/// <summary>
/// Creates a single page PDF document using only PDF basic types (basic PDF tree).
/// </summary>
/// <param name="outputPdfFilename">The output PDF filename.</param>
public static void CreatePdfDocumentUseBasicTypes(string outputPdfFilename)
{
    using (Vintasoft.Imaging.Pdf.PdfDocument document = 
        new Vintasoft.Imaging.Pdf.PdfDocument(Vintasoft.Imaging.Pdf.PdfFormat.Pdf_14))
    {
        Vintasoft.Imaging.Pdf.BasicTypes.PdfDictionary catalog = 
            GetBasicObject<Vintasoft.Imaging.Pdf.BasicTypes.PdfDictionary>(document.Catalog.BasicObject);

        Vintasoft.Imaging.Pdf.BasicTypes.PdfDictionary pages = 
            GetBasicObject<Vintasoft.Imaging.Pdf.BasicTypes.PdfDictionary>(catalog["Pages"]);

        pages["Count"] = new Vintasoft.Imaging.Pdf.BasicTypes.PdfIntegerNumber(1);
        Vintasoft.Imaging.Pdf.BasicTypes.PdfDictionary page = 
            new Vintasoft.Imaging.Pdf.BasicTypes.PdfDictionary(document);
        pages["Kids"] = new Vintasoft.Imaging.Pdf.BasicTypes.PdfArray(document, 
            Vintasoft.Imaging.Pdf.BasicTypes.PdfIndirectObject.Create(document, page).GetReference());

        page["Type"] = new Vintasoft.Imaging.Pdf.BasicTypes.PdfName("Page");
        page["Parent"] = catalog["Pages"];
        page["MediaBox"] = new Vintasoft.Imaging.Pdf.BasicTypes.PdfArray(document,
            Vintasoft.Imaging.Pdf.BasicTypes.PdfNumber.Create(0),
            Vintasoft.Imaging.Pdf.BasicTypes.PdfNumber.Create(0),
            Vintasoft.Imaging.Pdf.BasicTypes.PdfNumber.Create(300),
            Vintasoft.Imaging.Pdf.BasicTypes.PdfNumber.Create(400));

        Vintasoft.Imaging.Pdf.BasicTypes.PdfDictionary font = 
            new Vintasoft.Imaging.Pdf.BasicTypes.PdfDictionary(document);
        font["Type"] = new Vintasoft.Imaging.Pdf.BasicTypes.PdfName("Font");
        font["Subtype"] = new Vintasoft.Imaging.Pdf.BasicTypes.PdfName("Type1");
        font["BaseFont"] = new Vintasoft.Imaging.Pdf.BasicTypes.PdfName("Times-Roman");
        font["Encoding"] = new Vintasoft.Imaging.Pdf.BasicTypes.PdfName("WinAnsiEncoding");

        Vintasoft.Imaging.Pdf.BasicTypes.PdfDictionary fontResources = 
            new Vintasoft.Imaging.Pdf.BasicTypes.PdfDictionary(document);
        fontResources["F1"] = Vintasoft.Imaging.Pdf.BasicTypes.PdfIndirectObject.Create(document, font).GetReference();
        Vintasoft.Imaging.Pdf.BasicTypes.PdfDictionary pageResources = 
            new Vintasoft.Imaging.Pdf.BasicTypes.PdfDictionary(document);
        pageResources["Font"] = fontResources;
        page["Resources"] = pageResources;

        string content = "q /F1 20 Tf BT 100 200 Td (Hello World!) Tj ET Q";
        Vintasoft.Imaging.Pdf.BasicTypes.PdfStream contentStream = 
            new Vintasoft.Imaging.Pdf.BasicTypes.PdfStream(document);
        contentStream.SetBytes(
            System.Text.Encoding.ASCII.GetBytes(content), 
            Vintasoft.Imaging.Pdf.PdfCompression.None,
            Vintasoft.Imaging.Pdf.PdfCompressionSettings.DefaultSettings);
        page["Contents"] = Vintasoft.Imaging.Pdf.BasicTypes.PdfIndirectObject.Create(document, contentStream).GetReference();

