inlie.php

<?php
function clean_da_svg($svg){
    $remover[] = 'xmlns:a="http://ns.adobe.com/AdobeSVGViewerExtensions/3.0/"';
    $remover[] = 'xmlns:xlink="http://www.w3.org/1999/xlink"';
    $remover[] = 'x="0px" y="0px"';
    $remover[] = '<defs></defs>';
    $remover[] = 'version="1.1"';
    $remover[] = "\r";
    $remover[] = "\n";
    $remover[] = "\r\n";
    $remover[] = "\n\r";
    $remover[] = "\r\r";
    $remover[] = "\n\n";
    $remover[] = "\r\n\r\n";
    $remover[] = PHP_EOL;
    $str = (string) str_replace($remover, '', $svg);
    $str = trim(preg_replace('/\s+/', ' ', $str));
    $str = substr($str, 255);
    $str = str_replace('<defs></defs>', '', $str);
    return $str;
}
$selectors = array(); //array que vai conter todas os seletores(imagens)
$css_rules = array(); //array que vai conter uma declaracao pra cada imagem
$pre_selector = "."; //por exemplo: .icon  ou #teste .icons 
$folder = "sprite/xtra/"; //pasta pra procurar os arquivos
$files = glob($folder.'*.{gif,jpg,png,svg}', GLOB_BRACE); //arquivos possiveis
foreach($files as $file) {
    $file_info = pathinfo($file);
        if($file_info['extension'] == "svg"){
            $mime_type = 'svg+xml';
            $xml = simplexml_load_file($file);
            $attr = $xml->attributes();
            $size['width'] = $attr->width;
            $size['height'] = $attr->height;
	        $base64 = str_replace("%2F", "/", rawurlencode(clean_da_svg(file_get_contents($file))));
            $encode = 'charset=US-ASCII';
        } else {
            $size_tmp = getimagesize($file);
            $mime_type = $file_info['extension'];
            $size['width'] = $size_tmp[0]."px";
            $size['height'] = $size_tmp[1]."px";                    
	        $base64 = base64_encode(file_get_contents($file));
            $encode = 'base64';
        }

    $css_selector = $pre_selector.$file_info['extension'].'-'.$file_info['filename'];//css selector com a possibilidade de um pre-seletor
    if($file_info['extension'] == "svg")//se não for SVG não precisa background-size nem no-repeat
        $selectors[] = $css_selector;
    if(!strpos($css_selector, "-repeat")) {
        $css_rules[]= $css_selector. " {width:".$size['width'].";height:".$size['height'].";background-image:url('data:image/$mime_type;$encode,".$base64."');}";
    } else {
        $css_rules[]= $css_selector. " {background-repeat:repeat;background-image:url('data:image/$mime_type;$encode,".$base64."');}";
    }
}
if(count($selectors))//se não tiver svg não imprime
    echo implode(",", $selectors) . "{background-size:100%;background-repeat:no-repeat;display:block}".PHP_EOL;
foreach($css_rules as $css){
    echo $css .PHP_EOL;
}