wp_get_loading_optimization_attributes( string $tag_name, array $attr, string $context ): array

Description

Compatibility

Present in every tracked release (6.7.10 to 7.1.3), and compiles on PHP 7.4 through 8.6-dev.

Parameters

$tag_namestring

The tag name.

$attrarray

Array of the attributes for the tag.

$contextstring

Context for the element for which the loading optimization attribute is requested.

Return value

array

Loading optimization attributes.

Performance profile

How much work a call to wp_get_loading_optimization_attributes() does, and what it touches: the algorithmic scaling, the Zend instruction count per call across PHP versions, the hooks it hands control to, and the core code that calls it. Measured from the compiled opcodes, not a stopwatch, so every number is identical on any machine running the same PHP version, and every function in core is ranked by cost.

Cost class

Trivial

Touches nothing outside its own arguments.

Scaling

Constant

No loop in the body: the same number of instructions runs whatever you pass in.

Instructions

37–127

Executed per call on PHP 8.5, depending on the branch taken. The body compiles to 209.

Plugin surface

4 hooks

Third-party callbacks on 'pre_wp_get_loading_optimization_attributes', 'wp_get_loading_optimization_attributes', 'wp_loading_optimization_force_header_contexts' run inside this call, and their cost is not bounded by anything here.

Called by

6

6 places in core call this, so the cost is paid more often than your own code shows.

What it touches

• hookthird-party callbacksapply_filters()called directly

Further down the call graph this can also reach query, option, cache, serialize and transient. Those are the worst case, several calls deep and usually down an error path, not what a normal call pays.

What one call costs · 241 distinct outcomes

One number would be a lie: the work depends on which branch runs. These are every distinct cost wp_get_loading_optimization_attributes() can have, taken from its control-flow graph on PHP 8.5.

This body has more branch combinations than are worth enumerating, so the table covers the outcomes found first rather than every one that exists.

Hooks and filters fired · 8

8 hooks fire while wp_get_loading_optimization_attributes() runs, in this order:

1. 1
   apply_filters( pre_wp_get_loading_optimization_attributes )filterline 5942 (+16 into the body)

   Filters whether to short-circuit loading optimization attributes.

2. 2
   apply_filters( wp_get_loading_optimization_attributes )filterline 5956 (+30 into the body)

   Filters the loading optimization attributes.

3. 3
   apply_filters( wp_get_loading_optimization_attributes )filterline 5962 (+36 into the body)

   Filters the loading optimization attributes.

4. 4
   apply_filters( wp_get_loading_optimization_attributes )filterline 5978 (+52 into the body)

   Filters the loading optimization attributes.

5. 5
   apply_filters( wp_get_loading_optimization_attributes )filterline 5997 (+71 into the body)

   Filters the loading optimization attributes.

6. 6
   apply_filters( wp_loading_optimization_force_header_contexts )filterline 6062 (+136 into the body)

   Filters the header-specific contexts.

7. 7
   apply_filters( wp_min_priority_img_pixels )filterline 6125 (+199 into the body)

   Filters the minimum square-pixels threshold for an image to be eligible as the high-priority image.

8. 8
   apply_filters( wp_get_loading_optimization_attributes )filterline 6142 (+216 into the body)

   Filters the loading optimization attributes.

Uses · 12

• apply_filters()Calls the callback functions that have been added to a filter hook.
• doing_filter()Returns whether or not a filter hook is currently being processed.
• _doing_it_wrong()Marks something as being incorrectly called.
• __()Retrieves the translation of $text.
• is_admin()Determines whether the current request is for an administrative interface page.
• in_the_loop()Determines whether the caller is in the Loop.
• is_main_query()Determines whether the query is the main query.
• wp_increase_content_media_count()Increases an internal content media count variable.
• wp_omit_loading_attr_threshold()Gets the threshold for how many of the first content media elements to not lazy-load.
• did_action()Retrieves the number of times an action has been fired during the current request.
• wp_maybe_add_fetchpriority_high_attr()Determines whether to add `fetchpriority='high'` to loading attributes.
• wp_lazy_loading_enabled()Determines whether to add the `loading` attribute to the specified tag in the specified context.

