How to Create the Automatic Bookmarking in PDF

The Syncfusion Essential® PDF is a feature-rich and high performance .NET PDF library used to create, read, and edit PDF documents programmatically without Adobe dependencies. Using this library, you can create the automatic Bookmarking in PDF document using C#.

In this article, we have created a bookmark based on the font size which is used in the PDF document by extracting its text and font size.

Steps to create the automatic Bookmarking in PDF document programmatically:

1. Create a new console application project.
2. Install the Syncfusion.Pdf.Net.Core NuGet package as a reference to your console application from Nuget.org.
   
3. Include the following namespaces in the Program.cs file.

C#

using Syncfusion.Drawing;
using Syncfusion.Pdf;
using Syncfusion.Pdf.Interactive;
using Syncfusion.Pdf.Parsing;

4. Use the following code sample in Program.cs to create an automatic bookmark.

C#

// Open the PDF file using a file stream.
FileStream pdfFilePath = new FileStream(@"..\..\..\Data\Sample.pdf", FileMode.Open, FileAccess.Read);

// Using statement ensures proper disposal of resources after use.
using (PdfLoadedDocument loadedDocument = new PdfLoadedDocument(pdfFilePath))
{
   // Iterate through each page in the loaded PDF document.
   for (int i = 0; i < loadedDocument.Pages.Count; i++)
   {
       // Get the current page.
       PdfPageBase page = loadedDocument.Pages[i];

       // Initialize a collection to store text lines extracted from the page.
       var lineCollection = new TextLineCollection();

       // Extract text from the page and get a collection of text lines.
       string extractedText = page.ExtractText(out lineCollection);

       // Initialize a variable to store the current bookmark.
       PdfBookmark bookmark = null;
       //Iterate the text line collection to create bookmarks.
       foreach (TextLine line in lineCollection.TextLine)
       {
           if (line.Text != null && line.Text != " ")
           {
               float fontSize = GetFontSize(line);
               if (fontSize > 15)
               {
                   // Create a bookmark for header 1.
                   string header1 = line.Text;
                   bookmark = loadedDocument.Bookmarks.Add(header1);
                   bookmark.Destination = new PdfDestination(page);
                   bookmark.Destination.Location = new PointF(line.Bounds.X, line.Bounds.Y);
                   bookmark.TextStyle = PdfTextStyle.Bold;
               }
               else if (fontSize >= 12 && fontSize <= 15 && bookmark != null)
               {
                   // Create a bookmark for header 2.
                   string header2 = line.Text;
                   PdfBookmark childBookmark = bookmark.Add(header2);
                   childBookmark.Destination = new PdfDestination(page);
                   childBookmark.Destination.Location = new PointF(line.Bounds.X, line.Bounds.Y);
                   childBookmark.TextStyle = PdfTextStyle.Bold;

               }
           }
       }
   }

   // Create a memory stream to save the modified PDF document.
   MemoryStream ms = new MemoryStream();

   // Save the modified PDF document to the memory stream.
   loadedDocument.Save(ms);

   // Write the contents of the memory stream to a file named "output.pdf".
   File.WriteAllBytes("output.pdf", ms.ToArray());

   // Close the loaded document.
   loadedDocument.Close(true);
}


static float GetFontSize(TextLine textLine)
{
   // Get a collection of words in the current line.
   List<TextWord> textWordCollection = textLine.WordCollection;
   float fontSize = 0;
   //Iterate through each word in the current line.
   foreach (var word in textWordCollection)
   {
       //Iterate through each glyph in the word.
       foreach (var glyph in word.Glyphs)
       {
           //Get the font size of the glyph.
           if (glyph.FontSize > 0)
           {
               fontSize = glyph.FontSize;
               break;
           }
       }
       if (fontSize != 0)
           break;
   }
   return fontSize;
}

A complete working sample can be downloaded from create_the_automatic_Bookmarking.zip

By executing the program, you will get the PDF document as follows.

Take a moment to peruse the documentation, where you can find other options like adding, Inserting, removing, and modifying bookmarks in an existing PDF document and features like named destination, interactive annotations, and insert hyperlink to PDF with code examples.

Refer here to explore the rich set of Syncfusion Essential® PDF features.