Am I right in thinking that you have to use XML:FO in order to make PDF files out of xml files? If this is the case then can someone explain why you have to use this other technology instead of just using XSL.
For making HTML pages, I just use XSL, after all, it has been touted as the solution to all our presentation woes. But if this is the case, why then does pdf require this other technology, and what exactly does it do?
You don't
have to use XSL:FO. It's just easier compared to writing your own XML-to-PDF conversion tool (whether it's based on an XSL stylesheet or just
Java code parsing the XML). The reason why it's so difficult is the shear complexity of the PDF specification (e.g. font elements aren't that easy to play with).