Create Links in Table Of Contents
This demo parses a table of contents of an existing PDF document and adds links to its entries.
The TOC is on page 2 of the example document.
After processing the example document with this script, the TOC entries are clickable links to their target pages.
PHP
<?php
use setasign\SetaPDF2\Core\Document;
use setasign\SetaPDF2\Core\Document\Action\GoToAction;
use setasign\SetaPDF2\Core\Document\Destination;
use setasign\SetaPDF2\Core\Document\Page\Annotation\LinkAnnotation;
use setasign\SetaPDF2\Core\Writer\HttpWriter;
use setasign\SetaPDF2\Extractor\Extractor;
use setasign\SetaPDF2\Extractor\Result\Collection;
use setasign\SetaPDF2\Extractor\Result\Word;
use setasign\SetaPDF2\Extractor\Strategy\WordStrategy;
// load and register the autoload function
require_once __DIR__ . '/../../../../../bootstrap.php';
$document = Document::loadByFilename(
$assetsDirectory . '/pdfs/Brand-Guide-without-links.pdf',
new HttpWriter('document.pdf', true)
);
$extractor = new Extractor($document);
$strategy = new WordStrategy();
$extractor->setStrategy($strategy);
$lines = [];
$tocStartPage = 2;
$tocEndPage = 2;
$offset = 2;
$pages = $document->getCatalog()->getPages();
for ($pageNo = $tocStartPage; $pageNo <= $tocEndPage; $pageNo++) {
/**
* @var Word[] $words
*/
$words = $extractor->getResultByPageNumber($pageNo);
/**
* @var $lines Collection[][]
*/
$lines[$pageNo] = [];
$line = new Collection();
/**
* @var Word $prevWord
*/
$prevWord = null;
foreach ($words AS $word) {
if ($prevWord) {
$prevBounds = $prevWord->getBounds();
$bounds = $word->getBounds();
$prevY = $prevBounds[0]->getLl()->getY();
$y = $bounds[0]->getLl()->getY();
// group by lines
if (abs($prevY - $y) > 4) {
$lines[$pageNo][] = $line;
$line = new Collection();
}
}
$line[] = $word;
$prevWord = $word;
}
if (count($line) > 0) {
$lines[$pageNo][] = $line;
$line = new Collection();
}
$annotations = $pages->getPage($pageNo)->getAnnotations();
foreach ($lines[$pageNo] AS $i => $line) {
// reconstruct line text and get max/min bounds
$lineText = '';
$llx = $lly = $urx = $ury = null;
foreach ($line as $word) {
$lineText .= $word->getString() . ' ';
}
$lineText = trim($lineText);
// extract target page number
if (!preg_match("/(\d+)$/u", $lineText, $m)) {
continue;
}
$linkToPageNo = $m[1];
$action = new GoToAction(Destination::createByPage($pages->getPage($linkToPageNo + $offset)));
$bounds = $line->getBounds();
$ll = $bounds[0]->getLl();
$ur = $bounds[0]->getUr();
$annotation = new LinkAnnotation(
[$ll->getX(), $ll->getY(), $ur->getX(), $ur->getY()],
$action
);
$annotations->add($annotation);
}
}
$document->save()->finish();