''' <summary>
''' Packs the PDF document.
''' </summary>
''' <param name="inPdfFilename">The input PDF filename.</param>
''' <param name="outPdfFilename">The output PDF filename.</param>
Public Shared Sub PackDocument(inPdfFilename As String, outPdfFilename As String)
    ' create compressor with empty compression settings
    Dim compressor As Vintasoft.Imaging.Pdf.Processing.PdfDocumentCompressorCommand = Vintasoft.Imaging.Pdf.Processing.PdfDocumentCompressorCommand.CreateEmptyCompressor()

    ' specify that compressor must use maximum Flate compression level (best compression)
    compressor.FlateCompressionLevel = 9
    ' specify that compressor must recompress all resource that uses None, LZW, Flate compression using Flate compression
    compressor.RecompressFlateCompression = True
    compressor.UseFlateInsteadLzwCompression = True
    compressor.UseFlateInsteadNoneCompression = True

    ' specify that compressor must remove incremental update info and unused objects
    compressor.PackDocument = True

    ' if version of PDF document is lower than 1.7
    If GetPdfDocumentVersion(inPdfFilename) < 17 Then
        ' set output format to PDF 1.7
        compressor.DocumentPackFormat = Vintasoft.Imaging.Pdf.PdfFormat.Pdf_17
    End If

    ' compress PDF document
    compressor.Compress(inPdfFilename, outPdfFilename)
End Sub

''' <summary>
''' Returns the PDF document version.
''' </summary>
''' <param name="pdfFilename">The PDF filename.</param>
''' <returns>The version number in dual-digit format (10,11,12,13,14,15,16,17,20,...).</returns>
Private Shared Function GetPdfDocumentVersion(pdfFilename As String) As Integer
    Using document As New Vintasoft.Imaging.Pdf.PdfDocument(pdfFilename)
        Return document.Format.VersionNumber
    End Using
End Function

/// <summary>
/// Packs the PDF document.
/// </summary>
/// <param name="inPdfFilename">The input PDF filename.</param>
/// <param name="outPdfFilename">The output PDF filename.</param>
public static void PackDocument(string inPdfFilename, string outPdfFilename)
{
    // create compressor with empty compression settings
    Vintasoft.Imaging.Pdf.Processing.PdfDocumentCompressorCommand compressor =
        Vintasoft.Imaging.Pdf.Processing.PdfDocumentCompressorCommand.CreateEmptyCompressor();

    // specify that compressor must use maximum Flate compression level (best compression)
    compressor.FlateCompressionLevel = 9;
    // specify that compressor must recompress all resource that uses None, LZW, Flate compression using Flate compression
    compressor.RecompressFlateCompression = true;
    compressor.UseFlateInsteadLzwCompression = true;
    compressor.UseFlateInsteadNoneCompression = true;

    // specify that compressor must remove incremental update info and unused objects
    compressor.PackDocument = true;

    // if version of PDF document is lower than 1.7
    if (GetPdfDocumentVersion(inPdfFilename) < 17)
    {
        // set output format to PDF 1.7
        compressor.DocumentPackFormat = Vintasoft.Imaging.Pdf.PdfFormat.Pdf_17;
    }

    // compress PDF document
    compressor.Compress(inPdfFilename, outPdfFilename);
}

/// <summary>
/// Returns the PDF document version.
/// </summary>
/// <param name="pdfFilename">The PDF filename.</param>
/// <returns>The version number in dual-digit format (10,11,12,13,14,15,16,17,20,...).</returns>
private static int GetPdfDocumentVersion(string pdfFilename)
{
    using (Vintasoft.Imaging.Pdf.PdfDocument document = new Vintasoft.Imaging.Pdf.PdfDocument(pdfFilename))
        return document.Format.VersionNumber;
}