static function init()
{
if (is_admin()) {
return;
}
if (!apply_filters('lazyload_is_enabled', true)) {
self::$enabled = false;
return;
}
add_action('wp_enqueue_scripts', array(__CLASS__, 'add_scripts'));
add_action('wp_head', array(__CLASS__, 'setup_filters'), 9999);
// we don't really want to modify anything in <head> since it's mostly all metadata, e.g. OG tags
}
/**
* Filter the image tag to implement lazy loading support for avatars.
*
* @param string $image_format
* @return string
*/
public static function social_get_avatar_image_format($image_format)
{
if (class_exists('LazyLoad_Images')) {
// would be great if the plugin provided an API for this, until then we'll copy the code
$placeholder_image = apply_filters('lazyload_images_placeholder_image', LazyLoad_Images::get_url('images/1x1.trans.gif'));
$image_format = '<img alt="%1$s" src="' . esc_url($placeholder_image) . '" data-lazy-src="%2$s" class="avatar avatar-%3$s photo %4$s" height="%3$s" width="%3$s" /><noscript>' . $image_format . '</noscript>';
}
return $image_format;
}
// Note: this needs to be added so that it's executed after the hook added by Jetpack
add_filter('post_gallery', array(__CLASS__, 'add_image_placeholders'), 1002, 2);
}
static function add_scripts()
{
wp_enqueue_script('wpcom-lazy-load-images', self::get_url('js/lazy-load.js'), array('jquery', 'jquery-lazyload'), self::version, true);
wp_enqueue_script('jquery-lazyload', self::get_url('js/jquery.lazyload.min.js'), array('jquery'), self::version, true);
}
static function add_image_placeholders($val, $attrs)
{
// Don't lazy-load if the content has already been run through previously
if (false !== strpos($val, 'data-lazy-src')) {
return $val;
}
// It's possible to filter based on gallery type here, for example
if ('square' !== $attrs['type']) {
return $val;
}
// This is a pretty simple regex, but it works
// Remember to put data-lazy-src as the data attribute if you want to
// serve your images through photon. They work locally too, though
$val = preg_replace('#<img([^>]+?)src=[\'"]?([^\'"\\s>]+)[\'"]?([^>]*)>#', sprintf('<img${1}data-lazy-src="${2}"${3}><noscript><img${1}src="${2}"${3}></noscript>', $placeholder_image), $val);
return $val;
}
static function get_url($path = '')
{
return plugins_url(ltrim($path, '/'), __FILE__);
}
}
LazyLoad_Images::init();
}
function lazyload_images_add_placeholders($content)
{
return LazyLoad_Images::add_image_placeholders($content);
}
