TimeSheetIncremental.vb
''
'' This code is part of GrapeCity Documents for PDF samples.
'' Copyright (c) GrapeCity, Inc. All rights reserved.
''
Imports System.IO
Imports System.Drawing
Imports GrapeCity.Documents.Pdf
Imports GrapeCity.Documents.Pdf.AcroForms
Imports GrapeCity.Documents.Text
Imports GrapeCity.Documents.Common
Imports GrapeCity.Documents.Drawing
Imports GrapeCity.Documents.Pdf.Security
Imports System.Security.Cryptography.X509Certificates

'' This sample is almost the same as TimeSheet, with one significant difference:
'' unlike the other sample, in this one the filled form is digitally signed by
'' the employee, and the signed PDF is signed again by the supervisor using
'' incremental update (the only way to sign an already signed PDF while
'' preserving the validity of the first signature).
''
'' NOTE: if you download this sample and run it locally on your own system,
'' you will need to have a valid license for it to work as expected, because
'' in an unlicensed version the automatically added nag page caption will
'' invalidate the employee's signature.
Public Class TimeSheetIncremental
    '' Font collection to hold the fonts we need:
    Private _fc As FontCollection = New FontCollection()
    '' The text layout used to render input fields when flattening the document:
    Private _inputTl As TextLayout = New TextLayout()
    '' The text format used for input fields:
    Private _inputTf As TextFormat = New TextFormat()
    '' Input fields margin:
    Private _inputMargin As Single = 5
    '' Space for employee's signature:
    Private _empSignRect As RectangleF
    ''
    Private _logo As Image


    '' Main entry point of this sample:
    Function CreatePDF(ByVal stream As Stream) As Integer
        '' Set up a font collection with the fonts we need:
        _fc.RegisterDirectory(Path.Combine("Resources", "Fonts"))
        '' Set that font collection on input fields' text layout
        '' (we will also set it on all text layouts that we'll use):
        _inputTl.FontCollection = _fc
        '' Set up layout and formatting for input fields:
        _inputTl.ParagraphAlignment = ParagraphAlignment.Center
        _inputTf.FontName = "Segoe UI"
        _inputTf.FontSize = 12
        _inputTf.FontBold = True

        '' Create the time sheet input form
        '' (in a real-life scenario, we probably would only create it once,
        '' And then re-use the form PDF):
        Dim doc = MakeTimeSheetForm()

        '' At this point, 'doc' is an empty AcroForm.
        '' In a real-life app it would be distributed to employees
        '' for them to fill and send back.
        Using empSignedStream = FillEmployeeData(doc)
            '' At this point 'empSignedStream' contains the form filled with employee's data and signed by them.
            ''

            '' Load the employee-signed document
            doc.Load(empSignedStream)

            '' Fill in supervisor data
            Dim supName = "Jane Donahue"
            Dim supSignDate = DateTime.Now.ToShortDateString()
            SetFieldValue(doc, _Names.EmpSuper, supName)
            SetFieldValue(doc, _Names.SupSignDate, supSignDate)

            '' Digitally sign the document on behalf of the supervisor
            Dim pfxPath = Path.Combine("Resources", "Misc", "GcPdfTest.pfx")
            Dim cert = New X509Certificate2(File.ReadAllBytes(pfxPath), "qq",
                    X509KeyStorageFlags.MachineKeySet Or X509KeyStorageFlags.PersistKeySet Or X509KeyStorageFlags.Exportable)
            '' Connect the signature field And signature props
            Dim sp = New SignatureProperties() With {
                .Certificate = cert,
                .Location = "GcPdfWeb - TimeSheet Incremental",
                .SignerName = supName,
                .SignatureDigestAlgorithm = SignatureDigestAlgorithm.SHA512,
                .SignatureField = DirectCast(doc.AcroForm.Fields.First(Function(f_) f_.Name = _Names.SupSign), SignatureField)
            }

            '' Any changes to the document would invalidate the employee's signature, so we cannot do this:
            '' supSign.Widget.ButtonAppearance.Caption = supName;
            ''
            '' Done, now save the document with supervisor signature
            '' NOTE in order to Not invalidate the employee's signature,
            '' we MUST use incremental update here (which Is true by default in Sign() method)
            doc.Sign(sp, stream)
        End Using
        _logo.Dispose()
        Return doc.Pages.Count
    End Function

