2.3. Creating PDF

PDF files may be produced either directly by application programs or indirectly by conversion from other file formats or imaging models. As PDF documents and applications that process them become more prevalent, new ways of creating and using PDF will be invented. One of the goals of this book is to make the file format accessible so that application developers can expand on the ideas behind PDF and the applications that initially support it.

Many applications can generate PDF files directly, and some can import them as well. This direct approach is preferable, since it gives the application access to the full capabilities of PDF, including the imaging model and the interactive and document interchange features. Alternatively, applications that do not generate PDF directly can produce PDF output indirectly. There are two principal indirect methods: