<?php
class InlineImages {
/** IE cannot display inline data larger than 32KiB
also processing large images would take too much time */
const SIZE_LIMIT = 32768;
/** Regular expression to find URL definitions in CSS file */
const REGEXP = '/(background(-image)?|list-style(-image)?|cursor):\ ?url\(([\'\"]?([^\'\)]+)[\'\"]?)\)/im';
const REGIND = 5; //index of matching parenthesis where URL can be found
/** Quotation character for CSS url() function
- either ' or " (just in case you want to change it ;) */
const QUOTE = '\''; //
private $path;
/**
* Creates new instance of CSS image replacer
*
* @param [String] path where to look for images - URLs in CSS must be relative to this path!
*/
public function __construct($path) {
$this->path = $path;
}
/**
* Replace images in CSS file with inline data
*
* @param [String] CSS file content
* @return [String] replaced CSS
*/
public function process($data) {
if (false !== preg_match_all(self::REGEXP, $data, $matches)) {
$images = array();
foreach ($matches[self::REGIND] as $index => $url) {
$key = $matches[self::REGIND - 1][$index]; //URL including quotes (that must be removed from file as well)
$filename = realpath($this->path . $url);
if (false !== $filename && self::SIZE_LIMIT > filesize($filename)) {
//get Base64-encoded content of the file
$file = file_get_contents($filename);
$base64 = base64_encode($file);
//get Type of the file
if (class_exists('finfo')) { //optional, requires PHP extension FileInfo (preferred)
$finfo = new finfo(FILEINFO_MIME);
$mime = $finfo->file($filename);
$mime = explode(';', $mime)[0]; //returns also charset
}
elseif (function_exists('mime_content_type')) { //optional, requires PHP extension MimeType (deprecated)
$mime = mime_content_type($filename);
} else { //old way of detecting MIME from file extension
preg_match('/\.([^\.]+)$/', $filename, $mime);
$mime = 'image/' . $mime[1];
}
//save the content
if (self::SIZE_LIMIT > count($base64)) { //base64 increses file size by ~20% - check the limit again
$images[$key] = self::QUOTE . 'data:' . $mime . ';base64,' . $base64 . self::QUOTE;
}
}
}
if (count($images)) {
$data = strtr($data, $images);
}
}
return $data;
}
}