    '' Replaces any text fields in the document with regular text,
    '' except fields listed in 'excludeFields':
    Private Sub FlattenDoc(ByVal doc As GcPdfDocument, ParamArray excludeFields As String())
        For Each f In doc.AcroForm.Fields
            If TypeOf f Is TextField AndAlso Not excludeFields.Contains(f.Name) Then
                Dim fld = DirectCast(f, TextField)
                Dim w = fld.Widget
                Dim g = w.Page.Graphics
                _inputTl.Clear()
                _inputTl.Append(fld.Value, _inputTf)
                _inputTl.MaxHeight = w.Rect.Height
                _inputTl.PerformLayout(True)
                g.DrawTextLayout(_inputTl, w.Rect.Location)
            End If
        Next
        For i = doc.AcroForm.Fields.Count - 1 To 0 Step -1
            If TypeOf doc.AcroForm.Fields(i) Is TextField AndAlso Not excludeFields.Contains(doc.AcroForm.Fields(i).Name) Then
                doc.AcroForm.Fields.RemoveAt(i)
            End If
        Next
    End Sub

    '' Data field names:
    Private Structure _Names
        Shared ReadOnly Dows As String() = {
            "Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"
        }
        Const EmpName = "empName"
        Const EmpTitle = "empTitle"
        Const EmpNum = "empNum"
        Const EmpStatus = "empStatus"
        Const EmpDep = "empDep"
        Const EmpSuper = "empSuper"
        Shared ReadOnly DtNames = New Dictionary(Of String, String()) From {
            {"Sun", New String() {"dtSun", "tSunStart", "tSunEnd", "tSunReg", "tSunOvr", "tSunTotal"}},
            {"Mon", New String() {"dtMon", "tMonStart", "tMonEnd", "tMonReg", "tMonOvr", "tMonTotal"}},
            {"Tue", New String() {"dtTue", "tTueStart", "tTueEnd", "tTueReg", "tTueOvr", "tTueTotal"}},
            {"Wed", New String() {"dtWed", "tWedStart", "tWedEnd", "tWedReg", "tWedOvr", "tWedTotal"}},
            {"Thu", New String() {"dtThu", "tThuStart", "tThuEnd", "tThuReg", "tThuOvr", "tThuTotal"}},
            {"Fri", New String() {"dtFri", "tFriStart", "tFriEnd", "tFriReg", "tFriOvr", "tFriTotal"}},
            {"Sat", New String() {"dtSat", "tSatStart", "tSatEnd", "tSatReg", "tSatOvr", "tSatTotal"}}
        }
        Const TotalReg = "totReg"
        Const TotalOvr = "totOvr"
        Const TotalHours = "totHours"
        Const EmpSign = "empSign"
        Const EmpSignDate = "empSignDate"
        Const SupSign = "supSign"
        Const SupSignDate = "supSignDate"
    End Structure

    '' Creates the Time Sheet form:
    Private Function MakeTimeSheetForm() As GcPdfDocument

        Const marginH = 72.0F, marginV = 48.0F
        Dim doc = New GcPdfDocument()
        Dim page = doc.NewPage()
        Dim g = page.Graphics
        Dim ip = New PointF(marginH, marginV)

        Dim tl = New TextLayout() With {.FontCollection = _fc}

        tl.Append("TIME SHEET", New TextFormat() With {.FontName = "Segoe UI", .FontSize = 18})
        tl.PerformLayout(True)
        g.DrawTextLayout(tl, ip)
        ip.Y += tl.ContentHeight + 15

        _logo = Image.FromFile(Path.Combine("Resources", "ImagesBis", "AcmeLogo-vertical-250px.png"))
        Dim s = New SizeF(250.0F * 0.75F, 64.0F * 0.75F)
        g.DrawImage(_logo, New RectangleF(ip, s), Nothing, ImageAlign.Default)
        ip.Y += s.Height + 5

        tl.Clear()
        tl.Append("Where Business meets Technology",
            New TextFormat() With {.FontName = "Segoe UI", .FontItalic = True, .FontSize = 10})
        tl.PerformLayout(True)
        g.DrawTextLayout(tl, ip)
        ip.Y += tl.ContentHeight + 15

        tl.Clear()
        tl.Append($"1901, Halford Avenue,{vbCrLf}Santa Clara, California – 95051-2553,{vbCrLf}United States",
            New TextFormat() With {.FontName = "Segoe UI", .FontSize = 9})
        tl.MaxWidth = page.Size.Width - marginH * 2
        tl.TextAlignment = TextAlignment.Trailing
        tl.PerformLayout(True)
        g.DrawTextLayout(tl, ip)
        ip.Y += tl.ContentHeight + 25

