VB Converter - SDK sample

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Feb 25, 2019

novaPDF SDK

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VB Converter - SDK sample

The VB Converter sample demonstrates how to convert an existing file by printing it to novaPDF Printer using the ShellExecute function. It also demonstrates how to set different options and manage profiles in the novaPDF SDK application.

Note
To be able to use the samples you must install novaPDF SDK as samples work only with it. Download it here: novaPDF SDK.

The same approach should be used if you print using a Print() method from another object (like an internet browser or a report control). Just replace the ShellExecute call with the call of your Print method.

When the application starts, it creates a few profiles and makes different settings in the profiles. Then it shows a dialog from where the user can select the active profile and change its settings using the controls from the dialog. After that a document can be selected from the harddisk and printed to novaPDF Printer using the ShellExecute function call.

When using this technique to convert a file to PDF, you have to take care of the fact that ShellExecute prints to the default printer. This function returns immediately and does not wait until the print is finished (it may return before the printing is actually started).

Therefore you have to set the default printer to novaPDF Printer before calling ShellExecute (using the SetDefaultPrinter method), register FileSaved message (or any other novaPDF Printer message) to be sure that the print job was started.

In this message handler restore the default printer (with the RestoreDefaultPrinter method). This way you made sure that the default printer was restored and your document is printed to novaPDF Printer.

Source Code Snippets

1. Declare INovaPdfOptions variable
'create the NovaPdfOptions object
Public m_NovaOptions As New NovaPdfOptions80

2. Register <%SDK_SAMPLE_PRINTER%> messages
Public wm_Nova_FileSaved As Long
Public wm_Nova_PrintError As Long

Sub Main()
    ' Registering the messages send by the print in order to listen for them
    wm_Nova_FileSaved = RegisterWindowMessage(MSG_NOVAPDF2_FILESAVED)
    wm_Nova_PrintError = RegisterWindowMessage(MSG_NOVAPDF2_PRINTERROR)
    Form1.Show
End Sub

' Sub that will handle the windows messages
Public Function VB_WindowProc(ByVal hwnd As Long, ByVal wMsg As Long, ByVal wParam As Long, ByVal lParam As Long) As Long
    ' For the registered messages perform specific tasks
    If wMsg = wm_Nova_FileSaved Then
        OnNovaPDFFileSaved wParam, lParam
        Exit Function
    End If
    If wMsg = wm_Nova_PrintError Then
        OnNovaPDFPrintError wParam, lParam
        Exit Function
    End If

    ' For other messages just send them via normal (old) handling process
    VB_WindowProc = CallWindowProc(oldHandler, hwnd, wMsg, wParam, lParam)
End Function

3. Initialize INovaPdfOptions
Private Sub Form_Load()

    On Error GoTo ErrorHandler:
    Dim strProfileID As String
    Dim strProfileName As String
    Dim strActiveProfileID As String
    Dim nPublicProfile As Long
    Dim nActivePublicProfile As Long

    ' initialize the NovaPdfOptions object to use with a printer licensed for SDK
    m_NovaOptions.Initialize (PRINTER_NAME, "")

    ' sets the value of the windows messages handler to VB_WindowProc and sets the old handler address of function in oldHandler
    oldHandler = SetWindowLongApi(Me.hwnd, GWL_WNDPROC, AddressOf VB_WindowProc)

    cmbProfiles.Clear

    Call AddSmallSize
    Call AddFullOptions

    ' get the active profile ...
    m_NovaOptions.GetActiveProfile2 strActiveProfileID

    m_NovaOptions.GetFirstProfile2 strProfileID
    m_NovaOptions.LoadProfile2 strProfileID
    m_NovaOptions.GetOptionString2 NOVAPDF_PROFILE_NAME, strProfileName
    cmbProfiles.AddItem (strProfileName)

    On Error Resume Next
    Do
        m_NovaOptions.GetNextProfile2 (strProfileID)
        If err.Number = NV_NO_MORE_PROFILES Then
            Exit Do
        End If
        m_NovaOptions.LoadProfile2 strProfileID
        m_NovaOptions.GetOptionString2 NOVAPDF_PROFILE_NAME, strProfileName
        cmbProfiles.AddItem (strProfileName)
    Loop While True

    On Error GoTo ErrorHandler:

    cmbProfiles.ListIndex = 0

    UpdateDialogFromProfile
    Exit Sub
ErrorHandler:
    Debug.Print err.Number & ":" & err.Description
End Sub

