Victor Image Processing Library How-to Tips

Printing with Visual Basic

In this first example we'll print an image 3 inches wide at the top of the page. The image has previously been loaded and is defined by vimage, a global variable that holds the image descriptor.

The second example prints text and an image and also makes use of a callback function to allow the user to cancel the print job. The implementation of a callback function uses the VB AddressOf operator available in VB v 5 or later.

Example 1. Print an Image - the Source Code for VB

........... Add these declarations to your Global module ...........

Declare Function printimage Lib "VIC32.DLL" (ByVal hWnd As Long, ByVal hdcprn As Long, ByVal mode As Long, image As imgdes, pRect As RECT, ByVal boxsiz As Long, ByVal dspfct As Long) As Long
Declare Sub RtlMoveMemory Lib "kernel32" (ByVal des As Long, ByVal src As Long, ByVal cnt As Long)
Declare Sub CopyMemory Lib "kernel32" Alias "RtlMoveMemory" (des As Any, ByVal src As Long, ByVal cnt As Long)

............ Add this function to your .BAS module, not to a .FRM module ...........

Public Function print_an_image(hWnd As Long) As Long
Dim rcode As Long
Dim pRect As RECT
Dim boxsize As Long, mode As Long
Dim bm As BITMAPINFOHEADER
   
    boxsize = 0     ' Size of frame around printed image
    mode = 0        ' Use default print mode
    ' Get Bitmap info
    CopyMemory bm, vimage.bmh, 40   ' 40=size of BITMAPINFOHEADER
    
    pRect.top = 0   ' Position of printed area on printed page in 1/1000 inch units
    pRect.left = 1000                ' One inch from left
    pRect.right = pRect.left + 3000  ' Print image 3 inches wide
    ' Maintain aspect ratio of image
    pRect.bottom = (pRect.right - pRect.left) * bm.biHeight / bm.biWidth

    ' Print the image
    rcode = printimage(hWnd, Printer.hdc, mode, vimage, pRect, boxsize, 0)

print_an_image = rcode

End Function

Example 2. Print Text and an Image, Implement a Callback Function
- the Source Code for VB

........... Add these declarations to your Global module ...........
Declare Function printimagenoeject Lib "VIC32.DLL" (ByVal hWnd As Long, ByVal hdcprn As Long, ByVal mode As Long, image As imgdes, pRect As RECT, ByVal boxsiz As Long, ByVal dspfct As Long) As Long
Declare Sub RtlMoveMemory Lib "kernel32" (ByVal des As Long, ByVal src As Long, ByVal cnt As Long)
Declare Sub CopyMemory Lib "kernel32" Alias "RtlMoveMemory" (des As Any, ByVal src As Long, ByVal cnt As Long)
Global cancelprt As Long   ' Print-cancel flag, set to 1 when cancel button is clicked

............ Add these functions to your .BAS module, not to a .FRM module ...........

Public Function displayprintcancelbox(ByVal progress As Long) As Long
   ' printimage() callback function

   If printprogress.Visible = True Then  ' If dialog is visible, display band number
      printprogress.Label1 = LCase$("printing band number  " & progress)
   End If

' Print-cancel flag is set to 1 when cancel button is clicked
' If return value is 1, printimage will cancel printing
displayprintcancelbox = cancelprt

End Function

Public Function dotheprintwithcancelbox(hWnd As Long) As Long
Dim rcode As Long
Dim pRect As RECT
Dim docname As String
Dim boxsize As Long, mode As Long
Dim dspfct As Long
Dim bm As BITMAPINFOHEADER
   
    boxsize = 0     ' Size of frame around printed image
    mode = 0        ' Use default print mode
    docname = "Victor Library"  'Print Manager job name
    ' Get Bitmap info
    CopyMemory bm, vimage.bmh, 40   ' 40=size of BITMAPINFOHEADER
    
    pRect.top = 0   ' Position of printed area on printed page in 1/1000 inch units
    pRect.left = 1000                ' One inch from left
    pRect.right = pRect.left + 3000  ' Print image 3 inches wide
    ' Maintain aspect ratio of image
    pRect.bottom = (pRect.right - pRect.left) * bm.biHeight / bm.biWidth

    ' Print some text below the picture
    Printer.ScaleMode = 5 ' Inches
    Printer.CurrentX = 1  ' One inch from left
    Printer.CurrentY = (pRect.bottom + 1000 / 4) / 1000 ' 1/4 inch below picture
    Printer.Print "This is a Victor Image"
    
    Screen.MousePointer = 11  ' Display the hourglass mouse pointer.

    cancelprt = 0  ' Clear cancel printing flag
    printprogress.Show  ' Display print progress dialog
    
    ' Print the image
    rcode = printimagenoeject(hWnd, Printer.hdc, mode, vimage, pRect, boxsize, AddressOf displayprintcancelbox)
    
    printprogress.Hide  ' Hide print progress dialog
        
    Screen.MousePointer = 0  ' Restore mouse pointer

    If rcode <> NO_ERROR Then
        Printer.KillDoc ' Cancel printing if error
    End If
    Printer.EndDoc
    
    ' Handle any errors
    If rcode <> NO_ERROR Then
        MainWnd.error_handler rcode, ""
    End If

dotheprintwithcancelbox = rcode

End Function

............ Add to the printprogress.frm module ...........

Private Sub Command1_Click()
    ' When the user clicks "Cancel" button in the print progress dialog box
    cancelprt = 1
End Sub

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