Chapter 16
Optional Content Groups

cpdf -ocg-list in.pdf

cpdf -ocg-rename -ocg-rename-from <a> -ocg-rename-to <b> in.pdf -o out.pdf

cpdf -ocg-order-all in.pdf -o out.pdf

cpdf -ocg-coalesce-on-name in.pdf -o out.pdf

In a PDF file, optional content groups are used to group graphical elements together, so they may appear or not, depending on the preference of the user. They are similar in some ways to layers in graphics illustration programs.

cpdf -ocg-list in.pdf

List the optional content groups in the PDF, one per line, to standard output.

cpdf -ocg-rename -ocg-rename-from <a> -ocg-rename-to <b> in.pdf -o out.pdf

Rename an optional content group.

cpdf -ocg-coalesce-on-name in.pdf -o out.pdf

Coalesce 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. Running -ocg-coalesce-on-name will merge the two into a single optional content group.

cpdf -ocg-order-all in.pdf -o out.pdf

Ensure that every optional content group appears in the order list.

Python Interface

 
# CHAPTER 16. Optional Content Groups 
 
def getOCGList(pdf): 
    """Return a list of Optional Content Groups in the given pdf as strings.""" 
 
def OCGRename(pdf, n_from, n_to): 
    """Rename an optional content group.""" 
 
def OCGOrderAll(pdf): 
    """Ensure that every optional content group appears in the OCG order list.""" 
 
def OCGCoalesce(pdf): 
    """Coalesce 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."""