Forms Data Format (FDF) is a format for handling
forms within PDF documents. You should read the
documentation at
http://partners.adobe.com/asn/developer/acrosdk/forms.html
for more information on what FDF is and how it is used
in general.
The general idea of FDF is similar to HTML forms.
The difference is basically the format how data is
transmitted to the server when the submit button is
pressed (this is actually the Form Data Format) and the
format of the form itself (which is the Portable
Document Format, PDF). Processing the FDF data is one
of the features provided by the fdf functions. But
there is more. One may as well take an existing PDF
form and populated the input fields with data without
modifying the form itself. In such a case one would
create a FDF document (fdf_create()) set the values of each
input field (fdf_set_value()) and associate
it with a PDF form (fdf_set_file()). Finally it has to
be sent to the browser with MimeType application/vnd.fdf. The Acrobat reader
plugin of your browser recognizes the MimeType, reads
the associated PDF form and fills in the data from the
FDF document.
If you look at an FDF-document with a text editor
you will find a catalogue object with the name FDF. Such an object may contain a
number of entries like Fields,
F,
Status etc.. The most commonly used entries are
Fields which points to a list
of input fields, and F which
contains the filename of the PDF-document this data
belongs to. Those entries are referred to in the FDF
documentation as /F-Key or /Status-Key. Modifying this
entries is done by functions like
fdf_set_file() and
fdf_set_status(). Fields are modified with
fdf_set_value(),
fdf_set_opt() etc..
You need the FDF toolkit SDK available from
http://partners.adobe.com/asn/developer/acrosdk/forms.html.
As of PHP 4.3 you need at least SDK version 5.0. The
FDF toolkit library is available in binary form only,
platforms supported by Adobe are Win32, Linux, Solaris
and AIX.
You must compile PHP with
--with-fdftk[=DIR].
注: If you run into problems configuring PHP with fdftk support, check whether the header file fdftk.h and the library libfdftk.so are at the right place. The configure script supports both the directory structure of the FDF SDK distribution and the usual DIR/include / DIR/lib layout, so you can point it either directly to the unpacked distribution directory or put the header file and the appropriate library for your platform into e.g. /usr/local/include and /usr/local/lib and configure with --with-fdftk=/usr/local.
Note to Win32 Users: In order to enable this module on a Windows environment, you must copy fdftk.dll from the DLL folder of the PHP/Win32 binary package to the SYSTEM32 folder of your windows machine. (Ex: C:\WINNT\SYSTEM32 or C:\WINDOWS\SYSTEM32)
Most fdf functions require a fdf resource as their first
parameter. A fdf
resource is a handle to an opened fdf file. fdf resources may be
obtained using fdf_create(),
fdf_open() and
fdf_open_string().
以下的常數由此延伸定義, 只在這個延伸被編譯成PHP或實行時期被動態載入時有效。
The following examples shows just the evaluation
of form data.