Filter Same Area Several Times
If a filter is directly attached to a strategy each text-item will be checked against it and will exist only once
in the result.
If e.g. two rectangle filters are combine in a multifilter but share the same or overlapping area, only one
instance will get the text-items. This can lead to unexpected results.
This demo shows a way, to resolve all text-items once while filter them afterward several times to identify a document type. The rectangle filters use almost the same area.
PHP
<?php
use setasign\SetaPDF2\Core\Document;
use setasign\SetaPDF2\Core\Geometry\Rectangle;
use setasign\SetaPDF2\Extractor\Extractor;
use setasign\SetaPDF2\Extractor\Filter\RectangleFilter;
use setasign\SetaPDF2\Extractor\Strategy\ExactPlainStrategy;
// load and register the autoload function
require_once __DIR__ . '/../../../../../bootstrap.php';
$files = [
$assetsDirectory . '/pdfs/camtown/Terms-and-Conditions.pdf',
$assetsDirectory . '/pdfs/etown/Laboratory-Report.pdf',
$assetsDirectory . '/pdfs/lenstown/Subscription-tekMag.pdf',
$assetsDirectory . '/pdfs/Brand-Guide.pdf'
];
$path = displayFiles($files);
$document = Document::loadByFilename($path);
$extractor = new Extractor($document);
$strategy = new ExactPlainStrategy();
$extractor->setStrategy($strategy);
// we prepare an initial filter to reduce the text item count
$mainFilter = new RectangleFilter(new Rectangle(0, 752, 596, 649));
$strategy->setFilter($mainFilter);
$filters = [
'Laboratory Report' => new RectangleFilter(new Rectangle(36, 712, 240, 674)),
'Terms and Conditions' => new RectangleFilter(new Rectangle(32, 716, 286, 671)),
'Subscription tekMag' => new RectangleFilter(new Rectangle(31, 713, 262, 672))
];
$page = $document->getCatalog()->getPages()->getPage(1);
$textItems = $extractor->getTextItemsByPage($page);
foreach ($filters as $filterName => $filter) {
// tell the filter about the page, the text-items came from
$filter->setPage($page);
// now we filter the existing text-items by the individual filter
$result = $strategy->getResultByTextItems($textItems, $filter);
if ($result === $filterName) {
$match = $filterName;
break;
}
}
switch ($match ?? null) {
case 'Laboratory Report':
echo 'This document is a laboratory report!';
// ...process it
break;
case 'Terms and Conditions':
echo 'This document shows Terms and Conditions!';
// ...process it
break;
case 'Subscription tekMag':
echo 'This document is a subscription form to the tekMag!';
// ...process it
break;
default:
echo 'Sorry, but I cannot recognize the document type.';
}