PDF: Navigating PDF document

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PDF bookmarks

A PDF document may include a table of contents. The table of contents may be displayed in a way to provide the user with ability to move through the document using mouse and keyboard. The table of content has tree-structure and is called Bookmarks.

A group of bookmarks is defined using PdfBookmarkCollection class. Single bookmark is defined using PdfBookmark class.

Getting bookmarks as tree structure

A document bookmarks can be get using PdfDocument.Bookmarks property.

Here is C#/VB.NET code that demonstrates how to display the information about bookmarks tree of PDF document:

/// <summary>
/// Prints information about the bookmark collection of specified PDF document.
/// </summary>
/// <param name="filename">The filename of PDF document.</param>
public static void PrintBookmarks(string filename)
{
    // open PDF document in read-only mode
    Vintasoft.Imaging.Pdf.PdfDocument document = 
        new Vintasoft.Imaging.Pdf.PdfDocument(filename, true);

    // print Bookrmarks collection
    PrintBookmarkCollection(document.Bookmarks, "");

    // close document
    document.Dispose();
}

/// <summary>
/// Prints information about the bookmark collection of PDF document.
/// </summary>
public static void PrintBookmarkCollection(
    Vintasoft.Imaging.Pdf.Tree.PdfBookmarkCollection bookmarks, string indent)
{
    // for each bookmarks in the collection
    for (int i = 0; i < bookmarks.Count; i++)
    {
        Vintasoft.Imaging.Pdf.Tree.PdfBookmark bookmark = bookmarks[i];

        // print indent
        System.Console.Write(indent);

        // print status of child bookmarks
        System.Console.Write(bookmark.ChildBookmarks.Count > 0 ? "+" : "-");

        // print title
        System.Console.Write(bookmark.Title);

        // find destination page
        Vintasoft.Imaging.Pdf.Tree.PdfDestinationBase destination = bookmark.Destination;
        if (destination == null)
        {
            if (bookmark.Action != null && 
                bookmark.Action is Vintasoft.Imaging.Pdf.Tree.PdfGotoAction)
            {
                destination = ((Vintasoft.Imaging.Pdf.Tree.PdfGotoAction)bookmark.Action).Destination;
            }
        }
        if (destination != null)
        {
            // print destination page number
            int pageIndex = bookmark.Document.Pages.IndexOf(destination.Page);
            System.Console.Write(": Page " + (pageIndex + 1).ToString());
        }

        // print bookmark Flags
        if (bookmark.Flags != Vintasoft.Imaging.Pdf.Tree.PdfBookmarkFlags.None)
            System.Console.Write(" (" + bookmark.Flags + ")");
        System.Console.WriteLine();

        // print child bookmarks
        PrintBookmarkCollection(bookmark.ChildBookmarks, indent + "  ");
    }
}

VB.NET

''' <summary>
''' Prints information about the bookmark collection of specified PDF document.
''' </summary>
''' <param name="filename">The filename of PDF document.</param>
Public Shared Sub PrintBookmarks(filename As String)
    ' open PDF document in read-only mode
    Dim document As New Vintasoft.Imaging.Pdf.PdfDocument(filename, True)

    ' print Bookrmarks collection
    PrintBookmarkCollection(document.Bookmarks, "")

    ' close document
    document.Dispose()
End Sub

''' <summary>
''' Prints information about the bookmark collection of PDF document.
''' </summary>
Public Shared Sub PrintBookmarkCollection(bookmarks As Vintasoft.Imaging.Pdf.Tree.PdfBookmarkCollection, indent As String)
    ' for each bookmarks in the collection
    For i As Integer = 0 To bookmarks.Count - 1
        Dim bookmark As Vintasoft.Imaging.Pdf.Tree.PdfBookmark = bookmarks(i)

        ' print indent
        System.Console.Write(indent)

        ' print status of child bookmarks
        System.Console.Write(If(bookmark.ChildBookmarks.Count > 0, "+", "-"))

        ' print title
        System.Console.Write(bookmark.Title)

        ' find destination page
        Dim destination As Vintasoft.Imaging.Pdf.Tree.PdfDestinationBase = bookmark.Destination
        If destination Is Nothing Then
            If bookmark.Action IsNot Nothing AndAlso TypeOf bookmark.Action Is Vintasoft.Imaging.Pdf.Tree.PdfGotoAction Then
                destination = DirectCast(bookmark.Action, Vintasoft.Imaging.Pdf.Tree.PdfGotoAction).Destination
            End If
        End If
        If destination IsNot Nothing Then
            ' print destination page number
            Dim pageIndex As Integer = bookmark.Document.Pages.IndexOf(destination.Page)
            System.Console.Write(": Page " & (pageIndex + 1).ToString())
        End If

