/// <summary>
/// Gets and prints information about all annotations of PDF page.
/// </summary>
/// <param name="pdfFileName">The filename of PDF document.</param>
public static void PrintAnnotationsInfo(string pdfFileName)
{
    // open PDF document
    using (Vintasoft.Imaging.Pdf.PdfDocument document =
        new Vintasoft.Imaging.Pdf.PdfDocument(pdfFileName))
    {
        // for each PDF page
        for (int pageIndex = 0; pageIndex < document.Pages.Count; pageIndex++)
        {
            // get PDF page
            Vintasoft.Imaging.Pdf.Tree.PdfPage page = document.Pages[pageIndex];
            // get a collection of annotations of PDF page
            Vintasoft.Imaging.Pdf.Tree.Annotations.PdfAnnotationList annotations = page.Annotations;
            if (annotations == null)
            {
                System.Console.WriteLine("Page {0}: no annotations.", pageIndex + 1);
            }
            else
            {
                // print the page index and count of annotations
                System.Console.WriteLine("Page {0} Annotation count: {1}", pageIndex + 1, annotations.Count);
                // for each annotation
                foreach (Vintasoft.Imaging.Pdf.Tree.Annotations.PdfAnnotation annotation in annotations)
                {
                    // print information about annotation
                    System.Console.WriteLine("Annotation:");
                    System.Console.WriteLine("           Name: \"{0}\"", annotation.Name);
                    System.Console.WriteLine(" Title (Author): \"{0}\"", annotation.Title);
                    System.Console.WriteLine("        Subject: \"{0}\"", annotation.Subject);
                    System.Console.WriteLine("       Contents: \"{0}\"", annotation.Contents);
                    System.Console.WriteLine("AppearanceState: \"{0}\"", annotation.AppearanceState);
                    System.Console.WriteLine("       Modified: {0}", annotation.Modified);
                    System.Console.WriteLine("          Flags: {0}", annotation.Flags);
                    System.Console.WriteLine();
                }
            }
        }
    }
}

''' <summary>
''' Gets and prints information about all annotations of PDF page.
''' </summary>
''' <param name="pdfFileName">The filename of PDF document.</param>
Public Shared Sub PrintAnnotationsInfo(pdfFileName As String)
    ' open PDF document
    Using document As New Vintasoft.Imaging.Pdf.PdfDocument(pdfFileName)
        ' for each PDF page
        For pageIndex As Integer = 0 To document.Pages.Count - 1
            ' get PDF page
            Dim page As Vintasoft.Imaging.Pdf.Tree.PdfPage = document.Pages(pageIndex)
            ' get a collection of annotations of PDF page
            Dim annotations As Vintasoft.Imaging.Pdf.Tree.Annotations.PdfAnnotationList = page.Annotations
            If annotations Is Nothing Then
                System.Console.WriteLine("Page {0}: no annotations.", pageIndex + 1)
            Else
                ' print the page index and count of annotations
                System.Console.WriteLine("Page {0} Annotation count: {1}", pageIndex + 1, annotations.Count)
                ' for each annotation
                For Each annotation As Vintasoft.Imaging.Pdf.Tree.Annotations.PdfAnnotation In annotations
                    ' print information about annotation
                    System.Console.WriteLine("Annotation:")
                    System.Console.WriteLine("           Name: ""{0}""", annotation.Name)
                    System.Console.WriteLine(" Title (Author): ""{0}""", annotation.Title)
                    System.Console.WriteLine("        Subject: ""{0}""", annotation.Subject)
                    System.Console.WriteLine("       Contents: ""{0}""", annotation.Contents)
                    System.Console.WriteLine("AppearanceState: ""{0}""", annotation.AppearanceState)
                    System.Console.WriteLine("       Modified: {0}", annotation.Modified)
                    System.Console.WriteLine("          Flags: {0}", annotation.Flags)
                    System.Console.WriteLine()
                Next
            End If
        Next
    End Using
End Sub

