Navigate PDF outline tree in Ruby

To navigate an outline tree and print its result.

def PrintIndent(item)
	indent = item.GetIndent() - 1
	i = 0
	while i < indent do
		print "  "
		i = i + 1
	end
end
def PrintOutlineTree (item)
	while item.IsValid() do
		PrintIndent(item)
		if item.IsOpen()
			print( "- " + item.GetTitle() + " ACTION -> ")
		else
			print("+ " + item.GetTitle() + " ACTION -> ")
		end  
		if item.HasChildren() 
			PrintOutlineTree(item.GetFirstChild())
		end
		item = item.GetNext()
	end
end
doc = PDFDoc.new(filename)
root = doc.GetFirstBookmark()
PrintOutlineTree(root)

Read, add, edit PDF outlines and bookmarks
Full code sample which illustrates how to read and edit existing outline items and create new bookmarks using the high-level API.

A PDF document may display a document outline on the screen, allowing the user to navigate interactively from one part of the document to another. The outline consists of a tree-structured hierarchy of Bookmarks (sometimes called outline items), which serve as a "visual table of contents" to display the document's structure to the user.

Each Bookmark has a title that appears on screen, and an Action that specifies what happens when a user clicks on the Bookmark. The typical Action for a user-created Bookmark is to move to another location in the current document — although any Action can be specified.