FormField is the abstract class that is being extended by all fields such as CheckBoxField, ChoiceField, ComboField,
PushButtonField, RadioButtonGroupField, SignatureField and TextField.FreeHighlightAnnotSettings.ShapeDrawingTool.initAnnot(PointF), instantiates a FreeText Annotation using the values from FreeTextAnnotSettings;
adjusts the Annotations's bounds as the user drags; and calls FreeTextDrawingTool.finishDrawing() when the user releases.