<?xml version="1.0" encoding="utf-8"?>
 <reference id="ref.fdf">
  <title>Forms Data Format functions</title>
  <titleabbrev>FDF</titleabbrev>

  <partintro>

   <simpara>
    Forms Data Format (FDF) is a format for handling
    forms within PDF documents. You should read the documentation at 
		  <ulink url="&spec.pdf.fdf;">&spec.pdf.fdf;</ulink>
    for more information on what FDF is and how it is used in general.
   </simpara>

   <note><simpara>
    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.
   </simpara></note>

   <simpara>
    The general idea of FDF is similar to HTML forms. The diffence 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
    (<function>fdf_create</function>) set the values of each input field
    (<function>fdf_set_value</function>) and associate it with a PDF form
    (<function>fdf_set_file</function>). Finally it has to be sent to the
    browser with MimeType <literal>application/vnd.fdf</literal>. The Acrobat
    reader plugin of your browser recognizes the MimeType,  reads the
    associated PDF form and fills in the data from the FDF document.
   </simpara>

   <simpara>
    If you look at an FDF-document with a text editor you will find a
    catalogue object with the name <literal>FDF</literal>. Such an object may
    contain a number of entries like <literal>Fields</literal>,
    <literal>F</literal>, <literal>Status</literal> etc..
    The most commonly used entries are <literal>Fields</literal> whicht points
    to a list of input fields, and <literal>F</literal> which contains the
    filename of the PDF-document this data belongs to. Those entries are
    referred to in the FDF documention as /F-Key or /Status-Key.
    Modifying this entries
    is done by functions like <function>fdf_set_file</function> and
    <function>fdf_set_status</function>. Fields are modified with
    <function>fdf_set_value</function>, <function>fdf_set_opt</function> etc..
   </simpara>
   <simpara>
    The following examples shows just the evaluation of form data.</simpara>
   <simpara></simpara>
    <example>
     <title>Evaluating a FDF document</title>
     <programlisting>
&lt;?php
// Save the FDF data into a temp file
$fdffp = fopen("test.fdf", "w");
fwrite($fdffp, $HTTP_FDF_DATA, strlen($HTTP_FDF_DATA));
fclose($fdffp);

// Open temp file and evaluate data
// The pdf form contained several input text fields with the names
// volume, date, comment, publisher, preparer, and two checkboxes
// show_publisher and show_preparer.
$fdf = fdf_open("test.fdf");
$volume = fdf_get_value($fdf, "volume");
echo "The volume field has the value '&lt;B>$volume&lt;/B>'&lt;BR>";

$date = fdf_get_value($fdf, "date");
echo "The date field has the value '&lt;B>$date&lt;/B>'&lt;BR>";

$comment = fdf_get_value($fdf, "comment");
echo "The comment field has the value '&lt;B>$comment&lt;/B>'&lt;BR>";

if(fdf_get_value($fdf, "show_publisher") == "On") {
  $publisher = fdf_get_value($fdf, "publisher");
  echo "The publisher field has the value '&lt;B>$publisher&lt;/B>'&lt;BR>";
} else
  echo "Publisher shall not be shown.&lt;BR>";

if(fdf_get_value($fdf, "show_preparer") == "On") {
  $preparer = fdf_get_value($fdf, "preparer");
  echo "The preparer field has the value '&lt;B>$preparer&lt;/B>'&lt;BR>";
} else
  echo "Preparer shall not be shown.&lt;BR>";
fdf_close($fdf);
?>
     </programlisting>
    </example>

  </partintro>

  <refentry id="function.fdf-open">
   <refnamediv>
    <refname>fdf_open</refname>
    <refpurpose>Open a FDF document</refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
     <methodsynopsis>
      <type>int</type><methodname>fdf_open</methodname>
      <methodparam><type>string</type><parameter>filename</parameter></methodparam>
     </methodsynopsis>
    <para>
     The <function>fdf_open</function> function opens
     a file with form data. This file must contain the data as returned
     from a PDF form. Currently, the file has to be created 'manually'
     by using <function>fopen</function> and writing the content
     of HTTP_FDF_DATA with <function>fwrite</function> into it.
     A mechanism like for HTML form data where for each input
     field a variable is created does not exist.</para>

