The cairo-pdf-outline-flags-t flags is used by the function cairo-pdf-surface-add-outline to specify the attributes of an outline item. These flags may be bitwise-or'd to produce any combination of flags.

(defcenum cairo-pdf-outline-flags-t
  (:open 1)
  (:bold 2)
  (:italic 4))  

:open

The outline item defaults to open in the PDF viewer.

:bold

The outline item is displayed by the viewer in bold text.

:italic

The outline item is displayed by the viewer in italic text.