Create a PDF-File with Annotations showing up in Adobe Reader with a checked checkbox in the Annotation-List.

create_annotation.php

<?php
// Requires PDFlib >= 8.0.0
header('Content-Type: application/pdf');
$pdf = new PDFlib();
$pdf->begin_document('','');
$pdf->begin_page_ext(100,100,'');
$pdf->create_annotation(10,40,20,50, 'text', 'contents={testcontent} name=1 title={foo} popup=2 annotcolor={rgb 1 1 0}');
$pdf->create_annotation(10,40,20,50, 'popup', 'name=2 parentname=1');
$pdf->create_annotation(10,40,20,50,'text','contents={Marked festgelegt von foo} name=3 custom={{key=State type=string value=Marked} {key=StateModel type=string value=Marked}} title={foo}  popup=4 inreplyto=1 annotcolor={rgb 1 1 0}');
$pdf->create_annotation(10,40,20,50, 'popup', 'name=4 parentname=3');
$pdf->end_page_ext('');
$pdf->end_document('');
echo $pdf->get_buffer();