How to edit PDF files using Incremental Updates

Yesterday, Mark wrote about how wrong references tables can be. He’s also previously written about how to edit PDF files by adding a second reference table, and Daniel made a whole series on making your own PDF file. I thought it might be fun to put the theory into practise and edit Daniel’s Hello World PDF by…

Read More

Why XFA support is important?

One of the big enhancements we are adding into our Version 5 release of our PDF library is support for XFA, so I thought it would be very helpful to tell you what XFA is and why it matters. XFA is an area of the PDF specification which is very poorly supported. I can only…

Read More

Why we need to see your PDF files…

What makes writing a PDF parser especially interesting (ie complex) is that the specification is often ambiguous and that PDF is a very complex structure. To Display a PDF file requires the parser to correctly scan the PDF object data structure, to correctly decode and assemble all the data, and then parse the stream of…

Read More

Why can’t I just open and edit a PDF file

People sometimes try to edit a PDF file by opening the file in a text editor. This very rarely works for 3 reasons. Firstly, a PDF file is effectively a dump of PDF objects. The file contains a reference table giving the exact byte offset locations of each object from the start of the file,…

Read More