PHP ActiveX Requires Chilkat v11.7.0+

Remove PDF Objects Nothing Refers To

See more PDF Optimization Examples

Demonstrates removeUnreferenced. When a page, an image or a whole section is replaced in an editor, the objects it used often stay in the file with nothing pointing at them any more. They are not old revisions -- they are in the current revision, simply unreachable -- so only a reachability walk from the document catalog finds them. In a publication assembled over several editing passes this is frequently the largest single saving. PHP ActiveX

<?php

$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 is available at watersense_accomplishments.pdf

$pdf = new COM("Chilkat.Pdf");
$success = $pdf->LoadFile('qa_data/pdf/watersense_accomplishments.pdf');
if ($success == 0) {
    print $pdf->LastErrorText . "\n";
    exit;
}

$json = new COM("Chilkat.JsonObject");
$jsonOut = new COM("Chilkat.JsonObject");
$success = $pdf->Optimize('audit',$json,$jsonOut);
if ($success == 0) {
    print $pdf->LastErrorText . "\n";
    exit;
}

print 'fileSize: ' . $jsonOut->IntOf('fileSize') . "\n";
print 'removeUnreferenced would save: ' . $jsonOut->IntOf('estimatedSavings.removeUnreferenced') . "\n";

//  Optimize with the defaults and see how many objects were actually dropped.
$success = $pdf->Optimize('optimize',$json,$jsonOut);
if ($success == 0) {
    print $pdf->LastErrorText . "\n";
    exit;
}

$success = $pdf->WriteFile('qa_output/watersense_optimized.pdf');
if ($success == 0) {
    print $pdf->LastErrorText . "\n";
    exit;
}

print 'objects removed: ' . $jsonOut->IntOf('actions.removeUnreferenced.count') . "\n";
print 'bytes saved:     ' . $jsonOut->IntOf('actions.removeUnreferenced.bytesSaved') . "\n";

//  Nothing a page needs is ever removed: the walk starts at the document catalog and follows every
//  reference, including the ones in annotations, the structure tree, named destinations and the
//  optional-content configuration.
print 'pages after: ' . $pdf->NumPages . "\n";

?>