Perl Requires Chilkat v11.7.0+

Get Every Occurrence of a Label in a PDF

See more PDF Text Extraction Examples

Demonstrates the "labelOccurrence" option. When the same label appears more than once (for example "Total:" on each of several receipts), "first" (the default) uses the first occurrence, "all" returns every occurrence with its page, and a number selects one occurrence. Perl

use chilkat();

$success = 0;

#  This example requires the Chilkat API to have been previously unlocked.
#  See Global Unlock Sample for sample code.

#  The PDF used in this example (three receipts, one per page) is available at three_receipts.pdf

$pdf = chilkat::CkPdf->new();
$success = $pdf->LoadFile("qa_data/pdf/three_receipts.pdf");
if ($success == 0) {
    print $pdf->lastErrorText() . "\r\n";
    exit;
}

$json = chilkat::CkJsonObject->new();
$jsonOut = chilkat::CkJsonObject->new();

#  Each of the three pages is a receipt with a "Total:" line.
$json->UpdateString("label","Total");
$json->UpdateString("labelValue","right");

#  By default only the first occurrence (in reading order) is used.
$success = $pdf->ExtractText("text",$json,$jsonOut);
if ($success == 0) {
    print $pdf->lastErrorText() . "\r\n";
    exit;
}

print "First total: " . $jsonOut->stringOf("text") . "\r\n";

#  labelOccurrence "all" returns every occurrence.  The "text" member holds the values joined
#  by line breaks, and labelMatches has one entry per occurrence with its page.
$json->UpdateString("labelOccurrence","all");
$success = $pdf->ExtractText("text",$json,$jsonOut);
if ($success == 0) {
    print $pdf->lastErrorText() . "\r\n";
    exit;
}

$i = 0;
$count_i = $jsonOut->SizeOfArray("labelMatches");
while ($i < $count_i) {
    $jsonOut->put_I($i);
    print "Page " . $jsonOut->IntOf("labelMatches[i].page") . " total: " . $jsonOut->stringOf("labelMatches[i].text") . "\r\n";
    $i = $i + 1;
}

#  A number selects one occurrence: 2 is the second.
$json->UpdateInt("labelOccurrence",2);
$success = $pdf->ExtractText("text",$json,$jsonOut);
if ($success == 0) {
    print $pdf->lastErrorText() . "\r\n";
    exit;
}

print "Second total: " . $jsonOut->stringOf("text") . "\r\n";

#  The occurrences are counted over the selected pages, so combining "pages" with the label
#  is another way to pick one receipt:
$json->UpdateString("labelOccurrence","first");
$json->UpdateString("pages","3");
$json->UpdateString("label","Receipt No.");
$success = $pdf->ExtractText("text",$json,$jsonOut);
if ($success == 0) {
    print $pdf->lastErrorText() . "\r\n";
    exit;
}

print "Receipt number on page 3: " . $jsonOut->stringOf("text") . "\r\n";

#  Sample output:

#  First total: $19.86
#  Page 1 total: $19.86
#  Page 2 total: $17.34
#  Page 3 total: $23.62
#  Second total: $17.34
#  Receipt number on page 3: 1003