        ' print bookmark Flags
        If bookmark.Flags <> Vintasoft.Imaging.Pdf.Tree.PdfBookmarkFlags.None Then
            System.Console.Write(" (" & Convert.ToString(bookmark.Flags) & ")")
        End If
        System.Console.WriteLine()

        ' print child bookmarks
        PrintBookmarkCollection(bookmark.ChildBookmarks, indent & "  ")
    Next
End Sub

Add new bookmark

To add a bookmark is necessary to do the following:

Create a bookmark
Define actions associated with the bookmark
Add a bookmark into bookmarks tree

Here is C#/VB.NET code that demonstrates how to add new bookmarks into PDF document:

/// <summary>
/// Creates bookmarks in PDF document.
/// </summary>
/// <param name="pdfFilename">The filename of PDF document.</param>
public static void CreateBookmarks(string pdfFilename)
{
    // open PDF document in read-write mode
    Vintasoft.Imaging.Pdf.PdfDocument document = 
        new Vintasoft.Imaging.Pdf.PdfDocument(pdfFilename);

    // if PDF document does not contain bookmark collection
    if (document.Bookmarks == null)
        // create bookmark collection of PDF document
        document.Bookmarks = 
            new Vintasoft.Imaging.Pdf.Tree.PdfBookmarkCollection(document);

    // get bookmarks collection
    Vintasoft.Imaging.Pdf.Tree.PdfBookmarkCollection bookmarks = document.Bookmarks;

    if (bookmarks.Count > 1)
    {
        // delete first bookmark
        bookmarks.RemoveAt(0);
        // delete last bookmark
        bookmarks.RemoveAt(bookmarks.Count - 1);
    }

    // create first bookmark
    Vintasoft.Imaging.Pdf.Tree.PdfBookmark firstBookmark = 
        new Vintasoft.Imaging.Pdf.Tree.PdfBookmark(document);
    firstBookmark.Title = "First Page";
    firstBookmark.Flags = Vintasoft.Imaging.Pdf.Tree.PdfBookmarkFlags.Bold;
    firstBookmark.Destination = new Vintasoft.Imaging.Pdf.Tree.PdfDestinationFit(document, document.Pages[0]);

    // create last bookmark
    Vintasoft.Imaging.Pdf.Tree.PdfBookmark lastBookmark = 
        new Vintasoft.Imaging.Pdf.Tree.PdfBookmark(document);
    lastBookmark.Title = "Last Page";
    lastBookmark.Flags = Vintasoft.Imaging.Pdf.Tree.PdfBookmarkFlags.Bold;
    lastBookmark.Destination = 
        new Vintasoft.Imaging.Pdf.Tree.PdfDestinationFit(document, document.Pages[document.Pages.Count - 1]);

    // insert first bookmark
    bookmarks.Insert(0, firstBookmark);

    // add last bookmark
    bookmarks.Add(lastBookmark);

    // save document
    document.SaveChanges();

    // close document
    document.Dispose();
}

VB.NET

''' <summary>
''' Creates bookmarks in PDF document.
''' </summary>
''' <param name="pdfFilename">The filename of PDF document.</param>
Public Shared Sub CreateBookmarks(pdfFilename As String)
    ' open PDF document in read-write mode
    Dim document As New Vintasoft.Imaging.Pdf.PdfDocument(pdfFilename)

    ' if PDF document does not contain bookmark collection
    If document.Bookmarks Is Nothing Then
        ' create bookmark collection of PDF document
        document.Bookmarks = New Vintasoft.Imaging.Pdf.Tree.PdfBookmarkCollection(document)
    End If

    ' get bookmarks collection
    Dim bookmarks As Vintasoft.Imaging.Pdf.Tree.PdfBookmarkCollection = document.Bookmarks

    If bookmarks.Count > 1 Then
        ' delete first bookmark
        bookmarks.RemoveAt(0)
        ' delete last bookmark
        bookmarks.RemoveAt(bookmarks.Count - 1)
    End If

