How do I embed a source PDF onto an existing page in a PDF?

I need to programmatically embed an existing PDF (a small graphic) onto a specfic page on an existing PDF. Using iTextSharp I've been able to add a new page containing this embedded PDF, but what need i开发者_Go百科s to modify an existing page by adding this graphic. Is this possible using iTextSharp or any other PDF-generation libarary?

I tend to do this sort of thing using Context, which is a Tex-based layout tool that in integrated into the pdftex Tex/Metapost engine. There's a learning curve involved, and installing Context isn't entirely trivial, but it makes very general programmatic document processing involving PDFs easy once you get the hang of it.

For this problem, you'd define two overlays, with the first overlay being the main PDF that you set to a background, and then on the page you want to change, defining a foreground overlay with a \setlayer command, which contains a single \framed box, which superimposes the second PDF using a \externalfigure command.

The nice thing about Context for this kind of task is that it works with PDF as its internal representation all the way through, so there is no unexpected blow up in file size or deterioration in image quality, which you can get with other tools that convert between formats.