Loop through SVG elements with PHP [duplicate]

Question

How can I loop through SVG elements with PHP?

<?php

$svgString = '<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" style="overflow: hidden; position: relative;" width="9140" version="1.1" height="3050">
<rect x="0" y="0" width="9140" height="3050" r="0" rx="0" ry="0" fill="#FFFF00" stroke="#000"/>
<image x="-101.5" y="-113.5" width="203" height="227" xlink:href="1.jpg" stroke-width="1"></image>
<image x="-201.5" y="-213.5" width="103" height="127" xlink:href="2.jpg" stroke-width="1"></image>
</svg>';

$svg = new SimpleXMLElement( $svgString );
$result = $svg->xpath('//image');
echo count( $result ); 
for ($i = 0; $i < count($result); $i++) 
{
    var_dump( $result[$i] );
}

count($result) returns 0 so the loop is omitted.

What am I doing wrong?

Answer 1

The svg document is using a default namespace:

<svg xmlns="http://www.w3.org/2000/svg" ...

Further, the xlink namespace is used for image@href attributes. You need to register the default namespace and the xlink namespace using registerXPathNamespace():

$svg = new SimpleXMLElement( $svgString );

// register the default namespace
$svg->registerXPathNamespace('svg', 'http://www.w3.org/2000/svg');
// required for the <image xlink:href=" ... attribute
$svg->registerXPathNamespace('xlink', 'http://www.w3.org/1999/xlink');

// use the prefixes in the query
$result = $svg->xpath('//svg:image/@xlink:href');

echo count( $result ); // output: '2'
for ($i = 0; $i < count($result); $i++)
{
    var_dump( $result[$i] );
}

Answer 2

Oh joy, namespaces:

$svg = new SimpleXMLElement( $svg );
$namespaces = $svg->getDocNamespaces();
$svg->registerXPathNamespace('__nons', $namespaces['']);

$result = $svg->xpath('//__nons:image');