    ' create first bookmark
    Dim firstBookmark As New Vintasoft.Imaging.Pdf.Tree.PdfBookmark(document)
    firstBookmark.Title = "First Page"
    firstBookmark.Flags = Vintasoft.Imaging.Pdf.Tree.PdfBookmarkFlags.Bold
    firstBookmark.Destination = New Vintasoft.Imaging.Pdf.Tree.PdfDestinationFit(document, document.Pages(0))

    ' create last bookmark
    Dim lastBookmark As New Vintasoft.Imaging.Pdf.Tree.PdfBookmark(document)
    lastBookmark.Title = "Last Page"
    lastBookmark.Flags = Vintasoft.Imaging.Pdf.Tree.PdfBookmarkFlags.Bold
    lastBookmark.Destination = New Vintasoft.Imaging.Pdf.Tree.PdfDestinationFit(document, document.Pages(document.Pages.Count - 1))

    ' insert first bookmark
    bookmarks.Insert(0, firstBookmark)

    ' add last bookmark
    bookmarks.Add(lastBookmark)

    ' save document
    document.SaveChanges()

    ' close document
    document.Dispose()
End Sub

Change bookmark

To change a bookmark is necessary to do the following:

Find the bookmark that should be changed
Change the bookmark using its properties

Here is C#/VB.NET code that demonstrates how to change text of bookmark:

/// <summary>
/// Changes title of the first bookmark of PDF document.
/// </summary>
/// <param name="pdfFilename">The filename of PDF document.</param>
public static void ChangeFirstBookmarkTitle(string pdfFilename)
{
    // open PDF document
    using (Vintasoft.Imaging.Pdf.PdfDocument document = 
        new Vintasoft.Imaging.Pdf.PdfDocument(pdfFilename))
    {
        // get the first bookmark of PDF document
        Vintasoft.Imaging.Pdf.Tree.PdfBookmark bookmark = document.Bookmarks[0];
        // change title of bookmark
        bookmark.Title = "First bookmark";

        // save changes to a file
        document.SaveChanges();
    }
}

VB.NET

''' <summary>
''' Changes title of the first bookmark of PDF document.
''' </summary>
''' <param name="pdfFilename">The filename of PDF document.</param>
Public Shared Sub ChangeFirstBookmarkTitle(pdfFilename As String)
    ' open PDF document
    Using document As New Vintasoft.Imaging.Pdf.PdfDocument(pdfFilename)
        ' get the first bookmark of PDF document
        Dim bookmark As Vintasoft.Imaging.Pdf.Tree.PdfBookmark = document.Bookmarks(0)
        ' change title of bookmark
        bookmark.Title = "First bookmark"

        ' save changes to a file
        document.SaveChanges()
    End Using
End Sub

Remove bookmark

To remove a bookmark is necessary to do the following:

Find the bookmark that should be removed
Call the PdfBookmark.Remove method for removing the bookmark OR call the PdfBookmarkCollection.Remove method of parent bookmark

Here is C#/VB.NET code that demonstrates how to remove all bookmarks from PDF document:

/// <summary>
/// Removes all bookmarks of PDF document.
/// </summary>
/// <param name="pdfFilename">The filename of PDF document.</param>
public static void RemoveAllBookmarks(string pdfFilename)
{
    // open PDF document
    using (Vintasoft.Imaging.Pdf.PdfDocument document = 
        new Vintasoft.Imaging.Pdf.PdfDocument(pdfFilename))
    {
        // get the collection of bookmark of PDF document
        Vintasoft.Imaging.Pdf.Tree.PdfBookmarkCollection bookmarks = document.Bookmarks;

        // if PDF document has bookmarks
        if (bookmarks != null)
            // clear bookmarks of PDF document
            bookmarks.Clear();

        // save changes to a file
        document.SaveChanges();
    }
}

VB.NET

''' <summary>
''' Removes all bookmarks of PDF document.
''' </summary>
''' <param name="pdfFilename">The filename of PDF document.</param>
Public Shared Sub RemoveAllBookmarks(pdfFilename As String)
    ' open PDF document
    Using document As New Vintasoft.Imaging.Pdf.PdfDocument(pdfFilename)
        ' get the collection of bookmark of PDF document
        Dim bookmarks As Vintasoft.Imaging.Pdf.Tree.PdfBookmarkCollection = document.Bookmarks

        ' if PDF document has bookmarks
        If bookmarks IsNot Nothing Then
            ' clear bookmarks of PDF document
            bookmarks.Clear()
        End If

        ' save changes to a file
        document.SaveChanges()
    End Using
End Sub

Action of bookmark

Any bookmark can have an action, which will be performed when the bookmark is selected.