        document.Save(outputPdfFilename);
    }
}

/// <summary>
/// Gets the basic object of specified type.
/// </summary>
/// <typeparam name="T">Type of basic object.</typeparam>
/// <param name="obj">The basic object.</param>
private static T GetBasicObject<T>(Vintasoft.Imaging.Pdf.BasicTypes.PdfBasicObject obj)
    where T : Vintasoft.Imaging.Pdf.BasicTypes.PdfBasicObject
{
    if (obj is T)
        return (T)obj;
    if (obj is Vintasoft.Imaging.Pdf.BasicTypes.PdfIndirectReference)
        return GetBasicObject<T>(
            Vintasoft.Imaging.Pdf.BasicTypes.PdfIndirectObject.GetByReference(((
                Vintasoft.Imaging.Pdf.BasicTypes.PdfIndirectReference)obj)));
    if (obj is Vintasoft.Imaging.Pdf.BasicTypes.PdfIndirectObject)
        return GetBasicObject<T>(((Vintasoft.Imaging.Pdf.BasicTypes.PdfIndirectObject)obj).Value);
    if (obj is Vintasoft.Imaging.Pdf.BasicTypes.PdfStream)
        return GetBasicObject<T>(((Vintasoft.Imaging.Pdf.BasicTypes.PdfStream)obj).Dictionary);
    return (T)obj;
}

''' <summary>
''' Creates a single page PDF document using only PDF basic types (basic PDF tree).
''' </summary>
''' <param name="outputPdfFilename">The output PDF filename.</param>
Public Shared Sub CreatePdfDocumentUseBasicTypes(outputPdfFilename As String)
    Using document As New Vintasoft.Imaging.Pdf.PdfDocument(Vintasoft.Imaging.Pdf.PdfFormat.Pdf_14)
        Dim catalog As Vintasoft.Imaging.Pdf.BasicTypes.PdfDictionary = GetBasicObject(Of Vintasoft.Imaging.Pdf.BasicTypes.PdfDictionary)(document.Catalog.BasicObject)

        Dim pages As Vintasoft.Imaging.Pdf.BasicTypes.PdfDictionary = GetBasicObject(Of Vintasoft.Imaging.Pdf.BasicTypes.PdfDictionary)(catalog("Pages"))

        pages("Count") = New Vintasoft.Imaging.Pdf.BasicTypes.PdfIntegerNumber(1)
        Dim page As New Vintasoft.Imaging.Pdf.BasicTypes.PdfDictionary(document)
        pages("Kids") = New Vintasoft.Imaging.Pdf.BasicTypes.PdfArray(document, Vintasoft.Imaging.Pdf.BasicTypes.PdfIndirectObject.Create(document, page).GetReference())

        page("Type") = New Vintasoft.Imaging.Pdf.BasicTypes.PdfName("Page")
        page("Parent") = catalog("Pages")
        page("MediaBox") = New Vintasoft.Imaging.Pdf.BasicTypes.PdfArray(document, Vintasoft.Imaging.Pdf.BasicTypes.PdfNumber.Create(0), Vintasoft.Imaging.Pdf.BasicTypes.PdfNumber.Create(0), Vintasoft.Imaging.Pdf.BasicTypes.PdfNumber.Create(300), Vintasoft.Imaging.Pdf.BasicTypes.PdfNumber.Create(400))

        Dim font As New Vintasoft.Imaging.Pdf.BasicTypes.PdfDictionary(document)
        font("Type") = New Vintasoft.Imaging.Pdf.BasicTypes.PdfName("Font")
        font("Subtype") = New Vintasoft.Imaging.Pdf.BasicTypes.PdfName("Type1")
        font("BaseFont") = New Vintasoft.Imaging.Pdf.BasicTypes.PdfName("Times-Roman")
        font("Encoding") = New Vintasoft.Imaging.Pdf.BasicTypes.PdfName("WinAnsiEncoding")

        Dim fontResources As New Vintasoft.Imaging.Pdf.BasicTypes.PdfDictionary(document)
        fontResources("F1") = Vintasoft.Imaging.Pdf.BasicTypes.PdfIndirectObject.Create(document, font).GetReference()
        Dim pageResources As New Vintasoft.Imaging.Pdf.BasicTypes.PdfDictionary(document)
        pageResources("Font") = fontResources
        page("Resources") = pageResources

