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<?php |
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if ( ! defined( 'ABSPATH' ) ) return; |
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/* |
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* LSX Lazy Load Images Class |
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* |
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* add_filters availables: |
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* lsx_lazyload_is_enabled |
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* lsx_lazyload_placeholder_image |
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* |
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* apply_filters availables: |
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* lsx_lazyload_filter_images |
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* |
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* Currently filtering: |
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* the_content |
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* widget_text |
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* post_thumbnail_html |
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* get_avatar |
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* envira_gallery_output_image |
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*/ |
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class LSX_LazyLoadImages { |
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protected static $enabled = true; |
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protected static $noscript_id = 0; |
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protected static $noscripts = array(); |
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static function init() { |
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if ( is_admin() ) |
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return; |
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if ( get_theme_mod( 'lsx_lazyload_status', '1' ) === false ) { |
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self::$enabled = false; |
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return; |
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} |
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if ( ! apply_filters( 'lsx_lazyload_is_enabled', true ) ) { |
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self::$enabled = false; |
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return; |
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} |
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add_action( 'wp_enqueue_scripts', array( __CLASS__, 'add_scripts' ) ); |
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add_action( 'wp_head', array( __CLASS__, 'setup_filters' ), 9999 ); |
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add_filter( 'wp_kses_allowed_html', array( __CLASS__, 'kses_allowed_html' ), 10, 2 ); |
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add_filter( 'kses_allowed_protocols', array( __CLASS__, 'kses_allowed_protocols' ) ); |
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} |
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static function setup_filters() { |
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// WordPress |
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add_filter( 'the_content', array( __CLASS__, 'filter_images' ), 200 ); |
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add_filter( 'widget_text', array( __CLASS__, 'filter_images' ), 200 ); |
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add_filter( 'post_thumbnail_html', array( __CLASS__, 'filter_images' ), 200 ); |
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add_filter( 'get_avatar', array( __CLASS__, 'filter_images' ), 200 ); |
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// LSX |
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add_filter( 'lsx_lazyload_filter_images', array( __CLASS__, 'filter_images' ), 200 ); |
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// Envira Gallery |
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add_filter( 'envira_gallery_output_image', array( __CLASS__, 'filter_images' ), 200 ); |
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} |
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static function add_scripts() { |
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wp_enqueue_script( 'lazysizes', get_template_directory_uri() .'/js/vendor/lazysizes.min.js', array( 'jquery' ), null, true ); |
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// Plugin that enables use lazysizes in brackground images |
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//wp_enqueue_script( 'lazysizes', get_template_directory_uri() .'/js/vendor/ls.unveilhooks.min.js', array( 'jquery', 'lazysizes' ), null, true ); |
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} |
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static function filter_images( $content ) { |
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if ( ! self::is_enabled() ) { |
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return $content; |
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} |
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$http_user_agent = sanitize_text_field( wp_unslash( $_SERVER['HTTP_USER_AGENT'] ) ); |
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$http_user_agent = ! empty( $http_user_agent ) ? $http_user_agent : ''; |
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if ( is_feed() |
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|| is_preview() |
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|| intval( get_query_var( 'print' ) ) == 1 |
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|| intval( get_query_var( 'printpage' ) ) == 1 |
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|| strpos( $http_user_agent, 'Opera Mini' ) !== false |
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) { |
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return $content; |
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} |
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$skip_images_regex = '/class=".*(lazyload|disable-lazyload).*"/'; |
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$placeholder_image = apply_filters( 'lsx_lazyload_placeholder_image', 'data:image/gif;base64,R0lGODlhAQABAAAAACH5BAEKAAEALAAAAAABAAEAAAICTAEAOw==' ); |
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$matches = array(); |
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$search = array(); |
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$replace = array(); |
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$content = preg_replace_callback( '~<noscript.+?</noscript>~s', 'self::noscripts_remove', $content ); |
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preg_match_all( '/<img[^>]*>/', $content, $matches ); |
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foreach ( $matches[0] as $img_html ) { |
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if ( ! ( preg_match( $skip_images_regex, $img_html ) ) ) { |
