XVII. Forms Data Format functions
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.
Note:
Currently Adobe only provides a libc5 compatible version for Linux. Tests
with glibc2 resulted in a segmentation fault. If somebody is able to
make it work, please comment on this page.
Note:
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. They should be in fdftk-dir/include and
fdftk-dir/lib. This will not be the case if you just unpack
the FdfTk distribution.
The general idea of FDF is similar to HTML forms. The diffence is
basically the format how filled in 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.
The following examples shows just the evaluation of form data.
Example 1. Evaluating a FDF document 1
2 <?php
3 // Save the FDF data into a temp file
4 $fdffp = fopen("test.fdf", "w");
5 fwrite($fdffp, $HTTP_FDF_DATA, strlen($HTTP_FDF_DATA));
6 fclose($fdffp);
7
8 // Open temp file and evaluate data
9 // The pdf form contained several input text fields with the names
10 // volume, date, comment, publisher, preparer, and two checkboxes
11 // show_publisher and show_preparer.
12 $fdf = fdf_open("test.fdf");
13 $volume = fdf_get_value($fdf, "volume");
14 echo "The volume field has the value '<B>$volume</B>'<BR>";
15
16 $date = fdf_get_value($fdf, "date");
17 echo "The date field has the value '<B>$date</B>'<BR>";
18
19 $comment = fdf_get_value($fdf, "comment");
20 echo "The comment field has the value '<B>$comment</B>'<BR>";
21
22 if(fdf_get_value($fdf, "show_publisher") == "On") {
23 $publisher = fdf_get_value($fdf, "publisher");
24 echo "The publisher field has the value '<B>$publisher</B>'<BR>";
25 } else
26 echo "Publisher shall not be shown.<BR>";
27
28 if(fdf_get_value($fdf, "show_preparer") == "On") {
29 $preparer = fdf_get_value($fdf, "preparer");
30 echo "The preparer field has the value '<B>$preparer</B>'<BR>";
31 } else
32 echo "Preparer shall not be shown.<BR>";
33 fdf_close($fdf);
34 ?>
35 |
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