```{index} single: add_outline (Cairo::PdfSurface) ``` ```{index} single: Cairo::PdfSurface::add_outline ``` # add_outline Adds an entry to the PDF's document outline (its bookmark tree) and returns the entry's id, for use as the parent of further entries. my $id = $pdf->add_outline( Cairo::PdfSurface::OUTLINE_ROOT, 'Chapter 1', "page=1", 0); $pdf->add_outline($id, 'Section 1.1', "page=2", 0); `$parent_id` is `Cairo::PdfSurface::OUTLINE_ROOT` for a top-level entry, `$link_attribs` a string of `name=value` pairs saying where the entry points, and `$flags` a plain INTEGER bitmask - unlike the other enumerated arguments in this module, it is not a name. Needs cairo 1.16 or newer; on an older library the call dies saying so. Wraps `cairo_pdf_surface_add_outline`.