VB.Net PrintForm autofit

Imports System.Drawing
Imports System.Windows.Forms
''' <summary>
''' Prints a screengrab of the form
''' </summary>
''' <remarks></remarks>
Public Class PrintForm
  'USAGE:
  ' Dim pf As New PrintForm(Me)
  ' pf.PrintPreview()
  ' - or-
  ' pf.Print()
'
  Private Declare Auto Function BitBlt Lib "gdi32.dll" (ByVal hDIDest As IntPtr, ByVal nXDest As Integer, ByVal nYDest As Integer, ByVal nWidth As Integer, ByVal nHeight As Integer, ByVal hdcSrc As IntPtr, ByVal nXSrc As Integer, ByVal nYSrc As Integer, ByVal dwRop As System.Int32) As Boolean ' API call to help generate final screenshot
  Private mbmpScreenshot As Bitmap ' Variable to store screenshot
  Private mblnLandscape As Boolean = False
  Public Enum PrintMode_ENUM As Integer
    [Default]
    FitToPage
  End Enum
  Private menuPrintMode As PrintMode_ENUM = PrintMode_ENUM.Default
'
  Private mfrm As Form
  Public Sub New(ByVal frm As Form)
    mfrm = frm
    Call GrabScreen()
  End Sub
'
  ''' <summary>
  ''' Determines page settings for current page e.g. Orientation 
  ''' </summary>
  ''' <param name="sender"></param>
  ''' <param name="e"></param>
  ''' <remarks></remarks>
  Private Sub QueryPageSettings(ByVal sender As System.Object, ByVal e As System.Drawing.Printing.QueryPageSettingsEventArgs)
'
    Dim pgsTemp As System.Drawing.Printing.PageSettings = New System.Drawing.Printing.PageSettings()
    pgsTemp.Landscape = mblnLandscape
    e.PageSettings = pgsTemp
'
  End Sub
'
  Public Sub Print(landscape As Boolean, printMode As PrintMode_ENUM, Optional ByVal docname As String = "PrintForm", Optional ByVal PrinterName As String = "")
    mblnLandscape = landscape
    menuPrintMode = printMode
    'create the document object
    Using pdcNew As New Printing.PrintDocument
'
      'wire up event handlers to handle pagination
      AddHandler pdcNew.PrintPage, AddressOf PrintPage
      AddHandler pdcNew.QueryPageSettings, AddressOf QueryPageSettings
'
      Using docOutput As Printing.PrintDocument = pdcNew
        If PrinterName > "" Then
          docOutput.PrinterSettings.PrinterName = PrinterName
        End If
        docOutput.DocumentName = docname
        docOutput.Print()
      End Using
    End Using
  End Sub
'
  ''' <summary>
  ''' Preview the Report on screen
  ''' </summary>
  ''' <remarks></remarks>
  Public Sub PrintPreview(landscape As Boolean, printMode As PrintMode_ENUM, Optional ByVal docname As String = "PrintForm", Optional ByVal Owner As Form = Nothing)
    mblnLandscape = landscape
    menuPrintMode = printMode
'
    'create the document object
    Using pdcNew As New Printing.PrintDocument
'
      'wire up event handlers to handle pagination
      AddHandler pdcNew.PrintPage, AddressOf PrintPage
      AddHandler pdcNew.QueryPageSettings, AddressOf QueryPageSettings
'
      Using ppvPreview As New PrintPreviewDialog
        ppvPreview.Document = pdcNew
        ppvPreview.FindForm.WindowState = FormWindowState.Maximized
        If IsNothing(Owner) Then
          ppvPreview.ShowDialog()
        Else
          ppvPreview.ShowDialog(Owner)
        End If
      End Using
    End Using
  End Sub
  Sub PrintPage(ByVal sender As System.Object, ByVal e As System.Drawing.Printing.PrintPageEventArgs)
    Dim g As Graphics = e.Graphics 'shortcut
    'g.DrawRectangle(Pens.Red, e.MarginBounds) 'DEBUG: use this line to check margins        
'
    ' Method that handles the printing
    Using objImageToPrint As Graphics = e.Graphics
      Select Case menuPrintMode
        Case PrintMode_ENUM.FitToPage
          Dim rctTarget As Rectangle
          If (mbmpScreenshot.Width / mbmpScreenshot.Height) < (e.MarginBounds.Width / e.MarginBounds.Height) Then
            'fit height
            rctTarget = New Rectangle(e.MarginBounds.X, e.MarginBounds.Y, CInt(mbmpScreenshot.Width * e.MarginBounds.Height / mbmpScreenshot.Height), e.MarginBounds.Height)
          Else
            'fit width
            rctTarget = New Rectangle(e.MarginBounds.X, e.MarginBounds.Y, e.MarginBounds.Width, CInt(mbmpScreenshot.Height * e.MarginBounds.Width / mbmpScreenshot.Width))
          End If
          'g.DrawRectangle(Pens.Blue, rctTarget) 'DEBUG: use this line to check target rectangle
          objImageToPrint.DrawImage(mbmpScreenshot, rctTarget)
        Case Else 'default
          objImageToPrint.DrawImage(mbmpScreenshot, 0, 0)
      End Select
    End Using
'
    e.HasMorePages = False
  End Sub
'
  Private Sub GrabScreen()
    ' Performs a screenshot, saving results to bmpScreenshot
    Dim objGraphics As Graphics = mfrm.CreateGraphics
    Dim rctForm As Rectangle = mfrm.ClientRectangle 'including the border is beyond the scope of this demo program. See http://support.microsoft.com/kb/84066 for GetSystemMetrics() API to get  size of border
'
    Const SRCCOPY As Integer = &HCC0020
    mbmpScreenshot = New Bitmap(rctForm.Width, rctForm.Height, objGraphics)
    Dim objGraphics2 As Graphics = Graphics.FromImage(mbmpScreenshot)
    Dim deviceContext1 As IntPtr = objGraphics.GetHdc
    Dim deviceContext2 As IntPtr = objGraphics2.GetHdc
'
    BitBlt(deviceContext2, rctForm.X, rctForm.Y, rctForm.Width, rctForm.Height, deviceContext1, 0, 0, SRCCOPY)
    objGraphics.ReleaseHdc(deviceContext1)
    objGraphics2.ReleaseHdc(deviceContext2)
  End Sub
'
End Class
'