Add-On Bookmarks

<?php
require('fpdf.php');

class PDF_Bookmark extends FPDF
{
protected $outlines = array();
protected $outlineRoot;

function Bookmark($txt, $isUTF8=false, $level=0, $y=0)
{
    if(!$isUTF8)
        $txt = $this->_UTF8encode($txt);
    if($y==-1)
        $y = $this->GetY();
    $this->outlines[] = array('t'=>$txt, 'l'=>$level, 'y'=>($this->h-$y)*$this->k, 'p'=>$this->PageNo());
}

function _putbookmarks()
{
    $nb = count($this->outlines);
    if($nb==0)
        return;
    $lru = array();
    $level = 0;
    foreach($this->outlines as $i=>$o)
    {
        if($o['l']>0)
        {
            $parent = $lru[$o['l']-1];
            // Set parent and last pointers
            $this->outlines[$i]['parent'] = $parent;
            $this->outlines[$parent]['last'] = $i;
            if($o['l']>$level)
            {
                // Level increasing: set first pointer
                $this->outlines[$parent]['first'] = $i;
            }
        }
        else
            $this->outlines[$i]['parent'] = $nb;
        if($o['l']<=$level && $i>0)
        {
            // Set prev and next pointers
            $prev = $lru[$o['l']];
            $this->outlines[$prev]['next'] = $i;
            $this->outlines[$i]['prev'] = $prev;
        }
        $lru[$o['l']] = $i;
        $level = $o['l'];
    }
    // Outline items
    $n = $this->n+1;
    foreach($this->outlines as $i=>$o)
    {
        $this->_newobj();
        $this->_put('<</Title '.$this->_textstring($o['t']));
        $this->_put('/Parent '.($n+$o['parent']).' 0 R');
        if(isset($o['prev']))
            $this->_put('/Prev '.($n+$o['prev']).' 0 R');
        if(isset($o['next']))
            $this->_put('/Next '.($n+$o['next']).' 0 R');
        if(isset($o['first']))
            $this->_put('/First '.($n+$o['first']).' 0 R');
        if(isset($o['last']))
            $this->_put('/Last '.($n+$o['last']).' 0 R');
        $this->_put(sprintf('/Dest [%d 0 R /XYZ 0 %.2F null]', $this->PageInfo[$o['p']]['n'], $o['y']));
        $this->_put('/Count 0>>');
        $this->_put('endobj');
    }
    // Outline root
    $this->_newobj();
    $this->outlineRoot = $this->n;
    $this->_put('<</Type /Outlines /First '.$n.' 0 R');
    $this->_put('/Last '.($n+$lru[0]).' 0 R>>');
    $this->_put('endobj');
}

function _putresources()
{
    parent::_putresources();
    $this->_putbookmarks();
}

function _putcatalog()
{
    parent::_putcatalog();
    if(count($this->outlines)>0)
    {
        $this->_put('/Outlines '.$this->outlineRoot.' 0 R');
        $this->_put('/PageMode /UseOutlines');
    }
}
}
?>

<?php
require('bookmark.php');

$pdf = new PDF_Bookmark();
$pdf->SetFont('Arial', '', 15);
// Page 1
$pdf->AddPage();
$pdf->Bookmark('Page 1', false);
$pdf->Bookmark('Paragraph 1', false, 1, -1);
$pdf->Cell(0, 6, 'Paragraph 1');
$pdf->Ln(50);
$pdf->Bookmark('Paragraph 2', false, 1, -1);
$pdf->Cell(0, 6, 'Paragraph 2');
// Page 2
$pdf->AddPage();
$pdf->Bookmark('Page 2', false);
$pdf->Bookmark('Paragraph 3', false, 1, -1);
$pdf->Cell(0, 6, 'Paragraph 3');
$pdf->Output();
?>