PDF/A support

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

class FPDFA extends FPDF
{
    protected $n_colorprofile;
    protected $n_metadata;

    protected function _putcolorprofile()
    {
        $icc = file_get_contents(__DIR__.'/sRGB2014.icc');
        if(!$icc)
            $this->Error('Could not load the ICC profile');
        $this->_newobj();
        $this->n_colorprofile = $this->n;
        $this->_put('<<');
        $this->_put('/Length '.strlen($icc));
        $this->_put('/N 3');
        $this->_put('>>');
        $this->_putstream($icc);
        $this->_put('endobj');
    }

    function _getxmpdescription($prefix, $ns, $body)
    {
        return sprintf("\t<rdf:Description rdf:about=\"\" xmlns:%s=\"%s\">\n%s\t</rdf:Description>\n", $prefix, $ns, $body);
    }

    function _getxmpsimple($tag, $value)
    {
        $value = htmlspecialchars($value, ENT_XML1, 'UTF-8');
        return sprintf("\t\t<%s>%s</%s>\n", $tag, $value, $tag);
    }

    function _getxmpseq($tag, $value)
    {
        $value = htmlspecialchars($value, ENT_XML1, 'UTF-8');
        return sprintf("\t\t<%s>\n\t\t\t<rdf:Seq>\n\t\t\t\t<rdf:li>%s</rdf:li>\n\t\t\t</rdf:Seq>\n\t\t</%s>\n", $tag, $value, $tag);
    }

    function _getxmpalt($tag, $value)
    {
        $value = htmlspecialchars($value, ENT_XML1, 'UTF-8');
        return sprintf("\t\t<%s>\n\t\t\t<rdf:Alt>\n\t\t\t\t<rdf:li xml:lang=\"x-default\">%s</rdf:li>\n\t\t\t</rdf:Alt>\n\t\t</%s>\n", $tag, $value, $tag);
    }

    function _putmetadata()
    {
        $pdf = $this->_getxmpsimple('pdf:Producer', $this->metadata['Producer']);
        if(isset($this->metadata['Keywords']))
            $pdf .= $this->_getxmpsimple('pdf:Keywords', $this->metadata['Keywords']);

        $date = @date('c', $this->CreationDate);
        $xmp = $this->_getxmpsimple('xmp:CreateDate', $date);
        if(isset($this->metadata['Creator']))
            $xmp .= $this->_getxmpsimple('xmp:CreatorTool', $this->metadata['Creator']);

        $dc = '';
        if(isset($this->metadata['Author']))
            $dc .= $this->_getxmpseq('dc:creator', $this->metadata['Author']);
        if(isset($this->metadata['Title']))
            $dc .= $this->_getxmpalt('dc:title', $this->metadata['Title']);
        if(isset($this->metadata['Subject']))
            $dc .= $this->_getxmpalt('dc:description', $this->metadata['Subject']);

        $pdfaid = $this->_getxmpsimple('pdfaid:part', '3');
        $pdfaid .= $this->_getxmpsimple('pdfaid:conformance', 'B');

        $s = '<?xpacket begin="" id="W5M0MpCehiHzreSzNTczkc9d"?>'."\n";
        $s .= '<rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#">'."\n";
        $s .= $this->_getxmpdescription('pdf', 'http://ns.adobe.com/pdf/1.3/', $pdf);
        $s .= $this->_getxmpdescription('xmp', 'http://ns.adobe.com/xap/1.0/', $xmp);
        if($dc)
            $s .= $this->_getxmpdescription('dc', 'http://purl.org/dc/elements/1.1/', $dc);
        $s .= $this->_getxmpdescription('pdfaid', 'http://www.aiim.org/pdfa/ns/id/', $pdfaid);
        $s .= '</rdf:RDF>'."\n";
        $s .= '<?xpacket end="r"?>';

        $this->_newobj();
        $this->n_metadata = $this->n;
        $this->_put('<<');
        $this->_put('/Type /Metadata');
        $this->_put('/Subtype /XML');
        $this->_put('/Length '.strlen($s));
        $this->_put('>>');
        $this->_putstream($s);
        $this->_put('endobj');
    }

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

    function _putcatalog()
    {
        parent::_putcatalog();
        $oi = '<</Type /OutputIntent /S /GTS_PDFA1 ';
        $oi .= '/OutputConditionIdentifier (sRGB2014.icc) /Info (sRGB2014.icc) /RegistryName (http://www.color.org) ';
        $oi .= '/DestOutputProfile '.$this->n_colorprofile.' 0 R>>';
        $this->_put('/OutputIntents ['.$oi.']');
        $this->_put('/Metadata '.$this->n_metadata.' 0 R');
    }

    protected function _putheader()
    {
        $this->_put('%PDF-1.4');
        $this->_put("%\xE2\xE3\xCF\xD3");
    }

    function _puttrailer()
    {
        parent::_puttrailer();
        $id = uniqid();
        $this->_put("/ID [($id)($id)]");
    }

    function _enddoc()
    {
        if(!isset($this->metadata['Producer']))
            $this->Error('Unsupported FPDF version');
        foreach($this->fonts as $font)
        {
            if($font['type']=='Core')
                $this->Error('All fonts must be embedded in PDF/A');
        }
        $this->CreationDate = time();
        parent::_enddoc();
    }
}
?>

<?php
require('fpdfa.php');
define('FPDF_FONTPATH', '.');

$pdf = new FPDFA();
$pdf->AddFont('DejaVuSansCondensed', '', 'DejaVuSansCondensed.php');
$pdf->SetFont('DejaVuSansCondensed', '', 16);
$pdf->AddPage();
$pdf->Write(10, 'This PDF is PDF/A-3b compliant.');
$pdf->Output();
?>