        Dim content As String = "q /F1 20 Tf BT 100 200 Td (Hello World!) Tj ET Q"
        Dim contentStream As New Vintasoft.Imaging.Pdf.BasicTypes.PdfStream(document)
        contentStream.SetBytes(System.Text.Encoding.ASCII.GetBytes(content), Vintasoft.Imaging.Pdf.PdfCompression.None, Vintasoft.Imaging.Pdf.PdfCompressionSettings.DefaultSettings)
        page("Contents") = Vintasoft.Imaging.Pdf.BasicTypes.PdfIndirectObject.Create(document, contentStream).GetReference()

        document.Save(outputPdfFilename)
    End Using
End Sub

''' <summary>
''' Gets the basic object of specified type.
''' </summary>
''' <typeparam name="T">Type of basic object.</typeparam>
''' <param name="obj">The basic object.</param>
Private Shared Function GetBasicObject(Of T As Vintasoft.Imaging.Pdf.BasicTypes.PdfBasicObject)(obj As Vintasoft.Imaging.Pdf.BasicTypes.PdfBasicObject) As T
    If TypeOf obj Is T Then
        Return DirectCast(obj, T)
    End If
    If TypeOf obj Is Vintasoft.Imaging.Pdf.BasicTypes.PdfIndirectReference Then
        Return GetBasicObject(Of T)(Vintasoft.Imaging.Pdf.BasicTypes.PdfIndirectObject.GetByReference(DirectCast(obj, Vintasoft.Imaging.Pdf.BasicTypes.PdfIndirectReference)))
    End If
    If TypeOf obj Is Vintasoft.Imaging.Pdf.BasicTypes.PdfIndirectObject Then
        Return GetBasicObject(Of T)(DirectCast(obj, Vintasoft.Imaging.Pdf.BasicTypes.PdfIndirectObject).Value)
    End If
    If TypeOf obj Is Vintasoft.Imaging.Pdf.BasicTypes.PdfStream Then
        Return GetBasicObject(Of T)(DirectCast(obj, Vintasoft.Imaging.Pdf.BasicTypes.PdfStream).Dictionary)
    End If
    Return DirectCast(obj, T)
End Function

/// <summary>
/// Tests add/get custom data.
/// </summary>
public static void Test()
{
    // create PDF document
    using (Vintasoft.Imaging.Pdf.PdfDocument document = 
        new Vintasoft.Imaging.Pdf.PdfDocument("textCustomData.pdf", Vintasoft.Imaging.Pdf.PdfFormat.Pdf_14))
    {
        // add empty page to the PDF document
        Vintasoft.Imaging.Pdf.Tree.PdfPage page = document.Pages.Add(Vintasoft.Imaging.PaperSizeKind.A4);
        
        // add custom data to the PDF document catalog
        AddCustomStringData(document.Catalog, 
            "MyStringData", "Test String Value 1");                
        AddCustomStreamData(document.Catalog, 
            "MyStreamData", System.Text.Encoding.Unicode.GetBytes("Test Stream Data 1"));
        
        // add custom data to the PDF page
        AddCustomStringData(page, 
            "MyStringData", "Test String Value 2");
        AddCustomStreamData(page, 
            "MyStreamData", System.Text.Encoding.Unicode.GetBytes("Test Stream Data 2"));

        // save changes in PDF document
        document.SaveChanges();
    }

    // open PDF document
    using (Vintasoft.Imaging.Pdf.PdfDocument document = 
        new Vintasoft.Imaging.Pdf.PdfDocument("textCustomData.pdf"))
    {
        // read "/MyStringData" entry from the PDF document catalog
        System.Console.WriteLine(
            GetCustomStringData(document.Catalog, "MyStringData"));

        // read "/MyStreamData" entry from the PDF document catalog
        System.Console.WriteLine(
            System.Text.Encoding.Unicode.GetString(GetCustomStreamData(document.Catalog, "MyStreamData")));
        
        // read "/MyStringData" entry from PDF page
        System.Console.WriteLine(
            GetCustomStringData(document.Pages[0], "MyStringData"));
        
        // read "/MyStreamData" entry from PDF page
        System.Console.WriteLine(
            System.Text.Encoding.Unicode.GetString(GetCustomStreamData(document.Pages[0], "MyStreamData")));
    }
}       

