How to debug a corrupt pdf file?

Question

Hi, im generating pdf files using a ruby library called "prawn". I have one particular file that seems to be considered "Corrupt" by adobe reader. It shows up fine in both preview and in adobe reader. It gives errors like:

Sometimes I get: "Could not find the XObject named '%s'.

Othertimes I get: "Could not find the XObject named "Im4".

Then always I get: "An error exists on this page. Acrobat may not display the page correctly. Please contact the person who created the PDF document to correct the problem."

Is there a way to open a pdf with some tool and have it tell you what is technically wrong with the pdf? Im sure I could figure it out quickly with something like this...

thanks Joel

Answer 1

A PDF is a dump of PDF objects so it sounds like objects are missing or the references pointing to the object are wrong. You can view a PDF in a text editor and see the refs table and you can see the PDF objects in Acrobat (I wrote a blog article on this at (http://pdf.jpedal.org/java-pdf-blog/bid/10479/Viewing-PDF-objects).

Your best bet might to take an Open Source tool like IText which can read PDFs and add some debugging code to get it to show the object structures.