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$add_class = false; |
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if ( ! preg_match( '/src=[\'"]([^\'"]+)[\'"]/', $img_html ) && preg_match( '/srcset=[\'"]([^\'"]+)[\'"]/', $img_html ) ) { |
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$replace_html = preg_replace( '/<img(.*?)srcset=/i', '<img$1srcset="' . $placeholder_image . '" data-srcset=', $img_html ); |
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if ( preg_match( '/sizes=[\'"]([^\'"]+)[\'"]/', $img_html ) ) { |
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$replace_html = preg_replace( '/sizes=/i', 'data-sizes=', $replace_html ); |
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} else { |
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$replace_html = preg_replace( '/data-srcset=/i', 'data-sizes="auto" data-srcset=', $replace_html ); |
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} |
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$add_class = true; |
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} elseif ( preg_match( '/src=[\'"]([^\'"]+)[\'"]/', $img_html ) ) { |
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$replace_html = preg_replace( '/<img(.*?)src=/i', '<img$1src="' . $placeholder_image . '" data-src=', $img_html ); |
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if ( preg_match( '/srcset=[\'"]([^\'"]+)[\'"]/', $img_html ) ) { |
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if ( preg_match( '/sizes=[\'"]([^\'"]+)[\'"]/', $img_html ) ) { |
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$replace_html = preg_replace( '/srcset=/i', 'data-srcset=', $replace_html ); |
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$replace_html = preg_replace( '/sizes=/i', 'data-sizes=', $replace_html ); |
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} else { |
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$replace_html = preg_replace( '/srcset=/i', 'data-sizes="auto" data-srcset=', $replace_html ); |
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} |
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} |
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$add_class = true; |
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} |
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if ( $add_class ) { |
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$replace_html = self::add_class( $replace_html, 'lazyload' ); |
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$replace_html .= '<noscript>' . $img_html . '</noscript>'; |
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array_push( $search, $img_html ); |
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array_push( $replace, $replace_html ); |
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} |
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} |
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} |
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$content = str_replace( $search, $replace, $content ); |
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$content = preg_replace_callback( '~' . chr(20) . '([0-9]+)' . chr(20) . '~', 'self::noscripts_restore', $content ); |
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return $content; |
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} |
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static function noscripts_remove( $match ) { |
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self::$noscript_id++; |
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self::$noscripts[self::$noscript_id] = $match[0]; |
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return chr(20) . self::$noscript_id . chr(20); |
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} |
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static function noscripts_restore( $match ) { |
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return self::$noscripts[(int) $match[1]]; |
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} |
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static function add_class( $html_string = '', $new_class ) { |
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$pattern = '/class=[\'"]([^\'"]*)[\'"]/'; |
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if ( preg_match( $pattern, $html_string, $matches ) ) { |
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$defined_classes = explode( ' ', $matches[1] ); |
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if ( ! in_array( $new_class, $defined_classes ) ) { |
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$defined_classes[] = $new_class; |
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$html_string = str_replace( |
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$matches[0], |
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sprintf( 'class="%s"', implode( ' ', $defined_classes ) ), |
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$html_string |
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); |
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} |
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} else { |
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$html_string = preg_replace( '/(\<.+\s)/', sprintf( '$1class="%s" ', $new_class ), $html_string ); |
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} |
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return $html_string; |
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} |
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static function is_enabled() { |
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return self::$enabled; |
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} |
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static function kses_allowed_html( $allowedtags, $context ) { |
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$allowedtags['noscript'] = array(); |
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$allowedtags['img']['data-src'] = true; |
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$allowedtags['img']['data-srcset'] = true; |
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$allowedtags['img']['data-sizes'] = true; |
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return $allowedtags; |
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} |
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static function kses_allowed_protocols( $allowedprotocols ) { |
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$allowedprotocols[] = 'data'; |
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return $allowedprotocols; |
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} |
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} |
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add_action( 'init', array( 'LSX_LazyLoadImages', 'init' ) ); |
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Adding explicit visibility (
private
,protected
, orpublic
) is generally recommend to communicate to other developers how, and from where this method is intended to be used.