Find whether PDF contains images or text

Background

A PDF file can contain both text and images. Sometimes, a user might need to find out whether a PDF file contains only text, or it contains only images. We can also find whether it contain both or none.

Following code snippet shows you how to fulfill this requirement.

public static void CheckIfPdfContainsTextOrImages()
{
    // Instantiate a memoryStream object to hold the extracted text from Document
    MemoryStream ms = new MemoryStream();
    // Instantiate PdfExtractor object
    PdfExtractor extractor = new PdfExtractor();

    // Bind the input PDF document to extractor
    extractor.BindPdf(_dataDir + "FilledForm.pdf");
    // Extract text from the input PDF document
    extractor.ExtractText();
    // Save the extracted text to a text file
    extractor.GetText(ms);
    // Check if the MemoryStream length is greater than or equal to 1

    bool containsText = ms.Length >= 1;

    // Extract images from the input PDF document
    extractor.ExtractImage();

    // Calling HasNextImage method in while loop. When images will finish, loop will exit
    bool containsImage = extractor.HasNextImage();

    // Now find out whether this PDF is text only or image only

    if (containsText && !containsImage)
    {
        Console.WriteLine("PDF contains text only");
    }
    else if (!containsText && containsImage)
    {
        Console.WriteLine("PDF contains image only");
    }
    else if (containsText && containsImage)
    {
        Console.WriteLine("PDF contains both text and image");
    }
    else if (!containsText && !containsImage)
    {
        Console.WriteLine("PDF contains neither text or nor image");
    }
}