Extract image from PDF using itextsharp

Question

I am trying to extract all the images from a pdf using itextsharp but can\'t seem to overcome this one hurdle.

The error occures on the line System.Drawing.I

Answer 1

Works for me like this, using these two methods:

    public static List ExtractImagesFromPDF(byte[] bytes)
    {
        var imgs = new List();
        var pdf = new PdfReader(bytes);

        try
        {
            for (int pageNumber = 1; pageNumber <= pdf.NumberOfPages; pageNumber++)
            {
                PdfDictionary pg = pdf.GetPageN(pageNumber);
                List objs = FindImageInPDFDictionary(pg);

                foreach (var obj in objs)
                {
                    if (obj != null)
                    {
                        int XrefIndex = Convert.ToInt32(((PRIndirectReference)obj).Number.ToString(System.Globalization.CultureInfo.InvariantCulture));
                        PdfObject pdfObj = pdf.GetPdfObject(XrefIndex);
                        PdfStream pdfStrem = (PdfStream)pdfObj;
                        var pdfImage = new PdfImageObject((PRStream)pdfStrem);
                        var img = pdfImage.GetDrawingImage();

                        imgs.Add(img);
                    }
                }
            }
        }
        finally
        {
            pdf.Close();
        }

        return imgs;
    }

    private static List FindImageInPDFDictionary(PdfDictionary pg)
    {
        var res = (PdfDictionary)PdfReader.GetPdfObject(pg.Get(PdfName.RESOURCES));
        var xobj = (PdfDictionary)PdfReader.GetPdfObject(res.Get(PdfName.XOBJECT));
        var pdfObgs = new List();

        if (xobj != null)
        {
            foreach (PdfName name in xobj.Keys)
            {
                PdfObject obj = xobj.Get(name);
                if (obj.IsIndirect())
                {
                    var tg = (PdfDictionary)PdfReader.GetPdfObject(obj);
                    var type = (PdfName)PdfReader.GetPdfObject(tg.Get(PdfName.SUBTYPE));

                    if (PdfName.IMAGE.Equals(type)) // image at the root of the pdf
                    {
                        pdfObgs.Add(obj);
                    }
                    else if (PdfName.FORM.Equals(type)) // image inside a form
                    {
                        FindImageInPDFDictionary(tg).ForEach(o => pdfObgs.Add(o));
                    }
                    else if (PdfName.GROUP.Equals(type)) // image inside a group
                    {
                        FindImageInPDFDictionary(tg).ForEach(o => pdfObgs.Add(o));
                    }
                }
            }
        }

        return pdfObgs;
    }