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CHAPTER 8 Interactive Features
The field’s text is held in a text string (or, beginning with PDF 1.5, a stream) in the
V (value) entry of the field dictionary. The contents of this text string or stream
are used to construct an appearance stream for displaying the field, as described
under “Variable Text” on page 677. The text is presented in a single style (font,
size, color, and so forth), as specified by the DA (default appearance) string.
If the FileSelect flag (PDF 1.4) is set, the field functions as a file-select control. In
this case, the field’s text represents the pathname of a file whose contents are to be
submitted as the field’s value:
• For fields submitted in HTML Form format, the submission uses the MIME
content type multipart / form-data, as described in Internet RFC 2045, Multi-
purpose Internet Mail Extensions (MIME), Part One: Format of Internet Message
Bodies (see the Bibliography).
• For Forms Data Format (FDF) submission, the value of the V entry in the FDF
field dictionary (see “FDF Fields” on page 717) is a file specification (Section
3.10, “File Specifications”) identifying the selected file.
• XML format is not supported for file-select controls; therefore, no value is sub-
mitted in this case.
Besides the usual entries common to all fields (see Table 8.69 on page 675) and to
fields containing variable text (see Table 8.71), the field dictionary for a text field
can contain the additional entry shown in Table 8.78.
TABLE 8.78 Additional entry specific to a text field
KEY TYPE VALUE
MaxLen integer (Optional; inheritable) The maximum length of the field’s text, in characters.
Example 8.18 shows the object definitions for a typical text field.
Example 8.18
6 0 obj
<< /FT /Tx
/Ff … % Set Multiline flag
/T ( Silly prose )
/DA ( 0 0 1 rg /Ti 12 Tf )
/V ( The quick brown fox ate the lazy mouse )
/AP << /N 5 0 R >>
>>
endobj
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