PDF Objects

PDF files are made up of a series of objects. These objects can be in many different types, including dictionaries, streams, numbers, booleans, names, strings etc. For full details, see `The PDF Reference Manual'.

MuPDF represents all of these as a pdf_obj pointer. Such pointers are reference counted in the usual way:

$\begin{lstlisting} pdf_obj *pdf_keep_obj(fz_context *ctx, pdf_obj *obj); void pdf_drop_obj(fz_context *ctx, pdf_obj *obj); \end{lstlisting}$

Given such a pointer, the actual type of the object can be obtained using:

$\begin{lstlisting} int pdf_is_null(fz_context *ctx, pdf_obj *obj); int pdf_is_bo... ...df_obj *obj); int pdf_is_stream(fz_context *ctx, pdf_obj *obj); \end{lstlisting}$

These all return non-zero if the object is of the tested type, and zero otherwise.

To extract the data from a PDF object, you can use one of the following functions:

$\begin{lstlisting} /* safe, silent failure, no error reporting on type mismatche... ...f_obj *obj); int pdf_to_str_len(fz_context *ctx, pdf_obj *obj); \end{lstlisting}$

It is, in fact, safe to call any of these functions on any pdf_obj pointer. If the object is not of the expected type, a `safe' default will be returned.

Subsections

Arrays