    <para>
    <example>
     <title>Accessing the form data</title>
     <programlisting>
&lt;?php
// Save the FDF data into a temp file
$fdffp = fopen("test.fdf", "w");
fwrite($fdffp, $HTTP_FDF_DATA, strlen($HTTP_FDF_DATA));
fclose($fdffp);

// Open temp file and evaluate data
$fdf = fdf_open("test.fdf");
...
fdf_close($fdf);
?>
     </programlisting>
    </example></para>

    <para>
     See also <function>fdf_close</function>.</para>

   </refsect1>
  </refentry>

  <refentry id="function.fdf-close">
   <refnamediv>
    <refname>fdf_close</refname>
    <refpurpose>Close an FDF document</refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
     <methodsynopsis>
      <type>boolean</type><methodname>fdf_close</methodname>
      <methodparam><type>int</type><parameter>fdf_document</parameter></methodparam>
     </methodsynopsis>
    <para>
     The <function>fdf_close</function> function closes the FDF document.</para>

    <para>
     See also <function>fdf_open</function>.</para>

   </refsect1>
  </refentry>

  <refentry id="function.fdf-create">
   <refnamediv>
    <refname>fdf_create</refname>
    <refpurpose>Create a new FDF document</refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
     <methodsynopsis>
      <type>int</type><methodname>fdf_create</methodname>
      <methodparam><type>void</type><parameter/></methodparam>
     </methodsynopsis>
    <para>
     The <function>fdf_create</function> creates a new
     FDF document. This function is needed if one would like to
     populate input fields in a PDF document with data.</para>
    <para>
    <example>
     <title>Populating a PDF document</title>
     <programlisting>
&lt;?php
$outfdf = fdf_create();
fdf_set_value($outfdf, "volume", $volume, 0);

fdf_set_file($outfdf, "http:/testfdf/resultlabel.pdf");
fdf_save($outfdf, "outtest.fdf");
fdf_close($outfdf);
Header("Content-type: application/vnd.fdf");
$fp = fopen("outtest.fdf", "r");
fpassthru($fp);
unlink("outtest.fdf");
?>
     </programlisting>
    </example></para>

    <para>
     See also <function>fdf_close</function>,
              <function>fdf_save</function>,
              <function>fdf_open</function>.</para>

   </refsect1>
  </refentry>

  <refentry id="function.fdf-save">
   <refnamediv>
    <refname>fdf_save</refname>
    <refpurpose>Save a FDF document</refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
     <methodsynopsis>
      <type>int</type><methodname>fdf_save</methodname>
      <methodparam><type>string</type><parameter>filename</parameter></methodparam>
     </methodsynopsis>
    <para>
     The <function>fdf_save</function> function saves
     a FDF document.
     The FDF Toolkit provides a way to output the document to stdout if
     the parameter <parameter>filename</parameter>
     is '.'. This does not work if PHP is used as an apache module.
     In such a case one will have to write to a file and use e.g.
     <function>fpassthru</function>. to output it.</para>

    <para>
     See also <function>fdf_close</function> and example for
              <function>fdf_create</function>.</para>

   </refsect1>
  </refentry>

  <refentry id="function.fdf-get-value">
   <refnamediv>
    <refname>fdf_get_value</refname>
    <refpurpose>Get the value of a field</refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
     <methodsynopsis>
      <type>string</type><methodname>fdf_get_value</methodname>
      <methodparam><type>int</type><parameter>fdf_document</parameter></methodparam>
      <methodparam><type>string</type><parameter>fieldname</parameter></methodparam>
     </methodsynopsis>
    <para>
     The <function>fdf_get_value</function> function returns the
     value of a field.</para>

    <para>
     See also <function>fdf_set_value</function>.</para>

   </refsect1>
  </refentry>

  <refentry id="function.fdf-set-value">
   <refnamediv>
    <refname>fdf_set_value</refname>
    <refpurpose>Set the value of a field</refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
     <methodsynopsis>
      <type>boolean</type><methodname>fdf_set_value</methodname>
      <methodparam><type>int</type><parameter>fdf_document</parameter></methodparam>
      <methodparam><type>string</type><parameter>fieldname</parameter></methodparam>
      <methodparam><type>string</type><parameter>value</parameter></methodparam>
      <methodparam><type>int</type><parameter>isName</parameter></methodparam>
     </methodsynopsis>
    <para>
     The <function>fdf_set_value</function> function sets the
     value of a field. The last parameter determines if the field value
     is to be converted to a PDF Name (<parameter>isName</parameter> = 1)
     or set to a PDF String (<parameter>isName</parameter> = 0).</para>

