Martin,

>I guess the main issue about this is that to be able to generate PDF you have to pay royalties to Adobe. I understand this is why there are no 100% free PDF tools. There are some free of charge, but which show you ads in turn. You have to have some business model to support the cost.

As Rich said, there are no royalties due to Adobe for you to create your own PDF file... UNLESS you license their library (mega-bucks) to make the job easier. There are also some 3rd-party libraries that can be licensed for more reasonable amounts (hundreds of dollars) and at least one I have seen for under $100.

However, you can crack open a PDF and study the structure and refer to the free docs from Adobe to figure it out. It's just a bunch of collections that are cross-referenced, with an index at the end that points to specific locations in the file for key elements. Then you can spend a few hundred or thousand hours writing your own PDF creator. OK, that's exaggerating a bit. You can create a library to make simple PDFs with simple-layout text only in just a few hours.

I studied the structure when working on an annotation project and know what needs to be done... just haven't found the time yet to pull it together and post it.