/// <summary>
/// Adds the custom string data with the specified name to the specified PDF tree node.
/// </summary>
/// <param name="pdfTreeNode">The PDF tree node.</param>
/// <param name="dataName">The data name.</param>
/// <param name="dataValue">The data value.</param>
public static void AddCustomStringData(
    Vintasoft.Imaging.Pdf.Tree.PdfTreeNodeBase pdfTreeNode,
    string dataName,
    string dataValue)
{
    Vintasoft.Imaging.Pdf.BasicTypes.PdfDictionary dictionary = GetDictionary(pdfTreeNode);
    if (dictionary.ContainsKey(dataName))
        throw new System.ArgumentException(string.Format("Key '{0}' already exists.", dataName));
    dictionary[dataName] = new Vintasoft.Imaging.Pdf.BasicTypes.PdfString(dataValue);
}

/// <summary>
/// Returns the custom string data with the specified name from the specified PDF tree node.
/// </summary>
/// <param name="pdfTreeNode">The PDF tree node.</param>
/// <param name="dataName">The data name.</param>
/// <returns>The custom string data with the specified name from the specified PDF tree node.</returns>
public static string GetCustomStringData(Vintasoft.Imaging.Pdf.Tree.PdfTreeNodeBase pdfTreeNode, string dataName)
{
    Vintasoft.Imaging.Pdf.BasicTypes.PdfDictionary dictionary = GetDictionary(pdfTreeNode);
    if (dictionary.ContainsKey(dataName))
        return ((Vintasoft.Imaging.Pdf.BasicTypes.PdfString)dictionary[dataName]).ValueAsTextString;
    throw new System.ArgumentException(string.Format("Key '{0}' is not found.", dataName));
}

/// <summary>
/// Adds the custom stream data with the specified name to the specified PDF tree node.
/// </summary>
/// <param name="pdfTreeNode">The PDF tree node.</param>
/// <param name="dataName">The data name.</param>
/// <param name="dataValue">The data value.</param>
public static void AddCustomStreamData(
    Vintasoft.Imaging.Pdf.Tree.PdfTreeNodeBase pdfTreeNode,
    string dataName,
    byte[] dataValue)
{
    Vintasoft.Imaging.Pdf.BasicTypes.PdfDictionary dictionary = GetDictionary(pdfTreeNode);
    if (dictionary.ContainsKey(dataName))
        throw new System.ArgumentException(string.Format("Key '{0}' already exists.", dataName));
    // create a stream
    Vintasoft.Imaging.Pdf.BasicTypes.PdfStream stream = 
        new Vintasoft.Imaging.Pdf.BasicTypes.PdfStream(pdfTreeNode.Document);
    // write data, compressed with ZIP compression, to the stream
    stream.SetBytes(dataValue, Vintasoft.Imaging.Pdf.PdfCompression.Zip, 
        Vintasoft.Imaging.Pdf.PdfCompressionSettings.DefaultSettings);
    // create an indirect object from the stream
    Vintasoft.Imaging.Pdf.BasicTypes.PdfIndirectObject indirectObject = 
        Vintasoft.Imaging.Pdf.BasicTypes.PdfIndirectObject.Create(pdfTreeNode.Document, stream);
    // set the reference for the specified entry
    dictionary[dataName] = indirectObject.GetReference();
}

/// <summary>
/// Returns the custom stream data with specified name from specified tree node.
/// </summary>
/// <param name="pdfTreeNode">The PDF tree node.</param>
/// <param name="dataName">The data name.</param>
public static byte[] GetCustomStreamData(Vintasoft.Imaging.Pdf.Tree.PdfTreeNodeBase pdfTreeNode, string dataName)
{
    Vintasoft.Imaging.Pdf.BasicTypes.PdfDictionary dictionary = GetDictionary(pdfTreeNode);
    if (dictionary.ContainsKey(dataName))
    {
        Vintasoft.Imaging.Pdf.BasicTypes.PdfIndirectReference reference = 
            (Vintasoft.Imaging.Pdf.BasicTypes.PdfIndirectReference)dictionary[dataName];
        Vintasoft.Imaging.Pdf.BasicTypes.PdfIndirectObject indirectObject = 
            Vintasoft.Imaging.Pdf.BasicTypes.PdfIndirectObject.GetByReference(reference);
        Vintasoft.Imaging.Pdf.BasicTypes.PdfStream stream = 
            (Vintasoft.Imaging.Pdf.BasicTypes.PdfStream)indirectObject.Value;
        return stream.GetBytes();
    }
    throw new System.ArgumentException(string.Format("Key '{0}' is not found.", dataName));
}

