		element = builder.CreateTextRun("Submit", Font.Create(doc, Font.StandardType1Font.e_helvetica_bold), 12)
		element.GetGState().SetFillColor(New ColorPt(0, 0, 0))

		If (button_down) Then
			element.SetTextMatrix(1, 0, 0, 1, 33, 10)
		Else
			element.SetTextMatrix(1, 0, 0, 1, 30, 13)
		End If

		writer.WriteElement(element)
		writer.WriteElement(builder.CreateTextEnd())

		Dim stm As Obj = writer.End()

		' Calling Dispose() on ElementReader/Writer/Builder can result in increased performance and lower memory consumption.
		writer.Dispose()
		builder.Dispose()

		' Set the bounding box
		stm.PutRect("BBox", 0, 0, 101, 37)
		stm.PutName("Subtype", "Form")
		Return stm
	End Function

End Module