'height' => 180,
),
'hqdefault' => array(
'width' => 480,
'height' => 360,
),
'sddefault' => array(
'width' => 640,
'height' => 480,
),
'maxresdefault' => array(
'width' => 1280,
'height' => 720,
)
);
//filter set resolution
$resolution = apply_filters('perfmatters_lazyload_youtube_thumbnail_resolution', 'hqdefault');
//finished youtube lazy output
$youtube_lazyload = '';
$youtube_lazyload.= '
';
$youtube_lazyload.= '
 .'/' . $resolution . '.jpg)
';
$youtube_lazyload.= '
';
$youtube_lazyload.= '
';
$youtube_lazyload.= '
![]()
', Utilities::get_atts_string($image_atts));
$html = str_replace($image[0], $new_image, $html);
}
continue;
}
}
//match all source tags inside the picture
preg_match_all('##isU', $picture[2], $sources, PREG_SET_ORDER);
if(!empty($sources)) {
//remove any duplicate sources
$sources = array_unique($sources, SORT_REGULAR);
foreach($sources as $source) {
//skip if exluded attribute was found
if(self::lazyload_excluded($source[1], self::lazyload_excluded_atts())) {
continue;
}
//migrate srcet
$new_source = preg_replace('/([\s"\'])srcset/i', '${1}data-srcset', $source[0]);
//migrate sizes
$new_source = preg_replace('/([\s"\'])sizes/i', '${1}data-sizes', $new_source);
//replace source in html
$html = str_replace($source[0], $new_source, $html);
}
}
else {
continue;
}
}
}
return $html;
}
//lazy load background images
private static function lazyload_background_images($html, $buffer) {
//match all elements with inline styles
//preg_match_all('#<(?div|figure|section|span|li)(\s+[^>]+[\'"\s]?style\s*=\s*[\'"].*?background-image.*?[\'"][^>]*)>#is', $buffer, $elements, PREG_SET_ORDER); //alternate to possibly filter some out that don't have background images???
preg_match_all('#<(?div|figure|section|span|li|a)(\s+[^>]*[\'"\s]?style\s*=\s*[\'"].*?[\'"][^>]*)>#is', $buffer, $elements, PREG_SET_ORDER);
if(!empty($elements)) {
foreach($elements as $element) {
//get element tag attributes
$element_atts = Utilities::get_atts_array($element[2]);
//dont check excluded if forced attribute was found
if(!self::lazyload_excluded($element[2], self::lazyload_forced_atts())) {
//skip if no-lazy class is found
if(!empty($element_atts['class']) && strpos($element_atts['class'], 'no-lazy') !== false) {
continue;
}
//skip if exluded attribute was found
if(self::lazyload_excluded($element[2], self::lazyload_excluded_atts())) {
continue;
}
}
//skip if no style attribute
if(!isset($element_atts['style'])) {
continue;
}
//match background-image in style string
preg_match('#(([^;\s])*background(-(image|url))?)\s*:\s*(\s*url\s*\((?[^)]+)\))\s*;?#is', $element_atts['style'], $url);
if(!empty($url)) {
$url['url'] = trim($url['url'], '\'" ');
//add lazyload class
$element_atts['class'] = !empty($element_atts['class']) ? $element_atts['class'] . ' ' . 'perfmatters-lazy' : 'perfmatters-lazy';
//remove background image url from inline style attribute
$element_atts['style'] = str_replace($url[0], '', $element_atts['style']);
//migrate src
$element_atts['data-bg'] = esc_url(trim(strip_tags(html_entity_decode($url['url'], ENT_QUOTES|ENT_HTML5)), '\'" '));
if(!empty($url[2])) {
$element_atts['data-bg-var'] = $url[1];
}
//build lazy element
$lazy_element = sprintf('<' . $element['tag'] . ' %1$s >', Utilities::get_atts_string($element_atts));
//replace element with placeholder
$html = str_replace($element[0], $lazy_element, $html);
unset($lazy_element);
}
else {
continue;
}
}
}
return $html;
}
//prep img tag for lazy loading
private static function lazyload_image($image) {
//if there are no attributes, return original match
if(empty($image[1])) {
return $image[0];
}
//get image attributes array
$image_atts = Utilities::get_atts_array($image[1]);
//get new attributes
if(empty($image_atts['src']) || (!self::lazyload_excluded($image[1], self::lazyload_forced_atts()) && ((!empty($image_atts['class']) && strpos($image_atts['class'], 'no-lazy') !== false) || self::lazyload_excluded($image[1], self::lazyload_excluded_atts()) || !empty($image_atts['fetchpriority'])))) {
return $image[0];
}
else {
//add lazyload class
$image_atts['class'] = !empty($image_atts['class']) ? $image_atts['class'] . ' ' . 'perfmatters-lazy' : 'perfmatters-lazy';