/// <summary>
/// Returns the dictionary from PDF tree node.
/// </summary>
/// <param name="node">The node.</param>
private static Vintasoft.Imaging.Pdf.BasicTypes.PdfDictionary GetDictionary(
    Vintasoft.Imaging.Pdf.Tree.PdfTreeNodeBase node)
{
    Vintasoft.Imaging.Pdf.BasicTypes.PdfDictionary dictionary = 
        node.BasicObject as Vintasoft.Imaging.Pdf.BasicTypes.PdfDictionary;
    if (dictionary == null)
        throw new System.ArgumentException(
            string.Format("Node {0} is not a dictionary!", node.GetType().Name));
    return dictionary;
}

''' <summary>
''' Tests add/get custom data.
''' </summary>
Public Shared Sub Test()
    ' create PDF document
    Using document As New Vintasoft.Imaging.Pdf.PdfDocument("textCustomData.pdf", Vintasoft.Imaging.Pdf.PdfFormat.Pdf_14)
        ' add empty page to the PDF document
        Dim page As Vintasoft.Imaging.Pdf.Tree.PdfPage = document.Pages.Add(Vintasoft.Imaging.PaperSizeKind.A4)

        ' add custom data to the PDF document catalog
        AddCustomStringData(document.Catalog, "MyStringData", "Test String Value 1")
        AddCustomStreamData(document.Catalog, "MyStreamData", System.Text.Encoding.Unicode.GetBytes("Test Stream Data 1"))

        ' add custom data to the PDF page
        AddCustomStringData(page, "MyStringData", "Test String Value 2")
        AddCustomStreamData(page, "MyStreamData", System.Text.Encoding.Unicode.GetBytes("Test Stream Data 2"))

        ' save changes in PDF document
        document.SaveChanges()
    End Using

    ' open PDF document
    Using document As New Vintasoft.Imaging.Pdf.PdfDocument("textCustomData.pdf")
        ' read "/MyStringData" entry from the PDF document catalog
        System.Console.WriteLine(GetCustomStringData(document.Catalog, "MyStringData"))

        ' read "/MyStreamData" entry from the PDF document catalog
        System.Console.WriteLine(System.Text.Encoding.Unicode.GetString(GetCustomStreamData(document.Catalog, "MyStreamData")))

        ' read "/MyStringData" entry from PDF page
        System.Console.WriteLine(GetCustomStringData(document.Pages(0), "MyStringData"))

        ' read "/MyStreamData" entry from PDF page
        System.Console.WriteLine(System.Text.Encoding.Unicode.GetString(GetCustomStreamData(document.Pages(0), "MyStreamData")))
    End Using
End Sub

''' <summary>
''' Adds the custom string data with the specified name to the specified PDF tree node.
''' </summary>
''' <param name="pdfTreeNode">The PDF tree node.</param>
''' <param name="dataName">The data name.</param>
''' <param name="dataValue">The data value.</param>
Public Shared Sub AddCustomStringData(pdfTreeNode As Vintasoft.Imaging.Pdf.Tree.PdfTreeNodeBase, dataName As String, dataValue As String)
    Dim dictionary As Vintasoft.Imaging.Pdf.BasicTypes.PdfDictionary = GetDictionary(pdfTreeNode)
    If dictionary.ContainsKey(dataName) Then
        Throw New System.ArgumentException(String.Format("Key '{0}' already exists.", dataName))
    End If
    dictionary(dataName) = New Vintasoft.Imaging.Pdf.BasicTypes.PdfString(dataValue)
End Sub

