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. UTF8.
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.