    <para>
     See also <function>fdf_get_value</function>.</para>

   </refsect1>
  </refentry>

  <refentry id="function.fdf-next-field-name">
   <refnamediv>
    <refname>fdf_next_field_name</refname>
    <refpurpose>Get the next field name</refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
     <methodsynopsis>
      <type>string</type><methodname>fdf_next_field_name</methodname>
      <methodparam><type>int</type><parameter>fdf_document</parameter></methodparam>
      <methodparam><type>string</type><parameter>fieldname</parameter></methodparam>
     </methodsynopsis>
    <para>
     The <function>fdf_next_field_name</function> function returns the
     name of the field after the field in
     <parameter>fieldname</parameter> or the field name of the first field
     if the second paramter is &null;.</para>

    <para>
     See also <function>fdf_set_field</function>,
              <function>fdf_get_field</function>.</para>

   </refsect1>
  </refentry>

  <refentry id="function.fdf-set-ap">
   <refnamediv>
    <refname>fdf_set_ap</refname>
    <refpurpose>Set the appearance of a field</refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
     <methodsynopsis>
      <type>boolean</type><methodname>fdf_set_ap</methodname>
      <methodparam><type>int</type><parameter>fdf_document</parameter></methodparam>
      <methodparam><type>string</type><parameter>field_name</parameter></methodparam>
      <methodparam><type>int</type><parameter>face</parameter></methodparam>
      <methodparam><type>string</type><parameter>filename</parameter></methodparam>
      <methodparam><type>int</type><parameter>page_number</parameter></methodparam>
     </methodsynopsis>
    <para>
     The <function>fdf_set_ap</function> function sets the
     appearance of a field (i.e. the value of the /AP key).
     The possible values of <parameter>face</parameter>
     are 1=FDFNormalAP, 2=FDFRolloverAP, 3=FDFDownAP.</para>

   </refsect1>
  </refentry>

  <refentry id="function.fdf-set-status">
   <refnamediv>
    <refname>fdf_set_status</refname>
    <refpurpose>Set the value of the /STATUS key</refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
     <methodsynopsis>
      <type>boolean</type><methodname>fdf_set_status</methodname>
      <methodparam><type>int</type><parameter>fdf_document</parameter></methodparam>
      <methodparam><type>string</type><parameter>status</parameter></methodparam>
     </methodsynopsis>
    <para>
     The <function>fdf_set_status</function> sets the value
     of the /STATUS key.</para>

    <para>
     See also <function>fdf_get_status</function>.</para>

   </refsect1>
  </refentry>

  <refentry id="function.fdf-get-status">
   <refnamediv>
    <refname>fdf_get_status</refname>
    <refpurpose>Get the value of the /STATUS key</refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
     <methodsynopsis>
      <type>string</type><methodname>fdf_get_status</methodname>
      <methodparam><type>int</type><parameter>fdf_document</parameter></methodparam>
     </methodsynopsis>
    <para>
     The <function>fdf_get_status</function> returns the value
     of the /STATUS key.</para>

    <para>
     See also <function>fdf_set_status</function>.</para>

   </refsect1>
  </refentry>

  <refentry id="function.fdf-set-file">
   <refnamediv>
    <refname>fdf_set_file</refname>
    <refpurpose>Set the value of the /F key</refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
     <methodsynopsis>
      <type>boolean</type><methodname>fdf_set_file</methodname>
      <methodparam><type>int</type><parameter>fdf_document</parameter></methodparam>
      <methodparam><type>string</type><parameter>filename</parameter></methodparam>
     </methodsynopsis>
    <para>
     The <function>fdf_set_file</function> sets the value
     of the /F key. The /F key is just a reference to a PDF form
     which is to be populated with data.
     In a web environment it is a URL (e.g. http:/testfdf/resultlabel.pdf).</para>

    <para>
     See also <function>fdf_get_file</function> and example for
              <function>fdf_create</function>.</para>