        Dim pen = New Pen(Color.Gray, 0.5F)

        Dim colw = (page.Size.Width - marginH * 2) / 2
        Dim fields1 = DrawTable(ip,
            New Single() {colw, colw},
            New Single() {30, 30, 30},
            g, pen)

        Dim tf = New TextFormat() With {.FontName = "Segoe UI", .FontSize = 9}
        With tl
            .ParagraphAlignment = ParagraphAlignment.Center
            .TextAlignment = TextAlignment.Leading
            .MarginLeft = 4
            .MarginRight = 4
            .MarginTop = 4
            .MarginBottom = 4
        End With

        '' t_ - caption
        '' b_ - bounds
        '' f_ - field name, null means no field
        Dim drawField As Action(Of String, RectangleF, String) =
            Sub(t_, b_, f_)
                Dim tWidth As Single
                If Not String.IsNullOrEmpty(t_) Then
                    tl.Clear()
                    tl.MaxHeight = b_.Height
                    tl.MaxWidth = b_.Width
                    tl.Append(t_, tf)
                    tl.PerformLayout(True)
                    g.DrawTextLayout(tl, b_.Location)
                    tWidth = tl.ContentRectangle.Right
                Else
                    tWidth = 0
                End If
                If Not String.IsNullOrEmpty(f_) Then
                    Dim fld = New TextField() With {.Name = f_}
                    fld.Widget.Page = page
                    fld.Widget.Rect = New RectangleF(
                    b_.X + tWidth + _inputMargin, b_.Y + _inputMargin,
                    b_.Width - tWidth - _inputMargin * 2, b_.Height - _inputMargin * 2)
                    fld.Widget.TextFormat = _inputTf
                    fld.Widget.Border.Color = Color.LightSlateGray
                    fld.Widget.Border.Width = 0.5F
                    doc.AcroForm.Fields.Add(fld)
                End If
            End Sub

        drawField("EMPLOYEE NAME: ", fields1(0, 0), _Names.EmpName)
        drawField("TITLE: ", fields1(1, 0), _Names.EmpTitle)
        drawField("EMPLOYEE NUMBER: ", fields1(0, 1), _Names.EmpNum)
        drawField("STATUS: ", fields1(1, 1), _Names.EmpStatus)
        drawField("DEPARTMENT: ", fields1(0, 2), _Names.EmpDep)
        drawField("SUPERVISOR: ", fields1(1, 2), _Names.EmpSuper)

        ip.Y = fields1(0, 2).Bottom

        Dim col0 = 100.0F
        colw = (page.Size.Width - marginH * 2 - col0) / 5
        Dim rowh = 25.0F
        Dim fields2 = DrawTable(ip,
                New Single() {col0, colw, colw, colw, colw, colw},
                New Single() {50, rowh, rowh, rowh, rowh, rowh, rowh, rowh, rowh},
                g, pen)

        tl.ParagraphAlignment = ParagraphAlignment.Far
        drawField("DATE", fields2(0, 0), Nothing)
        drawField("START TIME", fields2(1, 0), Nothing)
        drawField("END TIME", fields2(2, 0), Nothing)
        drawField("REGULAR HOURS", fields2(3, 0), Nothing)
        drawField("OVERTIME HOURS", fields2(4, 0), Nothing)
        tf.FontBold = True
        drawField("TOTAL HOURS", fields2(5, 0), Nothing)
        tf.FontBold = False
        tl.ParagraphAlignment = ParagraphAlignment.Center
        tf.ForeColor = Color.Gray
        For i = 0 To 6
            drawField(_Names.Dows(i), fields2(0, i + 1), _Names.DtNames(_Names.Dows(i))(0))
        Next

        tf.ForeColor = Color.Black
        For row = 1 To 7
            For col = 1 To 5
                drawField(Nothing, fields2(col, row), _Names.DtNames(_Names.Dows(row - 1))(col))
            Next
        Next