/// <summary>
/// Creates an annotation, which consists from red rectangle.
/// </summary>
/// <param name="page">The page.</param>
/// <returns>The created annotation.</returns>
public static Vintasoft.Imaging.Pdf.Tree.Annotations.PdfAnnotation CreatePdfAnnotation(
    Vintasoft.Imaging.Pdf.Tree.PdfPage page)
{
    // create a rectangular annotation
    Vintasoft.Imaging.Pdf.Tree.Annotations.PdfSquareAnnotation annotation = 
        new Vintasoft.Imaging.Pdf.Tree.Annotations.PdfSquareAnnotation(page);
    // set interior color
    annotation.InteriorColor = System.Drawing.Color.Red;
    // set rectangle
    annotation.Rectangle = new System.Drawing.RectangleF(40, 40, 160, 80);
    // create graphics for normal appearance
    using (Vintasoft.Imaging.Pdf.Drawing.PdfGraphics pdfGraphics = annotation.CreateNormalAppearanceGraphics())
    {
        // draw an appearance of the annotation
        pdfGraphics.FillRectangle(
            new Vintasoft.Imaging.Pdf.Drawing.PdfBrush(System.Drawing.Color.Red), 
            0, 0, 
            annotation.Rectangle.Width, annotation.Rectangle.Height);
    }

    // return created annotation
    return annotation;
}

''' <summary>
''' Creates an annotation, which consists from red rectangle.
''' </summary>
''' <param name="page">The page.</param>
''' <returns>The created annotation.</returns>
Public Shared Function CreatePdfAnnotation(page As Vintasoft.Imaging.Pdf.Tree.PdfPage) As Vintasoft.Imaging.Pdf.Tree.Annotations.PdfAnnotation
    ' create a rectangular annotation
    Dim annotation As New Vintasoft.Imaging.Pdf.Tree.Annotations.PdfSquareAnnotation(page)
    ' set interior color
    annotation.InteriorColor = System.Drawing.Color.Red
    ' set rectangle
    annotation.Rectangle = New System.Drawing.RectangleF(40, 40, 160, 80)
    ' create graphics for normal appearance
    Using pdfGraphics As Vintasoft.Imaging.Pdf.Drawing.PdfGraphics = annotation.CreateNormalAppearanceGraphics()
        ' draw an appearance of the annotation
        pdfGraphics.FillRectangle(New Vintasoft.Imaging.Pdf.Drawing.PdfBrush(System.Drawing.Color.Red), 0, 0, annotation.Rectangle.Width, annotation.Rectangle.Height)
    End Using

    ' return created annotation
    Return annotation
End Function

/// <summary>
/// Creates a Line annotation and adds it onto PDF page.
/// </summary>
/// <param name="pdfFilename">The filename of PDF document.</param>
public static void AddLineAnnotationOntoPage(string pdfFilename)
{
    // open PDF document
    using (Vintasoft.Imaging.Pdf.PdfDocument pdfDocument = new Vintasoft.Imaging.Pdf.PdfDocument(pdfFilename))
    {
        // get first page of the document
        Vintasoft.Imaging.Pdf.Tree.PdfPage page = pdfDocument.Pages[0];
        // create line annotation
        Vintasoft.Imaging.Pdf.Tree.Annotations.PdfLineAnnotation lineAnnotation = 
            new Vintasoft.Imaging.Pdf.Tree.Annotations.PdfLineAnnotation(page);
        // set color of the annotation
        lineAnnotation.Color = System.Drawing.Color.Green;
        // set rectangle of the annotation
        lineAnnotation.Rectangle = page.CropBox;
        // set start point of the annotation
        lineAnnotation.StartPoint = new System.Drawing.PointF(0, 0);
        // set end point of the annotation
        lineAnnotation.EndPoint = new System.Drawing.PointF(page.CropBox.Width, page.CropBox.Height);
        // create graphics for normal appearance
        using (Vintasoft.Imaging.Pdf.Drawing.PdfGraphics pdfGraphics = lineAnnotation.CreateNormalAppearanceGraphics())
        {
            // draw appearance of the annotation
            pdfGraphics.DrawLine(new Vintasoft.Imaging.Pdf.Drawing.PdfPen(System.Drawing.Color.Green, 3f),
                0, 0, lineAnnotation.Rectangle.Width, lineAnnotation.Rectangle.Height);
        }
        // if there is no annotations
        if (page.Annotations == null)
            // create collection of annotations of the page
            page.Annotations = new Vintasoft.Imaging.Pdf.Tree.Annotations.PdfAnnotationList(pdfDocument);
        // add the annotation to the collection
        page.Annotations.Add(lineAnnotation);
        // save changes to the source
        pdfDocument.SaveChanges();
    }
}

