How to Make a PDF Searchable in C# and VB.NET using PDF Extractor SDK

The sample source codes below show how to make a PDF document searchable in C# and VB.NET using ByteScout PDF Extractor SDK.

It is also possible to make an unsearchable PDF.

How to Make Searchable PDF in C#

using Bytescout.PDFExtractor;

// To make OCR work you should add to your project references to Bytescout.PDFExtractor.dll and Bytescout.PDFExtractor.OCRExtension.dll 

namespace MakeSearchablePDF
{
    class Program
    {
        static void Main(string[] args)
        {
            // Create Bytescout.PDFExtractor.TextExtractor instance
            SearchablePDFMaker searchablePDFMaker = new SearchablePDFMaker();
            searchablePDFMaker.RegistrationName = "demo";
            searchablePDFMaker.RegistrationKey = "demo";

            // Load sample PDF document
            searchablePDFMaker.LoadDocumentFromFile("sample_ocr.pdf");
            
            // Set the location of "tessdata" folder containing language data files
            searchablePDFMaker.OCRLanguageDataFolder = @"c:\Program Files\Bytescout PDF Extractor SDK\Redistributable\net2.00\tessdata\";

            // Set OCR language
            searchablePDFMaker.OCRLanguage = "eng"; // "eng" for english, "deu" for German, "fra" for French, "spa" for Spanish etc - according to files in /tessdata

            // Set PDF document rendering resolution
            searchablePDFMaker.OCRResolution = 300;

            // Save extracted text to file
            searchablePDFMaker.MakePDFSearchable("output.pdf");

            // Open output file in default associated application
            System.Diagnostics.Process.Start("output.pdf");
        }
    }
}

How to Make Searchable PDF in Visual Basic .NET

Imports Bytescout.PDFExtractor

Module Module1

    Sub Main()

        ' Create Bytescout.PDFExtractor.TextExtractor instance
        Dim searchablePdfMaker As SearchablePDFMaker = New SearchablePDFMaker()
        searchablePdfMaker.RegistrationName = "demo"
        searchablePdfMaker.RegistrationKey = "demo"

        ' Load sample PDF document
        searchablePdfMaker.LoadDocumentFromFile("sample_ocr.pdf")

        ' Set the location of "tessdata" folder containing language data files
        searchablePdfMaker.OCRLanguageDataFolder = "c:\Program Files\Bytescout PDF Extractor SDK\Redistributable\net2.00\tessdata\"

        ' Set OCR language
        searchablePdfMaker.OCRLanguage = "eng" ' "eng" for english, "deu" for German, "fra" for French, "spa" for Spanish etc - according to files in /tessdata

        ' Set PDF document rendering resolution
        searchablePdfMaker.OCRResolution = 300

        ' Save extracted text to file
        searchablePdfMaker.MakePDFSearchable("output.pdf")

        '/ Open output file in default associated application
        System.Diagnostics.Process.Start("output.pdf")

    End Sub

End Module