''' <summary>
''' Returns the custom string data with the specified name from the specified PDF tree node.
''' </summary>
''' <param name="pdfTreeNode">The PDF tree node.</param>
''' <param name="dataName">The data name.</param>
''' <returns>The custom string data with the specified name from the specified PDF tree node.</returns>
Public Shared Function GetCustomStringData(pdfTreeNode As Vintasoft.Imaging.Pdf.Tree.PdfTreeNodeBase, dataName As String) As String
    Dim dictionary As Vintasoft.Imaging.Pdf.BasicTypes.PdfDictionary = GetDictionary(pdfTreeNode)
    If dictionary.ContainsKey(dataName) Then
        Return DirectCast(dictionary(dataName), Vintasoft.Imaging.Pdf.BasicTypes.PdfString).ValueAsTextString
    End If
    Throw New System.ArgumentException(String.Format("Key '{0}' is not found.", dataName))
End Function

''' <summary>
''' Adds the custom stream data with the specified name to the specified PDF tree node.
''' </summary>
''' <param name="pdfTreeNode">The PDF tree node.</param>
''' <param name="dataName">The data name.</param>
''' <param name="dataValue">The data value.</param>
Public Shared Sub AddCustomStreamData(pdfTreeNode As Vintasoft.Imaging.Pdf.Tree.PdfTreeNodeBase, dataName As String, dataValue As Byte())
    Dim dictionary As Vintasoft.Imaging.Pdf.BasicTypes.PdfDictionary = GetDictionary(pdfTreeNode)
    If dictionary.ContainsKey(dataName) Then
        Throw New System.ArgumentException(String.Format("Key '{0}' already exists.", dataName))
    End If
    ' create a stream
    Dim stream As New Vintasoft.Imaging.Pdf.BasicTypes.PdfStream(pdfTreeNode.Document)
    ' write data, compressed with ZIP compression, to the stream
    stream.SetBytes(dataValue, Vintasoft.Imaging.Pdf.PdfCompression.Zip, Vintasoft.Imaging.Pdf.PdfCompressionSettings.DefaultSettings)
    ' create an indirect object from the stream
    Dim indirectObject As Vintasoft.Imaging.Pdf.BasicTypes.PdfIndirectObject = Vintasoft.Imaging.Pdf.BasicTypes.PdfIndirectObject.Create(pdfTreeNode.Document, stream)
    ' set the reference for the specified entry
    dictionary(dataName) = indirectObject.GetReference()
End Sub

''' <summary>
''' Returns the custom stream data with specified name from specified tree node.
''' </summary>
''' <param name="pdfTreeNode">The PDF tree node.</param>
''' <param name="dataName">The data name.</param>
Public Shared Function GetCustomStreamData(pdfTreeNode As Vintasoft.Imaging.Pdf.Tree.PdfTreeNodeBase, dataName As String) As Byte()
    Dim dictionary As Vintasoft.Imaging.Pdf.BasicTypes.PdfDictionary = GetDictionary(pdfTreeNode)
    If dictionary.ContainsKey(dataName) Then
        Dim reference As Vintasoft.Imaging.Pdf.BasicTypes.PdfIndirectReference = DirectCast(dictionary(dataName), Vintasoft.Imaging.Pdf.BasicTypes.PdfIndirectReference)
        Dim indirectObject As Vintasoft.Imaging.Pdf.BasicTypes.PdfIndirectObject = Vintasoft.Imaging.Pdf.BasicTypes.PdfIndirectObject.GetByReference(reference)
        Dim stream As Vintasoft.Imaging.Pdf.BasicTypes.PdfStream = DirectCast(indirectObject.Value, Vintasoft.Imaging.Pdf.BasicTypes.PdfStream)
        Return stream.GetBytes()
    End If
    Throw New System.ArgumentException(String.Format("Key '{0}' is not found.", dataName))
End Function

''' <summary>
''' Returns the dictionary from PDF tree node.
''' </summary>
''' <param name="node">The node.</param>
Private Shared Function GetDictionary(node As Vintasoft.Imaging.Pdf.Tree.PdfTreeNodeBase) As Vintasoft.Imaging.Pdf.BasicTypes.PdfDictionary
    Dim dictionary As Vintasoft.Imaging.Pdf.BasicTypes.PdfDictionary = TryCast(node.BasicObject, Vintasoft.Imaging.Pdf.BasicTypes.PdfDictionary)
    If dictionary Is Nothing Then
        Throw New System.ArgumentException(String.Format("Node {0} is not a dictionary!", node.[GetType]().Name))
    End If
    Return dictionary
End Function