Creates a check box with one widget on page, unchecked.
public PdfCheckBoxField AddCheckBox(string name, PdfPage page, PdfRectangle rectangle, PdfFieldOptions? options = null)
The field's fully qualified name, as for AddTextField(String, PdfPage, PdfRectangle, PdfFieldOptions?).
The page the widget is on, a page of this form's document.
The widget's rectangle, in default user space.
The field's flags, mark colour and size, widget colours and caption; null for the defaults.
ISO 32000-2 §12.7.5.2.3. A button field (FT Btn, no Radio or Pushbutton flag) merged with its widget, whose
appearance subdictionary has the on state Yes (a check mark in ZapfDingbats, or the Caption
character) and Off; AS is Off. Otherwise as AddTextField(String, PdfPage, PdfRectangle, PdfFieldOptions?) describes.