performance-lab / modules / images / fetchpriority / hooks.php

hooks.php in Performance Lab 2.1.0, at modules/images/fetchpriority/hooks.php

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1	<?php
2	/**
3	* Hook callbacks used for Fetchpriority.
4	*
5	* @package performance-lab
6	* @since 2.1.0
7	*/
8
9	/**
10	* Filters an image tag in content to add the fetchpriority attribute if it is not lazy-loaded.
11	*
12	* @since 1.8.0
13	*
14	* @param string $filtered_image The image tag to filter.
15	* @param string $context The context of the image.
16	* @return string The filtered image tag.
17	*/
18	function fetchpriority_img_tag_add_attr( $filtered_image, $context ) {
19
20	if ( 'the_content' !== $context && 'the_post_thumbnail' !== $context ) {
21	return $filtered_image;
22	}
23
24	// Fetchpriority relies on lazy loading logic.
25	if ( ! wp_lazy_loading_enabled( 'img', $context ) ) {
26	return $filtered_image;
27	}
28
29	if ( ! empty( $filtered_image ) && strpos( $filtered_image, 'loading="lazy"' ) === false && strpos( $filtered_image, 'fetchpriority=' ) === false ) {
30	$filtered_image = str_replace( '<img ', '<img fetchpriority="high" ', $filtered_image );
31	remove_filter( 'wp_content_img_tag', 'fetchpriority_img_tag_add_attr' );
32	remove_filter( 'post_thumbnail_html', 'fetchpriority_filter_post_thumbnail_html' );
33	}
34
35	return $filtered_image;
36	}
37	add_filter( 'wp_content_img_tag', 'fetchpriority_img_tag_add_attr', 10, 2 );
38
39	/**
40	* Filters the post thumbnail HTML to conditionally add the fetchpriority attribute.
41	*
42	* @since 1.8.0
43	*
44	* @param string $html The post thumbnail HTML to filter.
45	* @return string The filtered post thumbnail HTML.
46	*/
47	function fetchpriority_filter_post_thumbnail_html( $html ) {
48	$html = fetchpriority_img_tag_add_attr( $html, 'the_post_thumbnail' );
49
50	return $html;
51	}
52	add_filter( 'post_thumbnail_html', 'fetchpriority_filter_post_thumbnail_html' );
53