''' <summary>
''' Creates a Line annotation and adds it onto PDF page.
''' </summary>
''' <param name="pdfFilename">The filename of PDF document.</param>
Public Shared Sub AddLineAnnotationOntoPage(pdfFilename As String)
    ' open PDF document
    Using pdfDocument As New Vintasoft.Imaging.Pdf.PdfDocument(pdfFilename)
        ' get first page of the document
        Dim page As Vintasoft.Imaging.Pdf.Tree.PdfPage = pdfDocument.Pages(0)
        ' create line annotation
        Dim lineAnnotation As New Vintasoft.Imaging.Pdf.Tree.Annotations.PdfLineAnnotation(page)
        ' set color of the annotation
        lineAnnotation.Color = System.Drawing.Color.Green
        ' set rectangle of the annotation
        lineAnnotation.Rectangle = page.CropBox
        ' set start point of the annotation
        lineAnnotation.StartPoint = New System.Drawing.PointF(0, 0)
        ' set end point of the annotation
        lineAnnotation.EndPoint = New System.Drawing.PointF(page.CropBox.Width, page.CropBox.Height)
        ' create graphics for normal appearance
        Using pdfGraphics As Vintasoft.Imaging.Pdf.Drawing.PdfGraphics = lineAnnotation.CreateNormalAppearanceGraphics()
            ' draw appearance of the annotation
            pdfGraphics.DrawLine(New Vintasoft.Imaging.Pdf.Drawing.PdfPen(System.Drawing.Color.Green, 3F), 0, 0, lineAnnotation.Rectangle.Width, lineAnnotation.Rectangle.Height)
        End Using
        ' if there is no annotations
        If page.Annotations Is Nothing Then
            ' create collection of annotations of the page
            page.Annotations = New Vintasoft.Imaging.Pdf.Tree.Annotations.PdfAnnotationList(pdfDocument)
        End If
        ' add the annotation to the collection
        page.Annotations.Add(lineAnnotation)
        ' save changes to the source
        pdfDocument.SaveChanges()
    End Using
End Sub

/// <summary>
/// Removes the first annotation from PDF page
/// if it is a link annotation.
/// </summary>
/// <param name="page">The page of PDF document.</param>
public static bool RemoveAnnotationFromPdfPage(Vintasoft.Imaging.Pdf.Tree.PdfPage page)
{
    // if annotations exist
    if (page.Annotations != null && page.Annotations.Count > 0)
    {
        // if contents of the first annotation if it is a link
        if (page.Annotations[0] is Vintasoft.Imaging.Pdf.Tree.Annotations.PdfLinkAnnotation)
        {
            // remove the annotation
            page.Annotations.RemoveAt(0);
            return true;
        }
    }

    return false;
}

''' <summary>
''' Removes the first annotation from PDF page
''' if it is a link annotation.
''' </summary>
''' <param name="page">The page of PDF document.</param>
Public Shared Function RemoveAnnotationFromPdfPage(page As Vintasoft.Imaging.Pdf.Tree.PdfPage) As Boolean
    ' if annotations exist
    If page.Annotations IsNot Nothing AndAlso page.Annotations.Count > 0 Then
        ' if contents of the first annotation if it is a link
        If TypeOf page.Annotations(0) Is Vintasoft.Imaging.Pdf.Tree.Annotations.PdfLinkAnnotation Then
            ' remove the annotation
            page.Annotations.RemoveAt(0)
            Return True
        End If
    End If

    Return False
End Function

/// <summary>
/// Demonstrates how to prints comments of specified PDF document.
/// </summary>
public class PdfAnnotationCommentExample
{
    /// <summary>
    /// Prints comments of specified PDF document.
    /// </summary>
    /// <param name="pdfFilename">The PDF filename.</param>
    public static void PrintComments(string pdfFilename)
    {
        // create an image collection
        using (Vintasoft.Imaging.ImageCollection images = new Vintasoft.Imaging.ImageCollection())
        {
            // add PDF document to the image collection
            images.Add(pdfFilename);

            // create PDF annotation comment controller
            using (Vintasoft.Imaging.Annotation.Comments.Pdf.ImageCollectionPdfAnnotationCommentController pdfAnnotationCommentController =
                new Vintasoft.Imaging.Annotation.Comments.Pdf.ImageCollectionPdfAnnotationCommentController())
            {
                // specify that PDF annotation comment controller is associated with image collection
                pdfAnnotationCommentController.Images = images;

                // print comments from PDF annotation comment controller
                PrintComments(pdfAnnotationCommentController);
            }

            // clear and dispose images
            images.ClearAndDisposeItems();
        }
    }

