1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
|
<?php
class Jetpack_Lazy_Images {
private static $__instance = null;
/**
* Singleton implementation
*
* @return object
*/
public static function instance() {
if ( is_null( self::$__instance ) ) {
self::$__instance = new Jetpack_Lazy_Images();
}
return self::$__instance;
}
/**
* Registers actions
*/
private function __construct() {
if ( is_admin() ) {
return;
}
/**
* Whether the lazy-images module should load.
*
* This filter is not prefixed with jetpack_ to provide a smoother migration
* process from the WordPress Lazy Load plugin.
*
* @module lazy-images
*
* @since 5.6.0
*
* @param bool true Whether lazy image loading should occur.
*/
if ( ! apply_filters( 'lazyload_is_enabled', true ) ) {
return;
}
add_action( 'wp_head', array( $this, 'setup_filters' ), 9999 ); // we don't really want to modify anything in <head> since it's mostly all metadata
add_action( 'wp_enqueue_scripts', array( $this, 'enqueue_assets' ) );
// Do not lazy load avatar in admin bar
add_action( 'admin_bar_menu', array( $this, 'remove_filters' ), 0 );
}
public function setup_filters() {
add_filter( 'the_content', array( $this, 'add_image_placeholders' ), 99 ); // run this later, so other content filters have run, including image_add_wh on WP.com
add_filter( 'post_thumbnail_html', array( $this, 'add_image_placeholders' ), 11 );
add_filter( 'get_avatar', array( $this, 'add_image_placeholders' ), 11 );
}
public function remove_filters() {
remove_filter( 'the_content', array( $this, 'add_image_placeholders' ), 99 );
remove_filter( 'post_thumbnail_html', array( $this, 'add_image_placeholders' ), 11 );
remove_filter( 'get_avatar', array( $this, 'add_image_placeholders' ), 11 );
}
public function add_image_placeholders( $content ) {
// Don't lazyload for feeds, previews
if ( is_feed() || is_preview() ) {
return $content;
}
// Don't lazy-load if the content has already been run through previously
if ( false !== strpos( $content, 'data-lazy-src' ) ) {
return $content;
}
// Don't lazyload for amp-wp content
if ( function_exists( 'is_amp_endpoint' ) && is_amp_endpoint() ) {
return $content;
}
// This is a pretty simple regex, but it works
$content = preg_replace_callback( '#<(img)([^>]+?)(>(.*?)</\\1>|[\/]?>)#si', array( __CLASS__, 'process_image' ), $content );
return $content;
}
static function process_image( $matches ) {
$old_attributes_str = $matches[2];
$old_attributes_kses_hair = wp_kses_hair( $old_attributes_str, wp_allowed_protocols() );
if ( empty( $old_attributes_kses_hair['src'] ) ) {
return $matches[0];
}
$old_attributes = self::flatten_kses_hair_data( $old_attributes_kses_hair );
$new_attributes = $old_attributes;
// Set placeholder and lazy-src
$new_attributes['src'] = self::get_placeholder_image();
$new_attributes['data-lazy-src'] = $old_attributes['src'];
// Handle `srcset`
if ( ! empty( $new_attributes['srcset'] ) ) {
$new_attributes['data-lazy-srcset'] = $old_attributes['srcset'];
unset( $new_attributes['srcset'] );
}
// Handle `sizes`
if ( ! empty( $new_attributes['sizes'] ) ) {
$new_attributes['data-lazy-sizes'] = $old_attributes['sizes'];
unset( $new_attributes['sizes'] );
}
/**
* Allow plugins and themes to override the attributes on the image before the content is updated.
*
* One potential use of this filter is for themes that set `height:auto` on the `img` tag.
* With this filter, the theme could get the width and height attributes from the
* $new_attributes array and then add a style tag that sets those values as well, which could
* minimize reflow as images load.
*
* @module lazy-images
*
* @since 5.6.0
*
* @param array An array containing the attributes for the image, where the key is the attribute name
* and the value is the attribute value.
*/
$new_attributes = apply_filters( 'jetpack_lazy_images_new_attributes', $new_attributes );
$new_attributes_str = self::build_attributes_string( $new_attributes );
return sprintf( '<img %1$s><noscript>%2$s</noscript>', $new_attributes_str, $matches[0] );
}
private static function get_placeholder_image() {
/**
* Allows plugins and themes to modify the placeholder image.
*
* This filter is not prefixed with jetpack_ to provide a smoother migration
* process from the WordPress Lazy Load plugin.
*
* @module lazy-images
*
* @since 5.6.0
*
* @param string The URL to the placeholder image
*/
return apply_filters(
'lazyload_images_placeholder_image',
plugins_url( 'modules/lazy-images/images/1x1.trans.gif', JETPACK__PLUGIN_FILE )
);
}
private static function flatten_kses_hair_data( $attributes ) {
$flattened_attributes = array();
foreach ( $attributes as $name => $attribute ) {
$flattened_attributes[ $name ] = $attribute['value'];
}
return $flattened_attributes;
}
private static function build_attributes_string( $attributes ) {
$string = array();
foreach ( $attributes as $name => $value ) {
if ( '' === $value ) {
$string[] = sprintf( '%s', $name );
} else {
$string[] = sprintf( '%s="%s"', $name, esc_attr( $value ) );
}
}
return implode( ' ', $string );
}
public function enqueue_assets() {
wp_enqueue_script(
'jetpack-lazy-images',
plugins_url( 'modules/lazy-images/js/lazy-images.js', JETPACK__PLUGIN_FILE ),
array( 'jquery' ),
JETPACK__VERSION,
true
);
}
}
|
GitWeb