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.Image ImgPDF = System.Drawing.Image.FromStream(MS);
giving an error of "Parameter is not valid".
I think it works when the image is a bitmap but not of any other format.
I have this following code - sorry for the length;
private void Form1_Load(object sender, EventArgs e)
{
FileStream fs = File.OpenRead(@"reader.pdf");
byte[] data = new byte[fs.Length];
fs.Read(data, 0, (int)fs.Length);
List<System.Drawing.Image> ImgList = new List<System.Drawing.Image>();
iTextSharp.text.pdf.RandomAccessFileOrArray RAFObj = null;
iTextSharp.text.pdf.PdfReader PDFReaderObj = null;
iTextSharp.text.pdf.PdfObject PDFObj = null;
iTextSharp.text.pdf.PdfStream PDFStremObj = null;
try
{
RAFObj = new iTextSharp.text.pdf.RandomAccessFileOrArray(data);
PDFReaderObj = new iTextSharp.text.pdf.PdfReader(RAFObj, null);
for (int i = 0; i <= PDFReaderObj.XrefSize - 1; i++)
{
PDFObj = PDFReaderObj.GetPdfObject(i);
if ((PDFObj != null) && PDFObj.IsStream())
{
PDFStremObj = (iTextSharp.text.pdf.PdfStream)PDFObj;
iTextSharp.text.pdf.PdfObject subtype = PDFStremObj.Get(iTextSharp.text.pdf.PdfName.SUBTYPE);
if ((subtype != null) && subtype.ToString() == iTextSharp.text.pdf.PdfName.IMAGE.ToString())
{
byte[] bytes = iTextSharp.text.pdf.PdfReader.GetStreamBytesRaw((iTextSharp.text.pdf.PRStream)PDFStremObj);
if ((bytes != null))
{
try
{
System.IO.MemoryStream MS = new System.IO.MemoryStream(bytes);
MS.Position = 0;
System.Drawing.Image ImgPDF = System.Drawing.Image.FromStream(MS);
ImgList.Add(ImgPDF);
}
catch (Exception)
{
}
}
}
}
}
PDFReaderObj.Close();
}
catch (Exception ex)
{
throw new Exception(ex.Message);
}
} //Form1_Load
Works for me like this, using these two methods:
public static List<System.Drawing.Image> ExtractImagesFromPDF(byte[] bytes)
{
var imgs = new List<System.Drawing.Image>();
var pdf = new PdfReader(bytes);
try
{
for (int pageNumber = 1; pageNumber <= pdf.NumberOfPages; pageNumber++)
{
PdfDictionary pg = pdf.GetPageN(pageNumber);
List<PdfObject> 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<PdfObject> 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<PdfObject>();
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;
}
In newer version of iTextSharp, the 1st parameter of ImageRenderInfo.CreateForXObject
is not Matrix
anymore but GraphicsState
. @der_chirurg's approach should work. I tested myself with the information from the following link and it worked beautifully:
http://www.thevalvepage.com/swmonkey/2014/11/26/extract-images-from-pdf-files-using-itextsharp/
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