4. Set <%SDK_SAMPLE_PRINTER%> Options
Private Sub AddSmallSize()
    Dim strProfileID As String
    On Error GoTo ErrHandler

    m_NovaOptions.AddProfile2 SMALL_SIZE_PROFILE, PROFILE_IS_PUBLIC, strProfileID
    m_NovaOptions.LoadProfile2 (strProfileID)

    ' Set some options to this profile

    ' disable the "Save PDF file as" prompt
    m_NovaOptions.SetOptionLong2 NOVAPDF_SAVE_PROMPT_TYPE, PROMPT_SAVE_NONE
    ' set generated Pdf files destination folder  "c:\"
    m_NovaOptions.SetOptionString2 NOVAPDF_SAVE_FOLDER, "c:\"
    ' set output file name
    m_NovaOptions.SetOptionString2 NOVAPDF_SAVE_FILE_NAME, "PDF Converter small size.pdf"
    ' if file exists in the destination folder, append a counter to the end of the file name
    m_NovaOptions.SetOptionLong2 NOVAPDF_SAVE_FILEEXIST_ACTION, FILE_CONFLICT_STRATEGY_AUTONUMBER_NEW
    ' don't detect URLs
    m_NovaOptions.SetOptionLong2 NOVAPDF_URL_ANALIZE, False

    ' Set image compresion method to JPEG and quality to 75, possible values are from 10 to 100
    m_NovaOptions.SetOptionLong2 NOVAPDF_COMPRESS_ENABLE, True
    m_NovaOptions.SetOptionLong2 NOVAPDF_COMPRESS_HIGH_COLOR, True
    m_NovaOptions.SetOptionLong2 NOVAPDF_COMPRESS_HIGH_COLOR_TYPE, COMPRESS_METHOD_JPEG
    m_NovaOptions.SetOptionLong2 NOVAPDF_COMPRESS_HIGH_COLOR_LEVEL, 75

    ' make sure text compression is enabled, and set compression level to 9  maximum   posible values are 1-9
    m_NovaOptions.SetOptionLong2 NOVAPDF_COMPRESS_TEXT_GRAPHICS, True
    m_NovaOptions.SetOptionLong2 NOVAPDF_COMPRESS_TEXT_GRAPHICS_LEVEL, 9

    ' disable unused font embeding
    m_NovaOptions.SetOptionLong2 NOVAPDF_FONTS_EMBED_ALL_USED_FONTS, False

    'save profile changes
    m_NovaOptions.SaveProfile

    Exit Sub
ErrHandler:
    If err.Number <> NV_PROFILE_EXISTS Then Debug.Print err.Number & ":" & err.Description

End Sub

5. Start a Print job
Private Sub btnStartPrinting_Click()
......
    m_NovaOptions.SetActiveProfile2 (strProfileID)
    m_NovaOptions.SetDefaultPrinter
    Dim strToExecute As String
    Dim r As Long
    m_NovaOptions.RegisterEventWindow Me.hwnd
    m_NovaOptions.LicenseShellExecuteFile txtFileToConvert
    r = ShellExecute(Me.hwnd, "print", txtFileToConvert, "", "", SW_HIDE)
    btnStartPrinting.Enabled = True
.....
End Sub

6. Restore default printer when printing finished
Private Sub OnNovaPDFFileSaved(wParam As Long, lParam As Long)
    m_NovaOptions.UnRegisterEventWindow
    m_NovaOptions.RestoreDefaultPrinter
End Sub

Private Sub OnNovaPDFPrintError(wParam As Long, lParam As Long)
    Select Case wParam
        Case ERROR_MSG_TEMP_FILE:
            MsgBox "Error saving temporary file on printer server", vbOKOnly, "novaPDF"
        Case ERROR_MSG_LIC_INFO:
            MsgBox "Error reading license information", vbOKOnly, "novaPDF"
        Case ERROR_MSG_SAVE_PDF:
            MsgBox "Error saving PDF file", vbOKOnly, "novaPDF"
        Case ERROR_MSG_JOB_CANCELED:
            MsgBox "Print job was canceled", vbOKOnly, "novaPDF"
    End Select
    m_NovaOptions.UnRegisterEventWindow
    m_NovaOptions.RestoreDefaultPrinter
End Sub