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Q146022: HOWTO: Set Up the RichTextBox Control for WYSIWYG Printing

Article: Q146022
Product(s): Microsoft Visual Basic for Windows
Version(s): 4.0,5.0,6.0
Operating System(s): 
Keyword(s): kbprint kbtophit kbPrinting KbVBA kbVBp kbVBp400 kbVBp500 kbVBp600 kbGrpDSVB
Last Modified: 05-FEB-2002

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The information in this article applies to:

- Microsoft Visual Basic Learning Edition for Windows, versions 5.0, 6.0 
- Microsoft Visual Basic Professional Edition for Windows, versions 5.0, 6.0 
- Microsoft Visual Basic Enterprise Edition for Windows, versions 5.0, 6.0 
- Microsoft Visual Basic Professional Edition, 32-bit, for Windows, version 4.0 
- Microsoft Visual Basic Enterprise Edition, 32-bit, for Windows, version 4.0 
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SUMMARY
=======

The SelPrint method of the RichTextBox control does not allow a programmer to
set the position of the output on the printer. In addition, the RichTextBox
control does not provide a method for displaying its contents as they would show
up on the printer. This article explains how to set up a RichTextBox with a
WYSIWYG (What You See Is What You Get) display and then how to print it.

MORE INFORMATION
================

The Visual Basic RichTextBox control is a sub-classed control based on the
RichTextBox provided by the Win32 operating system. The operating system control
supports many messages that are not exposed in Visual Basic. One of these
messages is EM_SETTARGETDEVICE. The EM_SETTARGETDEVICE message is used to tell a
RichTextBox to base its display on a target device such as a printer. Another
message that is not fully exposed by Visual Basic is EM_FORMATRANGE. The
EM_FORMATRANGE message sends a page at a time to an output device using the
specified coordinates. Using these messages in Visual Basic, it is possible to
make a RichTextBox support WYSIWYG display and output.

The following example illustrates how to take advantage of the EM_SETTARGETDEVICE
and EM_FORMATRANGE messages from Visual Basic. The example provides two
re-usable procedures to send these messages. The first procedure WYSIWYG_RTF()
sets a RichTextBox to provide a WYSIWYG display based on the default printer and
specified margins. The second procedure PrintRtf() prints the contents of the
RichTextBox with the specified margins.

EXAMPLE
-------

1. Start a new project in the Visual Basic 32-bit edition. Form1 is created by
  default.

2. Put a CommandButton and a RichTextBox control on Form1.

3. Add the following code to Form1:

  Private Const AnInch As Long = 1440   '1440 twips per inch
  Private Const QuarterInch As Long = 360

  Private Sub Form_Load()
     Dim PrintableWidth As Long
     Dim PrintableHeight As Long
     Dim x As Single

     ' Initialize Form and Command button
     Me.Caption = "Rich Text Box WYSIWYG Printing Example"
     Command1.Move 10, 10, 600, 380
     Command1.Caption = "&Print"

     ' Set the font of the RTF to a TrueType font for best results
     RichTextBox1.SelFontName = "Arial"
     RichTextBox1.SelFontSize = 10
     
     'initialize the printer object
     x = Printer.TwipsPerPixelX
     Printer.Orientation = vbPRORPortrait  'vbPRORLandscape

     ' Tell the RTF to base it's display off of the printer
     Call WYSIWYG_RTF(RichTextBox1, QuarterInch, QuarterInch, QuarterInch, QuarterInch, PrintableWidth, PrintableHeight) '1440 Twips=1 Inch

     ' Set the form width to match the line width
     Me.Width = PrintableWidth + 200
     Me.Height = PrintableHeight + 800
  End Sub

  Private Sub Form_Resize()
     ' Position the RTF on form
     RichTextBox1.Move 100, 500, Me.ScaleWidth - 200, Me.ScaleHeight - 600
  End Sub

  Private Sub Command1_Click()
     ' Print the contents of the RichTextBox with a one inch margin
     PrintRTF RichTextBox1, AnInch, AnInch, AnInch, AnInch
  End Sub

4. Insert a new standard module into the project, Module1.bas is created by
  default.

5. Add the following code to Module1:

  Option Explicit

  Private Type Rect
     Left As Long
     Top As Long
     Right As Long
     Bottom As Long
  End Type