        tf.FontBold = True
        drawField("WEEKLY TOTALS", fields2(0, 8), Nothing)
        tf.FontBold = False

        drawField(Nothing, fields2(3, 8), _Names.TotalReg)
        drawField(Nothing, fields2(4, 8), _Names.TotalOvr)
        drawField(Nothing, fields2(5, 8), _Names.TotalHours)

        ip.Y = fields2(0, 8).Bottom

        col0 = 72 * 4
        colw = page.Size.Width - marginH * 2 - col0
        Dim fields3 = DrawTable(ip,
            New Single() {col0, colw},
            New Single() {rowh + 10, rowh, rowh},
            g, pen)

        drawField("EMPLOYEE SIGNATURE: ", fields3(0, 1), Nothing)
        Dim r = fields3(0, 1)
        _empSignRect = New RectangleF(r.X + r.Width / 2, r.Y, r.Width / 2 - _inputMargin * 2, r.Height)
        Dim sfEmp = New SignatureField() With {.Name = _Names.EmpSign}
        sfEmp.Widget.Rect = New RectangleF(r.X + r.Width / 2, r.Y + _inputMargin, r.Width / 2 - _inputMargin * 2, r.Height - _inputMargin * 2)
        sfEmp.Widget.Page = page
        sfEmp.Widget.BackColor = Color.LightSeaGreen
        doc.AcroForm.Fields.Add(sfEmp)
        drawField("DATE: ", fields3(1, 1), _Names.EmpSignDate)

        drawField("SUPERVISOR SIGNATURE: ", fields3(0, 2), Nothing)
        r = fields3(0, 2)
        Dim sfSup = New SignatureField() With {.Name = _Names.SupSign}
        sfSup.Widget.Rect = New RectangleF(r.X + r.Width / 2, r.Y + _inputMargin, r.Width / 2 - _inputMargin * 2, r.Height - _inputMargin * 2)
        sfSup.Widget.Page = page
        sfSup.Widget.BackColor = Color.LightYellow
        doc.AcroForm.Fields.Add(sfSup)
        drawField("DATE: ", fields3(1, 2), _Names.SupSignDate)

        '' Done:
        Return doc
    End Function

    '' Simple table drawing method. Returns the array of table cell rectangles.
    Private Function DrawTable(ByVal loc As PointF, ByVal widths As Single(), ByVal heights As Single(), ByVal g As GcGraphics, ByVal p As Pen) As RectangleF(,)
        If widths.Length = 0 OrElse heights.Length = 0 Then
            Throw New Exception("Table must have some columns and rows.")
        End If
        Dim cells(widths.Length, heights.Length) As RectangleF
        Dim r = New RectangleF(loc, New SizeF(widths.Sum(), heights.Sum()))
        '' Draw left borders (except for 1st one):
        Dim x = loc.X
        For i = 0 To widths.Length - 1
            For j = 0 To heights.Length - 1
                cells(i, j).X = x
                cells(i, j).Width = widths(i)
            Next
            If (i > 0) Then
                g.DrawLine(x, r.Top, x, r.Bottom, p)
            End If
            x += widths(i)
        Next
        '' Draw top borders (except for 1st one):
        Dim y = loc.Y
        For j = 0 To heights.Length - 1
            For i = 0 To widths.Length - 1
                cells(i, j).Y = y
                cells(i, j).Height = heights(j)
            Next
            If (j > 0) Then
                g.DrawLine(r.Left, y, r.Right, y, p)
            End If
            y += heights(j)
        Next
        '' Draw outer border:
        g.DrawRectangle(r, p)
        '' Done:
        Return cells
    End Function