Used by · 6

• WP_Widget_Media_Image::render_media()Render the media on the frontend.
• get_avatar()Retrieves the avatar `` tag for a user, email address, MD5 hash, comment, or post.
• get_header_image_tag()Creates image tag markup for a custom header image.
• wp_get_attachment_image()Gets an HTML img element representing an image attachment.
• wp_iframe_tag_add_loading_attr()Adds `loading` attribute to an `iframe` HTML tag.
• wp_img_tag_add_loading_optimization_attrs()Adds optimization attributes to an `img` HTML tag.

Source code

View on Trac ↗View on GitHub ↗

5926function wp_get_loading_optimization_attributes( $tag_name, $attr, $context ) {5927	global $wp_query;5928 5929	/**5930	 * Filters whether to short-circuit loading optimization attributes.5931	 *5932	 * Returning an array from the filter will effectively short-circuit the loading of optimization attributes,5933	 * returning that value instead.5934	 *5935	 * @since 6.4.05936	 *5937	 * @param array|false $loading_attrs False by default, or array of loading optimization attributes to short-circuit.5938	 * @param string      $tag_name      The tag name.5939	 * @param array       $attr          Array of the attributes for the tag.5940	 * @param string      $context       Context for the element for which the loading optimization attribute is requested.5941	 */5942	$loading_attrs = apply_filters( 'pre_wp_get_loading_optimization_attributes', false, $tag_name, $attr, $context );5943 5944	if ( is_array( $loading_attrs ) ) {5945		return $loading_attrs;5946	}5947 5948	$loading_attrs = array();5949 5950	/*5951	 * Skip lazy-loading for the overall block template, as it is handled more granularly.5952	 * The skip is also applicable for `fetchpriority`.5953	 */5954	if ( 'template' === $context ) {5955		/** This filter is documented in wp-includes/media.php */5956		return apply_filters( 'wp_get_loading_optimization_attributes', $loading_attrs, $tag_name, $attr, $context );5957	}5958 5959	// For now this function only supports images and iframes.5960	if ( 'img' !== $tag_name && 'iframe' !== $tag_name ) {5961		/** This filter is documented in wp-includes/media.php */5962		return apply_filters( 'wp_get_loading_optimization_attributes', $loading_attrs, $tag_name, $attr, $context );5963	}5964 5965	/*5966	 * Skip programmatically created images within content blobs as they need to be handled together with the other5967	 * images within the post content or widget content.5968	 * Without this clause, they would already be considered within their own context which skews the image count and5969	 * can result in the first post content image being lazy-loaded or an image further down the page being marked as a5970	 * high priority.5971	 */5972	if (5973		'the_content' !== $context && doing_filter( 'the_content' ) ||5974		'widget_text_content' !== $context && doing_filter( 'widget_text_content' ) ||5975		'widget_block_content' !== $context && doing_filter( 'widget_block_content' )5976	) {5977		/** This filter is documented in wp-includes/media.php */5978		return apply_filters( 'wp_get_loading_optimization_attributes', $loading_attrs, $tag_name, $attr, $context );5979 5980	}5981 5982	/*5983	 * Add `decoding` with a value of "async" for every image unless it has a5984	 * conflicting `decoding` attribute already present.5985	 */5986	if ( 'img' === $tag_name ) {5987		if ( isset( $attr['decoding'] ) ) {5988			$loading_attrs['decoding'] = $attr['decoding'];5989		} else {5990			$loading_attrs['decoding'] = 'async';5991		}5992	}5993 5994	// For any resources, width and height must be provided, to avoid layout shifts.5995	if ( ! isset( $attr['width'], $attr['height'] ) ) {5996		/** This filter is documented in wp-includes/media.php */5997		return apply_filters( 'wp_get_loading_optimization_attributes', $loading_attrs, $tag_name, $attr, $context );5998	}5999 6000	/*6001	 * The key function logic starts here.6002	 */6003	$maybe_in_viewport    = null;6004	$increase_count       = false;6005	$maybe_increase_count = false;

Changelog

Introduced in 6.3.0. Unchanged from 6.7.10 through 7.1.3.

1. 6.7.10
2. 6.8.11
3. 6.9.10
4. 7.0.7
5. 7.1.3

Signature, return type and hooks compared across 5 parsed releases.

About this page

Parsed data

Generated from the wordpress-develop 6.7.10 tag, from src/wp-includes/media.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.

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