   </refsect1>
  </refentry>

  <refentry id="function.fdf-get-file">
   <refnamediv>
    <refname>fdf_get_file</refname>
    <refpurpose>Get the value of the /F key</refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
     <methodsynopsis>
      <type>string</type><methodname>fdf_get_file</methodname>
      <methodparam><type>int</type><parameter>fdf_document</parameter></methodparam>
     </methodsynopsis>
    <para>
     The <function>fdf_set_file</function> returns the value
     of the /F key.</para>

    <para>
     See also <function>fdf_set_file</function>.</para>

   </refsect1>
  </refentry>

  <refentry id="function.fdf-set-flags">
   <refnamediv>
    <refname>fdf_set_flags</refname>
    <refpurpose>Sets a flag of a field</refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
     <methodsynopsis>
      <type>boolean</type><methodname>fdf_set_flags</methodname>
      <methodparam><type>int</type><parameter>fdf_document</parameter></methodparam>
      <methodparam><type>string</type><parameter>fieldname</parameter></methodparam>
      <methodparam><type>int</type><parameter>whichFlags</parameter></methodparam>
      <methodparam><type>int</type><parameter>newFlags</parameter></methodparam>
     </methodsynopsis>
    <para>
     The <function>fdf_set_flags</function> sets certain flags
     of the given field <parameter>fieldname</parameter>.
    </para>
    <para>
     See also <function>fdf_set_opt</function>.
    </para>
   </refsect1>
  </refentry>

  <refentry id="function.fdf-set-opt">
   <refnamediv>
    <refname>fdf_set_opt</refname>
    <refpurpose>Sets an option of a field</refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
     <methodsynopsis>
      <type>boolean</type><methodname>fdf_set_opt</methodname>
      <methodparam><type>int</type><parameter>fdf_document</parameter></methodparam>
      <methodparam><type>string</type><parameter>fieldname</parameter></methodparam>
      <methodparam><type>int</type><parameter>element</parameter></methodparam>
      <methodparam><type>string</type><parameter>str1</parameter></methodparam>
      <methodparam><type>string</type><parameter>str2</parameter></methodparam>
     </methodsynopsis>
    <para>
     The <function>fdf_set_opt</function> sets options 
     of the given field <parameter>fieldname</parameter>.
    </para>
    <para>
     See also <function>fdf_set_flags</function>.
    </para>
   </refsect1>
  </refentry>

  <refentry id="function.fdf-set-submit-form-action">
   <refnamediv>
    <refname>fdf_set_submit_form_action</refname>
    <refpurpose>Sets an javascript action of a field</refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
     <methodsynopsis>
      <type>boolean</type><methodname>fdf_set_submit_form_action</methodname>
      <methodparam><type>int</type><parameter>fdf_document</parameter></methodparam>
      <methodparam><type>string</type><parameter>fieldname</parameter></methodparam>
      <methodparam><type>int</type><parameter>trigger</parameter></methodparam>
      <methodparam><type>string</type><parameter>script</parameter></methodparam>
      <methodparam><type>int</type><parameter>flags</parameter></methodparam>
     </methodsynopsis>
    <para>
     The <function>fdf_set_submit_form_action</function> sets a submit form
     action for the given field <parameter>fieldname</parameter>.
    </para>
    <para>
     See also <function>fdf_set_javascript_action</function>.
    </para>
   </refsect1>
  </refentry>

  <refentry id="function.fdf-set-javascript-action">
   <refnamediv>
    <refname>fdf_set_javascript_action</refname>
    <refpurpose>Sets an javascript action of a field</refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
     <methodsynopsis>
      <type>boolean</type><methodname>fdf_set_javascript_action</methodname>
      <methodparam><type>int</type><parameter>fdf_document</parameter></methodparam>
      <methodparam><type>string</type><parameter>fieldname</parameter></methodparam>
      <methodparam><type>int</type><parameter>trigger</parameter></methodparam>
      <methodparam><type>string</type><parameter>script</parameter></methodparam>
     </methodsynopsis>
    <para>
     The <function>fdf_set_javascript_action</function> sets a javascript
     action for the given field <parameter>fieldname</parameter>.
    </para>
    <para>
     See also <function>fdf_set_submit_form_action</function>.
    </para>
   </refsect1>
  </refentry>
 </reference>

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