Here is C#/VB.NET code that demonstrates how to assign an action to bookmark:

/// <summary>
/// Changes action of the first bookmark of PDF document.
/// </summary>
/// <param name="pdfFilename">The filename of PDF document.</param>
public static void ChangeFirstBookmarkAction(string pdfFilename)
{
    // open PDF document
    using (Vintasoft.Imaging.Pdf.PdfDocument document = 
        new Vintasoft.Imaging.Pdf.PdfDocument(pdfFilename))
    {
        // create goto action to the last page of PDF document
        Vintasoft.Imaging.Pdf.Tree.PdfDestinationFit dest = 
            new Vintasoft.Imaging.Pdf.Tree.PdfDestinationFit(document, document.Pages[document.Pages.Count - 1]);
        Vintasoft.Imaging.Pdf.Tree.PdfGotoAction newAction = 
            new Vintasoft.Imaging.Pdf.Tree.PdfGotoAction(dest);
        
        // get the first bookmark of PDF document
        Vintasoft.Imaging.Pdf.Tree.PdfBookmark bookmark = document.Bookmarks[0];
        // change the action of bookmark
        bookmark.Action = newAction;

        // save changes to a file
        document.SaveChanges();
    }
}

VB.NET

''' <summary>
''' Changes action of the first bookmark of PDF document.
''' </summary>
''' <param name="pdfFilename">The filename of PDF document.</param>
Public Shared Sub ChangeFirstBookmarkAction(pdfFilename As String)
    ' open PDF document
    Using document As New Vintasoft.Imaging.Pdf.PdfDocument(pdfFilename)
        ' create goto action to the last page of PDF document
        Dim dest As New Vintasoft.Imaging.Pdf.Tree.PdfDestinationFit(document, document.Pages(document.Pages.Count - 1))
        Dim newAction As New Vintasoft.Imaging.Pdf.Tree.PdfGotoAction(dest)

        ' get the first bookmark of PDF document
        Dim bookmark As Vintasoft.Imaging.Pdf.Tree.PdfBookmark = document.Bookmarks(0)
        ' change the action of bookmark
        bookmark.Action = newAction

        ' save changes to a file
        document.SaveChanges()
    End Using
End Sub

Embedded thumbnails of PDF pages

PDF pages may have embedded its own thumbnail. In most cases the embedded thumbnail is used for image-only pages, i.e. a page which represents a scanned image.

Embedded thumbnail can be obtained using PdfPage.Thumbnail property.

Also a page thumbnail can be obtained using PdfPage.GetThumbnail method. The method returns an embedded thumbnail if the embedded thumbnail exists and meets the requested dimensions. Otherwise, the method generates the page thumbnail dynamically.

Create embedded thumbnails of pages

An embedded thumbnail of page can be created using PdfPage.CreateThumbnail method. Embedded thumbnails of all pages can be created using PdfPageCollection.CreateThumbnails method.

Here is C#/VB.NET code that demonstrates how to create an embedded thumbnail of specified page:

/// <summary>
/// Creates an embedded thumbnail of PDF page.
/// </summary>
/// <param name="pdfFilename">The filename of PDF document.</param>
/// <param name="pageIndex">Index of PDF page.</param>
public static void CreateEmbeddedThumbnailOfPdfPage(string pdfFilename, int pageIndex)
{
    // open PDF document in read-write mode
    Vintasoft.Imaging.Pdf.PdfDocument document = 
        new Vintasoft.Imaging.Pdf.PdfDocument(pdfFilename);

    // get the page at the specified index
    Vintasoft.Imaging.Pdf.Tree.PdfPage page = document.Pages[pageIndex];

    // renderer thumbnail with size 128 x 128 pixels
    using (Vintasoft.Imaging.VintasoftImage pageThumbnail = page.Render(128, 128))
    {
        // set page thumbnail
        page.Thumbnail = new Vintasoft.Imaging.Pdf.Tree.PdfImageResource(
            document, pageThumbnail, Vintasoft.Imaging.Pdf.PdfCompression.Jpeg);
    }

    // save changes
    document.SaveChanges();