  Private Type CharRange
    cpMin As Long     ' First character of range (0 for start of doc)
    cpMax As Long     ' Last character of range (-1 for end of doc)
  End Type

  Private Type FormatRange
    hdc As Long       ' Actual DC to draw on
    hdcTarget As Long ' Target DC for determining text formatting
    rc As Rect        ' Region of the DC to draw to (in twips)
    rcPage As Rect    ' Region of the entire DC (page size) (in twips)
    chrg As CharRange ' Range of text to draw (see above declaration)
  End Type

  Private Const WM_USER As Long = &H400
  Private Const EM_FORMATRANGE As Long = WM_USER + 57
  Private Const EM_SETTARGETDEVICE As Long = WM_USER + 72
  Private Const PHYSICALOFFSETX As Long = 112
  Private Const PHYSICALOFFSETY As Long = 113

  Private Declare Function GetDeviceCaps Lib "gdi32" ( _
     ByVal hdc As Long, ByVal nIndex As Long) As Long
  Private Declare Function SendMessage Lib "USER32" Alias "SendMessageA" _
     (ByVal hWnd As Long, ByVal msg As Long, ByVal wp As Long, _
     lp As Any) As Long
  Private Declare Function CreateDC Lib "gdi32" Alias "CreateDCA" _
     (ByVal lpDriverName As String, ByVal lpDeviceName As String, _
     ByVal lpOutput As Long, ByVal lpInitData As Long) As Long

  ''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
  '
  ' WYSIWYG_RTF - Sets an RTF control to display itself the same as it
  '               would print on the default printer
  '
  ' RTF - A RichTextBox control to set for WYSIWYG display.
  '
  ' LeftMarginWidth - Width of desired left margin in twips
  '
  ' RightMarginWidth - Width of desired right margin in twips
  '
  ' Returns - The length of a line on the printer in twips
  '''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
  Public Sub WYSIWYG_RTF(RTF As RichTextBox, LeftMarginWidth As Long, RightMarginWidth As Long, TopMarginWidth As Long, BottomMarginWidth As Long, PrintableWidth As Long, PrintableHeight As Long)
     Dim LeftOffset As Long
     Dim LeftMargin As Long
     Dim RightMargin As Long
     Dim TopOffset As Long
     Dim TopMargin As Long
     Dim BottomMargin As Long
     Dim PrinterhDC As Long
     Dim r As Long

     ' Start a print job to initialize printer object
     Printer.Print Space(1)
     Printer.ScaleMode = vbTwips
     
     ' Get the left offset to the printable area on the page in twips
     LeftOffset = GetDeviceCaps(Printer.hdc, PHYSICALOFFSETX)
     LeftOffset = Printer.ScaleX(LeftOffset, vbPixels, vbTwips)
     
     ' Calculate the Left, and Right margins
     LeftMargin = LeftMarginWidth - LeftOffset
     RightMargin = (Printer.Width - RightMarginWidth) - LeftOffset
     
     ' Calculate the line width
     PrintableWidth = RightMargin - LeftMargin
     
     ' Get the top offset to the printable area on the page in twips
     TopOffset = GetDeviceCaps(Printer.hdc, PHYSICALOFFSETY)
     TopOffset = Printer.ScaleX(TopOffset, vbPixels, vbTwips)
     
     ' Calculate the Left, and Right margins
     TopMargin = TopMarginWidth - TopOffset
     BottomMargin = (Printer.Height - BottomMarginWidth) - TopOffset
     
     ' Calculate the line width
     PrintableHeight = BottomMargin - TopMargin
      
     
     ' Create an hDC on the Printer pointed to by the Printer object
     ' This DC needs to remain for the RTF to keep up the WYSIWYG display
     PrinterhDC = CreateDC(Printer.DriverName, Printer.DeviceName, 0, 0)

     ' Tell the RTF to base it's display off of the printer
     '    at the desired line width
     r = SendMessage(RTF.hWnd, EM_SETTARGETDEVICE, PrinterhDC, _
        ByVal PrintableWidth)

     ' Abort the temporary print job used to get printer info
     Printer.KillDoc
  End Sub