//migrate src
$image_atts['data-src'] = $image_atts['src'];
//add placeholder src
$width = !empty($image_atts['width']) ? $image_atts['width'] : 0;
$height = !empty($image_atts['height']) ? $image_atts['height'] : 0;
$image_atts['src'] = "data:image/svg+xml,%3Csvg%20xmlns='http://www.w3.org/2000/svg'%20width='" . $width . "'%20height='" . $height . "'%20viewBox='0%200%20" . $width . "%20" . $height . "'%3E%3C/svg%3E";
//migrate srcset
if(!empty($image_atts['srcset'])) {
$image_atts['data-srcset'] = $image_atts['srcset'];
unset($image_atts['srcset']);
}
//migrate sizes
if(!empty($image_atts['sizes'])) {
$image_atts['data-sizes'] = $image_atts['sizes'];
unset($image_atts['sizes']);
}
//unset existing loading attribute
if(isset($image_atts['loading'])) {
unset($image_atts['loading']);
}
}
//replace attributes
$output = sprintf('![]()
', Utilities::get_atts_string($image_atts));
//original noscript image
if(apply_filters('perfmatters_lazyload_noscript', true)) {
$output.= "";
}
return $output;
}
//lazy load css background images
private static function lazyload_css_background_images($html, $buffer) {
if(!empty(Config::$options['lazyload']['css_background_selectors'])) {
//match all selectors
preg_match_all('#<(?>div|section)(\s[^>]*?(' . implode('|', Config::$options['lazyload']['css_background_selectors']) . ').*?)>#i', $buffer, $selectors, PREG_SET_ORDER);
if(!empty($selectors)) {
foreach($selectors as $selector) {
$selector_atts = Utilities::get_atts_array($selector[1]);
$selector_atts['class'] = !empty($selector_atts['class']) ? $selector_atts['class'] . ' ' . 'perfmatters-lazy-css-bg' : 'perfmatters-lazy-css-bg';
//replace video attributes string
$selector_lazyload = str_replace($selector[1], ' ' . Utilities::get_atts_string($selector_atts), $selector[0]);
//replace video with placeholder
$html = str_replace($selector[0], $selector_lazyload, $html);
unset($selector_lazyload);
}
}
}
return $html;
}
//mark images inside parent exclusions as no-lazy
private static function lazyload_parent_exclusions($html, $buffer) {
if(!empty(Config::$options['lazyload']['lazy_loading_parent_exclusions'])) {
//match all selectors
preg_match_all('#<(div|section|figure)(\s[^>]*?(' . implode('|', Config::$options['lazyload']['lazy_loading_parent_exclusions']) . ').*?)>.*?#is', $buffer, $selectors, PREG_SET_ORDER);
if(!empty($selectors)) {
foreach($selectors as $selector) {
//match all img tags
preg_match_all('#]+?)\/?>#is', $selector[0], $images, PREG_SET_ORDER);
if(!empty($images)) {
//remove any duplicate images
$images = array_unique($images, SORT_REGULAR);
//loop through images
foreach($images as $image) {
$image_atts = Utilities::get_atts_array($image[1]);
$image_atts['class'] = !empty($image_atts['class']) ? $image_atts['class'] . ' ' . 'no-lazy' : 'no-lazy';
//replace video attributes string
$new_image = str_replace($image[1], ' ' . Utilities::get_atts_string($image_atts), $image[0]);
//replace video with placeholder
$html = str_replace($image[0], $new_image, $html);
unset($new_image);
}
}
}
}
}
return $html;
}
//get forced attributes
private static function lazyload_forced_atts() {
return apply_filters('perfmatters_lazyload_forced_attributes', array());
}
//get excluded attributes
private static function lazyload_excluded_atts() {
//base exclusions
$attributes = array(
'data-perfmatters-preload',
'gform_ajax_frame',
';base64'
);
//get exclusions added from settings
if(!empty(Config::$options['lazyload']['lazy_loading_exclusions']) && is_array(Config::$options['lazyload']['lazy_loading_exclusions'])) {
$attributes = array_unique(array_merge($attributes, Config::$options['lazyload']['lazy_loading_exclusions']));
}
return apply_filters('perfmatters_lazyload_excluded_attributes', $attributes);
}
//check for excluded attributes in attributes string
private static function lazyload_excluded($string, $excluded) {
if(!is_array($excluded)) {
(array) $excluded;
}
if(empty($excluded)) {
return false;
}
foreach($excluded as $exclude) {
if(strpos($string, $exclude) !== false) {
return true;
}
}
return false;
}
}