How to highlights text in pdf document in c# using itextsharp.dll

Question

_{Monday, June 19, 2017 9:21 AM}

How to highlights text in pdf document in c# using itextsharp.dll for below scenario

1.pdf file is in byte[] format

2.pdf file is in folder

All replies (2)

_{Thursday, June 29, 2017 6:39 AM}

Hi Ganesan IT,

Thank you for posting here.

If you want to highlight text in pdf document using an existing PdfStamper called stamper, please see simple code.

PdfAnnotation highlight = PdfAnnotation.CreateMarkup(stamper.Writer, rect, null, PdfAnnotation.MARKUP_HIGHLIGHT, quad);

Once you have the highlight you can set the color using:

highlight.Color = BaseColor.YELLOW;

And then add it to your stamper

stamper.AddAnnotation(highlight,1);

Here is a sample:

using System;
using System.ComponentModel;
using System.Data;
using System.Text;
using System.Windows.Forms;
using System.IO;
using iTextSharp.text;
using iTextSharp.text.pdf;

namespace WindowsFormsApplication1
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            //Create a simple test file
            string outputFile = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.Desktop), "Test.pdf");

            using (FileStream fs = new FileStream(outputFile, FileMode.Create, FileAccess.Write, FileShare.None))
            {
                using (Document doc = new Document(PageSize.LETTER))
                {
                    using (PdfWriter w = PdfWriter.GetInstance(doc, fs))
                    {
                        doc.Open();
                        doc.Add(new Paragraph("This is a test"));
                        doc.Close();
                    }
                }
            }

            //Create a new file from our test file with highlighting
            string highLightFile = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.Desktop), "Highlighted.pdf");

            //Bind a reader and stamper to our test PDF
            PdfReader reader = new PdfReader(outputFile);

            using (FileStream fs = new FileStream(highLightFile, FileMode.Create, FileAccess.Write, FileShare.None))
            {
                using (PdfStamper stamper = new PdfStamper(reader, fs))
                {
                    //Create a rectangle for the highlight. NOTE: Technically this isn't used but it helps with the quadpoint calculation
                    iTextSharp.text.Rectangle rect = new iTextSharp.text.Rectangle(60.6755f, 749.172f, 94.0195f, 735.3f);
                    //Create an array of quad points based on that rectangle. NOTE: The order below doesn't appear to match the actual spec but is what Acrobat produces
                    float[] quad = { rect.Left, rect.Bottom, rect.Right, rect.Bottom, rect.Left, rect.Top, rect.Right, rect.Top };

                    //Create our hightlight
                    PdfAnnotation highlight = PdfAnnotation.CreateMarkup(stamper.Writer, rect, null, PdfAnnotation.MARKUP_HIGHLIGHT, quad);

                    //Set the color
                    highlight.Color = BaseColor.YELLOW;

                    //Add the annotation
                    stamper.AddAnnotation(highlight,1);
                }
            }

            this.Close();
        }
    }
}

Best Regards,

Hart

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_{Wednesday, July 5, 2017 2:00 AM}

I think Spire.PDF is a good alternative for your requirements. It supports to load a Pdf file from byte array as well as from a folder in disk. And it allows to highlight the selected text with custom color or to add markup annotation to specific range of text.

Highlight selected text

PdfTextFind[] results = pdf.Pages[0].FindText("Hello World").Finds;
foreach (PdfTextFind result in results)
{
    result.ApplyHighLight(Color.Green);
}

Markup text

//Load a sample PDF document
PdfDocument doc = new PdfDocument();
doc.LoadFromFile(@"C:\Users\Administrator\Desktop\sample.pdf");
PdfPageBase page = doc.Pages[0];

//Locate the text that you want to markup
PdfTextFind ptf =page.FindText("Highlight text").Finds[0];
//Create a Text Markup annotation
Font font = ptf.Font;
string markupText = "Higlight text";
PdfTextMarkupAnnotation annotation = new PdfTextMarkupAnnotation("Adminstrator", "Text Markup Annotation", markupText, ptf.Position, new PdfTrueTypeFont(font));
annotation.Border = new PdfAnnotationBorder(0.75f);
annotation.TextMarkupColor = Color.Yellow;   

//Add annotation to PDF page    
page.AnnotationsWidget.Add(annotation);
doc.SaveToFile("Annotation.pdf", FileFormat.PDF);