  ''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
  '
  ' PrintRTF - Prints the contents of a RichTextBox control using the
  '            provided margins
  '
  ' RTF - A RichTextBox control to print
  '
  ' LeftMarginWidth - Width of desired left margin in twips
  '
  ' TopMarginHeight - Height of desired top margin in twips
  '
  ' RightMarginWidth - Width of desired right margin in twips
  '
  ' BottomMarginHeight - Height of desired bottom margin in twips
  '
  ' Notes - If you are also using WYSIWYG_RTF() on the provided RTF
  '         parameter you should specify the same LeftMarginWidth and
  '         RightMarginWidth that you used to call WYSIWYG_RTF()
  ''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
  Public Sub PrintRTF(RTF As RichTextBox, LeftMarginWidth As Long, _
     TopMarginHeight, RightMarginWidth, BottomMarginHeight)
     Dim LeftOffset As Long, TopOffset As Long
     Dim LeftMargin As Long, TopMargin As Long
     Dim RightMargin As Long, BottomMargin As Long
     Dim fr As FormatRange
     Dim rcDrawTo As Rect
     Dim rcPage As Rect
     Dim TextLength As Long
     Dim NextCharPosition As Long
     Dim r As Long

     ' Start a print job to get a valid Printer.hDC
     Printer.Print Space(1)
     Printer.ScaleMode = vbTwips

     ' Get the offsett to the printable area on the page in twips
     LeftOffset = Printer.ScaleX(GetDeviceCaps(Printer.hdc, _
        PHYSICALOFFSETX), vbPixels, vbTwips)
     TopOffset = Printer.ScaleY(GetDeviceCaps(Printer.hdc, _
        PHYSICALOFFSETY), vbPixels, vbTwips)

     ' Calculate the Left, Top, Right, and Bottom margins
     LeftMargin = LeftMarginWidth - LeftOffset
     TopMargin = TopMarginHeight - TopOffset
     RightMargin = (Printer.Width - RightMarginWidth) - LeftOffset
     BottomMargin = (Printer.Height - BottomMarginHeight) - TopOffset

     ' Set printable area rect
     rcPage.Left = 0
     rcPage.Top = 0
     rcPage.Right = Printer.ScaleWidth
     rcPage.Bottom = Printer.ScaleHeight

     ' Set rect in which to print (relative to printable area)
     rcDrawTo.Left = LeftMargin
     rcDrawTo.Top = TopMargin
     rcDrawTo.Right = RightMargin
     rcDrawTo.Bottom = BottomMargin

     ' Set up the print instructions
     fr.hdc = Printer.hdc   ' Use the same DC for measuring and rendering
     fr.hdcTarget = Printer.hdc  ' Point at printer hDC
     fr.rc = rcDrawTo            ' Indicate the area on page to draw to
     fr.rcPage = rcPage          ' Indicate entire size of page
     fr.chrg.cpMin = 0           ' Indicate start of text through
     fr.chrg.cpMax = -1          ' end of the text

     ' Get length of text in RTF
     TextLength = Len(RTF.Text)

     ' Loop printing each page until done
     Do
        ' Print the page by sending EM_FORMATRANGE message
        NextCharPosition = SendMessage(RTF.hWnd, EM_FORMATRANGE, True, fr)
        If NextCharPosition >= TextLength Then Exit Do  'If done then exit
        fr.chrg.cpMin = NextCharPosition ' Starting position for next page
        Printer.NewPage                  ' Move on to next page
        Printer.Print Space(1) ' Re-initialize hDC
        fr.hdc = Printer.hdc
        fr.hdcTarget = Printer.hdc
     Loop

     ' Commit the print job
     Printer.EndDoc

     ' Allow the RTF to free up memory
     r = SendMessage(RTF.hWnd, EM_FORMATRANGE, False, ByVal CLng(0))
  End Sub

6. Save the project.

7. Run the project.

8. Enter or paste some text into the RichTextBox.

9. Press the Print command button. Note that the printed output should word-wrap
  at the same locations as displayed on the screen. Also, the output should be
  printed with the specified one-inch margin all around.

Additional query words:

======================================================================
Keywords          : kbprint kbtophit kbPrinting KbVBA kbVBp kbVBp400 kbVBp500 kbVBp600 kbGrpDSVB 
Technology        : kbVBSearch kbAudDeveloper kbZNotKeyword6 kbZNotKeyword2 kbVB500Search kbVB600Search kbVB500 kbVB600 kbVB400Search kbVB400
Version           : :4.0,5.0,6.0
Issue type        : kbhowto

=============================================================================

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