// CHAPTER 16. Optional Content Groups

/** Begins retrieving optional content group names. The serial number 0..n - 1
is returned. */
function startGetOCGList(pdf)

/** Retrieves an OCG name, given its serial number 0..n - 1. */
function ocgListEntry(n)

/** Ends retrieval of optional content group names. */
function endGetOCGList()

/** Renames an optional content group. */
function ocgRename(pdf, name_from, name_to)

/** Ensures that every optional content group appears in the OCG order list. */
function ocgOrderAll(pdf)

/** Coalesces optional content groups. For example, if we merge or stamp two
files both with an OCG called "Layer 1", we will have two different optional
content groups. This function will merge the two into a single optional
content group. */
function ocgCoalesce(pdf)