Perl Graphics Programming

PDF::API2::Outline

An Outline object provides the user agent with a linked table of contents that may be displayed alongside the document and used for navigation. In Adobe’s Acrobat Reader, outlines are displayed in a frame called the Bookmark frame; this section sticks with the term “outline.”

To create an outline, you must first create a root outline entry with the outlines( ) constructor, which returns a new PDF::API2::Outline object. Once the root is created, add outline entries with the outline( ) method; this also returns Outline objects. You can create a hierarchy of outline entries using the outline( ) method. Example 12-5 creates a PDF document with 20 pages, divided into 5 sections of 4 pages each. As each page is created, a new outline entry is added, and the entry is linked to the page with the dest( ) method.

Example 12-5. Adding an outline to a PDF document

#!/usr/bin/perl -w # # Example 12-5. Create a bookmark frame use strict; use PDF::API2; # Used to generate the PDF output # Create a new top-level document my $pdf = PDF::API2->new( ); # Initialize the root of the outline tree my $outline_root = $pdf->outlines( ); # Use Helvetica throughout my $font = $pdf->corefont('Helvetica'); my ($page, $text); # Create four sections foreach my $s (1..4) { # Add an entry for each section. Each section has # suboutline entries my $section = $outline_root->outline( ); $section->title("Section $s"); # Add five pages for each section foreach my $n (1..5) { # Draw some text on the page ...