PDFsharp & MigraDoc Foundation

I create a 1 page PDF that contains a full page JPG image. I can open and view that PDF file with Adobe. Problem is, I cannot extract the image out of the PDF using PdfSharp.

The problem is that in the InitializeJpeg method in PdfImage, a PdfArray object is created holding two PdfName objects. PdfName("/FlateDecode") and PdfName("/DCTDecode").

In the sample code for reading an image from a PDF, the following code does not work when the /Filter key contains a PdfArray value:
filter = image.Elements.GetName("/Filter");

switch (filter)
{
case "/DCTDecode":
ExportJpegImage(image, ref count, InImagePath);
break;

case "/FlateDecode":
ExportAsPngImage(image, ref count, InImagePath );
break;
}

I made a code change to InitializeJpeg that fixes the problem for me. The following code is always run. No matter the length of imageDataCompressed:
Stream = new PdfStream(imageBits, this);
Elements[Keys.Length] = new PdfInteger(streamLength);
Elements[Keys.Filter] = new PdfName("/DCTDecode");

Only, I don't understand why I can't write as "/FlateDecode". The Adobe PDF reader rejects the PDF file created this way.

Thanks,

The Export Images sample is not prepared for images that are compressed twice.
In your case you must call the FlateDecoder to get a JPEG file.

_________________
Regards
Thomas Hoevel
PDFsharp Team