AddArticleThread

Page-level navigation, document properties

Description

Creates one PDF article thread whose beads define the logical reading sequence across one or more page rectangles

The method writes the catalog /Threads array, the thread /F entry, circular /N and /V bead links, page references, rectangles and each page's /B array as required by ISO 32000-1 §12.4.3

Syntax

Function TPDFlib.AddArticleThread(Const Info: TPDFlibArticleThreadInfo; Const Beads: Array Of TPDFlibArticleBead): Integer;

Parameters

Info	Optional title, author, subject, keywords and PDF creation-date metadata; `BeadCount` is ignored when writing
Beads	One or more page rectangles in article reading order

Return value

Returns the new one-based article-thread index, or 0 when the document, page number, rectangle or an existing article container is invalid

Remarks

Every rectangle uses unscaled PDF user-space coordinates ordered as left, bottom, right and top

Input is validated before objects are added, repeated pages reuse stable page references and the selected page is preserved

DeletePages removes empty threads and repairs the circular links of surviving threads

Example

Info.Title := 'Feature story';
Info.Author := 'Editorial desk';
SetLength(Beads, 2);
Beads[0].Page := 1;
Beads[0].Left := 72;
Beads[0].Bottom := 360;
Beads[0].Right := 288;
Beads[0].Top := 720;
Beads[1].Page := 3;
Beads[1].Left := 72;
Beads[1].Bottom := 360;
Beads[1].Right := 288;
Beads[1].Top := 720;
ThreadIndex := PDF.AddArticleThread(Info, Beads);