    /// <summary>
    /// Prints comments from specified comment controller.
    /// </summary>
    /// <param name="commentController">The comment controller.</param>
    public static void PrintComments(Vintasoft.Imaging.Annotation.Comments.ImageCollectionCommentController commentController)
    {
        // for each image
        for (int i = 0; i < commentController.Images.Count; i++)
        {
            Vintasoft.Imaging.VintasoftImage image = commentController.Images[i];

            // get comment collection, which is associated with image/PDF page
            Vintasoft.Imaging.Annotation.Comments.CommentCollection comments = commentController.GetComments(image);
            // if comments are found
            if (comments != null && comments.Count > 0)
            {
                System.Console.WriteLine(string.Format("Page {0}:", i + 1));

                // for each comment
                foreach (Vintasoft.Imaging.Annotation.Comments.Comment comment in comments)
                {
                    // print comment
                    PrintComment(comment, 0);
                }
            }
        }
    }

    /// <summary>
    /// Prints the comment.
    /// </summary>
    /// <param name="comment">The comment.</param>
    /// <param name="replyLevel">The reply level.</param>
    private static void PrintComment(Vintasoft.Imaging.Annotation.Comments.Comment comment, int replyLevel)
    {
        // print comment
        System.Console.Write(string.Empty.PadLeft(replyLevel * 4));
        System.Console.WriteLine(string.Format("[{0}] {1}: {2} ({3})",comment.Type, comment.UserName, comment.Text, comment.ModifyDate));

        // if comment has replies
        if (comment.Replies != null)
        {
            // print replies
            foreach (Vintasoft.Imaging.Annotation.Comments.Comment reply in comment.Replies)
                PrintComment(reply, replyLevel + 1);
        }
    }

}

''' <summary>
''' Demonstrates how to prints comments of specified PDF document.
''' </summary>
Public Class PdfAnnotationCommentExample
    ''' <summary>
    ''' Prints comments of specified PDF document.
    ''' </summary>
    ''' <param name="pdfFilename">The PDF filename.</param>
    Public Shared Sub PrintComments(pdfFilename As String)
        ' create an image collection
        Using images As New Vintasoft.Imaging.ImageCollection()
            ' add PDF document to the image collection
            images.Add(pdfFilename)

            ' create PDF annotation comment controller
            Using pdfAnnotationCommentController As New Vintasoft.Imaging.Annotation.Comments.Pdf.ImageCollectionPdfAnnotationCommentController()
                ' specify that PDF annotation comment controller is associated with image collection
                pdfAnnotationCommentController.Images = images

                ' print comments from PDF annotation comment controller
                PrintComments(pdfAnnotationCommentController)
            End Using

            ' clear and dispose images
            images.ClearAndDisposeItems()
        End Using
    End Sub

    ''' <summary>
    ''' Prints comments from specified comment controller.
    ''' </summary>
    ''' <param name="commentController">The comment controller.</param>
    Public Shared Sub PrintComments(commentController As Vintasoft.Imaging.Annotation.Comments.ImageCollectionCommentController)
        ' for each image
        For i As Integer = 0 To commentController.Images.Count - 1
            Dim image As Vintasoft.Imaging.VintasoftImage = commentController.Images(i)

            ' get comment collection, which is associated with image/PDF page
            Dim comments As Vintasoft.Imaging.Annotation.Comments.CommentCollection = commentController.GetComments(image)
            ' if comments are found
            If comments IsNot Nothing AndAlso comments.Count > 0 Then
                System.Console.WriteLine(String.Format("Page {0}:", i + 1))

                ' for each comment
                For Each comment As Vintasoft.Imaging.Annotation.Comments.Comment In comments
                    ' print comment
                    PrintComment(comment, 0)
                Next
            End If
        Next
    End Sub

    ''' <summary>
    ''' Prints the comment.
    ''' </summary>
    ''' <param name="comment">The comment.</param>
    ''' <param name="replyLevel">The reply level.</param>
    Private Shared Sub PrintComment(comment As Vintasoft.Imaging.Annotation.Comments.Comment, replyLevel As Integer)
        ' print comment
        System.Console.Write(String.Empty.PadLeft(replyLevel * 4))
        System.Console.WriteLine(String.Format("[{0}] {1}: {2} ({3})", comment.Type, comment.UserName, comment.Text, comment.ModifyDate))

        ' if comment has replies
        If comment.Replies IsNot Nothing Then
            ' print replies
            For Each reply As Vintasoft.Imaging.Annotation.Comments.Comment In comment.Replies
                PrintComment(reply, replyLevel + 1)
            Next
        End If
    End Sub

End Class