    // close document
    document.Dispose();
}

VB.NET

''' <summary>
''' Creates an embedded thumbnail of PDF page.
''' </summary>
''' <param name="pdfFilename">The filename of PDF document.</param>
''' <param name="pageIndex">Index of PDF page.</param>
Public Shared Sub CreateEmbeddedThumbnailOfPdfPage(pdfFilename As String, pageIndex As Integer)
    ' open PDF document in read-write mode
    Dim document As New Vintasoft.Imaging.Pdf.PdfDocument(pdfFilename)

    ' get the page at the specified index
    Dim page As Vintasoft.Imaging.Pdf.Tree.PdfPage = document.Pages(pageIndex)

    ' renderer thumbnail with size 128 x 128 pixels
    Using pageThumbnail As Vintasoft.Imaging.VintasoftImage = page.Render(128, 128)
        ' set page thumbnail
        page.Thumbnail = New Vintasoft.Imaging.Pdf.Tree.PdfImageResource(document, pageThumbnail, Vintasoft.Imaging.Pdf.PdfCompression.Jpeg)
    End Using

    ' save changes
    document.SaveChanges()

    ' close document
    document.Dispose()
End Sub

Remove embedded thumbnails of pages

An embedded thumbnail of page can be removed using PdfPage.RemoveThumbnail method. Embedded thumbnails of all pages can be removed using PdfPageCollection.RemoveThumbnails method.

Here is C#/VB.NET code that demonstrates how to save the embedded thumbnails of PDF pages to disk and remove embedded thumbnails from PDF document:

/// <summary>
/// Saves embedded thumnails of PDF document to files and
/// removes the embedded thumbnails from PDF document.
/// </summary>
/// <param name="pdfFilename">The filename of PDF document.</param>
public void SaveAndRemoveEmbeddedThumbnailsOfPdfDocument(string pdfFilename)
{
    // open PDF document in read-write mode
    Vintasoft.Imaging.Pdf.PdfDocument document = 
        new Vintasoft.Imaging.Pdf.PdfDocument(pdfFilename);

    // get the page collection
    Vintasoft.Imaging.Pdf.Tree.PdfPageCollection pages = document.Pages;

    bool hasEmbeddedThumbnails = false;

    // for each PDF page
    for (int i = 0; i < pages.Count; i++)
    {
        // if page has embedded thumbnail
        if (pages[i].Thumbnail != null)
        {
            // mark that PDF document has the embedded thumbnails for pages
            hasEmbeddedThumbnails = true;

            // get thumbnail as image
            using (Vintasoft.Imaging.VintasoftImage img = pages[i].Thumbnail.GetImage())
            {
                // save image to a file
                img.Save("page" + i.ToString() + "_thumb.png");
            }
        }
    }

    // if PDF document has the embedded thumbnails for pages
    if (hasEmbeddedThumbnails)
    {
        // remove embedded thumbnailsfrom PDF document
        document.Pages.RemoveThumbnails();

        // save changes
        document.SaveChanges();
    }

    // close document
    document.Dispose();
}

VB.NET

''' <summary>
''' Saves embedded thumnails of PDF document to files and
''' removes the embedded thumbnails from PDF document.
''' </summary>
''' <param name="pdfFilename">The filename of PDF document.</param>
Public Sub SaveAndRemoveEmbeddedThumbnailsOfPdfDocument(pdfFilename As String)
    ' open PDF document in read-write mode
    Dim document As New Vintasoft.Imaging.Pdf.PdfDocument(pdfFilename)

    ' get the page collection
    Dim pages As Vintasoft.Imaging.Pdf.Tree.PdfPageCollection = document.Pages

    Dim hasEmbeddedThumbnails As Boolean = False

    ' for each PDF page
    For i As Integer = 0 To pages.Count - 1
        ' if page has embedded thumbnail
        If pages(i).Thumbnail IsNot Nothing Then
            ' mark that PDF document has the embedded thumbnails for pages
            hasEmbeddedThumbnails = True

            ' get thumbnail as image
            Using img As Vintasoft.Imaging.VintasoftImage = pages(i).Thumbnail.GetImage()
                ' save image to a file
                img.Save("page" & i.ToString() & "_thumb.png")
            End Using
        End If
    Next

    ' if PDF document has the embedded thumbnails for pages
    If hasEmbeddedThumbnails Then
        ' remove embedded thumbnailsfrom PDF document
        document.Pages.RemoveThumbnails()

        ' save changes
        document.SaveChanges()
    End If

    ' close document
    document.Dispose()
End Sub

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