Generates a normal appearance for each widget: an on and an Off appearance stream, the on one showing the widget's caption
(MK CA) in ZapfDingbats; each widget's appearance state is set to match the value.
public void GenerateAppearances()
ISO 32000-2 §12.7.5.2.3, §12.7.5.2.4 and §12.5.6.19 (Table 192: CA, BG, BC, R). Each widget's
AP becomes a normal appearance subdictionary with the on state and Off, two new form XObjects (down and rollover
appearances are dropped). Both draw the MK background and border in the widget's border style; the on appearance then
shows the caption's character codes in ZapfDingbats (§9.6.2.2, Annex D.6), centred, in the default appearance's size (an auto
size fits the widget) and colour. Without a caption a check box shows a check mark (4) and a radio button a dot
(l). The default appearance font is used when it is ZapfDingbats; otherwise a ZapfDingbats font is added to the
appearance's resources.
The on state keeps its name; a widget without one gets Yes (check box) or its position in Kids (radio button,
Table 230). Nothing changes when building an appearance fails.