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                                                         694
          CHAPTER 8                                                                  Interactive Features



BIT POSITION      NAME                      MEANING

20                Sort                      If set, the field’s option items should be sorted alphabetically. This flag
                                            is intended for use by form authoring tools, not by PDF viewer appli-
                                            cations. Viewers should simply display the options in the order in
                                            which they occur in the Opt array (see Table 8.80).

22                MultiSelect               (PDF 1.4) If set, more than one of the field’s option items may be se-
                                            lected simultaneously; if clear, no more than one item at a time may
                                            be selected.

23                DoNotSpellCheck           (PDF 1.4) If set, text entered in the field is not spell-checked. This flag
                                            is meaningful only if the Combo and Edit flags are both set.

27                CommitOnSelChange         (PDF 1.5) If set, the new value is committed as soon as a selection is
                                            made with the pointing device. This option enables applications to
                                            perform an action once a selection is made, without requiring the user
                                            to exit the field. If clear, the new value is not committed until the user
                                            exits the field.

          The various types of choice fields are distinguished by flags in the Ff entry, as
          shown in Table 8.79. Table 8.80 shows the field dictionary entries specific to
          choice fields.

                             TABLE 8.80 Additional entries specific to a choice field
KEY       TYPE           VALUE

Opt       array          (Optional) An array of options to be presented to the user. Each element of the array is
                         either a text string representing one of the available options or an array consisting of two
                         text strings: the option’s export value and the text to be displayed as the name of the op-
                         tion (see implementation note 122 in Appendix H).
                         If this entry is not present, no choices should be presented to the user.

TI        integer        (Optional) For scrollable list boxes, the top index (the index in the Opt array of the first
                         option visible in the list). Default value: 0.

I         array          (Sometimes required, otherwise optional; PDF 1.4) For choice fields that allow multiple
                         selection (MultiSelect flag set), an array of integers, sorted in ascending order, represent-
                         ing the zero-based indices in the Opt array of the currently selected option items. This
                         entry is required when two or more elements in the Opt array have different names but
                         the same export value or when the value of the choice field is an array. In other cases, the
                         entry is permitted but not required. If the items identified by this entry differ from those
                         in the V entry of the field dictionary (see below), the V entry takes precedence.

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