    '' Fill in employee info and working hours with sample data:
    Private Function FillEmployeeData(ByVal doc As GcPdfDocument) As Stream
        '' For the purposes of this sample, we fill the form with random data:
        Dim empName = "Jaime Smith"
        SetFieldValue(doc, _Names.EmpName, empName)
        SetFieldValue(doc, _Names.EmpNum, "12345")
        SetFieldValue(doc, _Names.EmpDep, "Research & Development")
        SetFieldValue(doc, _Names.EmpTitle, "Senior Developer")
        SetFieldValue(doc, _Names.EmpStatus, "Full Time")
        Dim rand = Util.NewRandom()
        Dim workday = DateTime.Now.AddDays(-15)
        While workday.DayOfWeek <> DayOfWeek.Sunday
            workday = workday.AddDays(1)
        End While
        Dim wkTot = TimeSpan.Zero, wkReg = TimeSpan.Zero, wkOvr = TimeSpan.Zero
        For i = 0 To 6
            '' Start time:
            Dim start = New DateTime(workday.Year, workday.Month, workday.Day, rand.Next(6, 12), rand.Next(0, 59), 0)
            SetFieldValue(doc, _Names.DtNames(_Names.Dows(i))(0), start.ToShortDateString())
            SetFieldValue(doc, _Names.DtNames(_Names.Dows(i))(1), start.ToShortTimeString())
            '' End time:
            Dim endd = start.AddHours(rand.Next(8, 14)).AddMinutes(rand.Next(0, 59))
            SetFieldValue(doc, _Names.DtNames(_Names.Dows(i))(2), endd.ToShortTimeString())
            Dim tot = endd - start
            Dim reg = TimeSpan.FromHours(If(start.DayOfWeek <> DayOfWeek.Saturday AndAlso start.DayOfWeek <> DayOfWeek.Sunday, 8, 0))
            Dim ovr = tot.Subtract(reg)
            SetFieldValue(doc, _Names.DtNames(_Names.Dows(i))(3), reg.ToString("hh\:mm"))
            SetFieldValue(doc, _Names.DtNames(_Names.Dows(i))(4), ovr.ToString("hh\:mm"))
            SetFieldValue(doc, _Names.DtNames(_Names.Dows(i))(5), tot.ToString("hh\:mm"))
            wkTot += tot
            wkOvr += ovr
            wkReg += reg
            ''
            workday = workday.AddDays(1)
        Next
        SetFieldValue(doc, _Names.TotalReg, wkReg.TotalHours.ToString("F"))
        SetFieldValue(doc, _Names.TotalOvr, wkOvr.TotalHours.ToString("F"))
        SetFieldValue(doc, _Names.TotalHours, wkTot.TotalHours.ToString("F"))
        SetFieldValue(doc, _Names.EmpSignDate, workday.ToShortDateString())


        '' Digitally sign the document on behalf of the 'employee':
        Dim pfxPath = Path.Combine("Resources", "Misc", "JohnDoe.pfx")
        Dim cert = New X509Certificate2(File.ReadAllBytes(pfxPath), "secret",
            X509KeyStorageFlags.MachineKeySet Or X509KeyStorageFlags.PersistKeySet Or X509KeyStorageFlags.Exportable)
        Dim sp = New SignatureProperties() With {
            .Certificate = cert,
            .DocumentAccessPermissions = AccessPermissions.FormFillingAndAnnotations,
            .Reason = "I confirm time sheet is correct.",
            .Location = "TimeSheetIncremental sample",
            .SignerName = empName
        }

        '' Connect the signature field and signature props:
        Dim empSign = DirectCast(doc.AcroForm.Fields.First(Function(f_) f_.Name = _Names.EmpSign), SignatureField)
        sp.SignatureField = empSign
        empSign.Widget.ButtonAppearance.Caption = empName
        '' Some browser PDF viewers do not show form fields, so we render a placeholder:
        empSign.Widget.Page.Graphics.DrawString("digitally signed", New TextFormat() With {.FontName = "Segoe UI", .FontSize = 9}, empSign.Widget.Rect)

        '' We now 'flatten' the form: loop over document AcroForm's fields,
        '' drawing their current values in place, and then remove the fields.
        '' This produces a PDF with text fields' values as part of the regular
        '' (non-editable) content (we leave fields filled by the supervisor):
        FlattenDoc(doc, _Names.EmpSuper, _Names.SupSignDate)

        '' Done, now save the document with employee's signature:
        Dim ms = New MemoryStream()
        '' Note that we do NOT use incremental update here (3rd parameter is false)
        '' as this is not needed yet (but will be needed/used when signing by supervisor later)
        doc.Sign(sp, ms, False)
        Return ms
    End Function

    '' Sets the value of a field with the specified name
    Private Sub SetFieldValue(ByVal doc As GcPdfDocument, ByVal name As String, ByVal value As String)
        Dim fld = doc.AcroForm.Fields.First(Function(f_) f_.Name = name)
        If fld IsNot Nothing Then
            fld.Value = value
        End If
    End Sub
End Class