wp_get_missing_image_subsizes( int $attachment_id ): array[]

Description

Compatibility

Present in every tracked release (6.7.7 to 7.1.0), and compiles on PHP 7.4 through 8.6-dev.

Parameters

$attachment_idint

The image attachment post ID.

Return value

array[]

Associative array of arrays of image sub-size information for missing image sizes, keyed by image size name.

Performance profile

How much work a call to wp_get_missing_image_subsizes() 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

Heavy

Reaches the database via get_post().

Scaling

Scales with input

The body loops, so the work grows with what you pass in.

Instructions

6–51

Executed per call on PHP 8.5, depending on the branch taken. The body compiles to 74.

Plugin surface

1 hook

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

Called by

2

2 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
• optionoption read or writeget_option()one call below wp_get_missing_image_subsizes()
• querycontent queryget_post()one call below wp_get_missing_image_subsizes()

Further down the call graph this can also reach 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 · 4 distinct outcomes

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

Hooks and filters fired · 1

One hook fires while wp_get_missing_image_subsizes() runs, in this order:

1. 1
   apply_filters( wp_get_missing_image_subsizes )filterline 146 (+59 into the body)

   Filters the array of missing image sub-sizes for an uploaded image.

Uses · 7

• wp_attachment_is_image()Determines whether an attachment is an image.
• wp_get_registered_image_subsizes()Returns a normalized list of all currently registered image sub-sizes.
• wp_get_attachment_metadata()Retrieves attachment metadata for attachment ID.
• wp_get_original_image_path()Retrieves the path to an uploaded image file.
• wp_getimagesize()Allows PHP's getimagesize() to be debuggable when necessary.
• image_resize_dimensions()Retrieves calculated resize dimensions for use in WP_Image_Editor.
• apply_filters()Calls the callback functions that have been added to a filter hook.

Used by · 2

• WP_REST_Attachments_Controller::prepare_item_for_response()Prepares a single attachment output for response.
• wp_update_image_subsizes()If any of the currently registered image sub-sizes are missing, create them and update the image meta data.

Source code

View on Trac ↗View on GitHub ↗

87function wp_get_missing_image_subsizes( $attachment_id ) {88	if ( ! wp_attachment_is_image( $attachment_id ) ) {89		return array();90	}91 92	$registered_sizes = wp_get_registered_image_subsizes();93	$image_meta       = wp_get_attachment_metadata( $attachment_id );94 95	// Meta error?96	if ( empty( $image_meta ) ) {97		return $registered_sizes;98	}99 100	// Use the originally uploaded image dimensions as full_width and full_height.101	if ( ! empty( $image_meta['original_image'] ) ) {102		$image_file = wp_get_original_image_path( $attachment_id );103		$imagesize  = wp_getimagesize( $image_file );104	}105 106	if ( ! empty( $imagesize ) ) {107		$full_width  = $imagesize[0];108		$full_height = $imagesize[1];109	} else {110		$full_width  = (int) $image_meta['width'];111		$full_height = (int) $image_meta['height'];112	}113 114	$possible_sizes = array();115 116	// Skip registered sizes that are too large for the uploaded image.117	foreach ( $registered_sizes as $size_name => $size_data ) {118		if ( image_resize_dimensions( $full_width, $full_height, $size_data['width'], $size_data['height'], $size_data['crop'] ) ) {119			$possible_sizes[ $size_name ] = $size_data;120		}121	}122 123	if ( empty( $image_meta['sizes'] ) ) {124		$image_meta['sizes'] = array();125	}126 127	/*128	 * Remove sizes that already exist. Only checks for matching "size names".129	 * It is possible that the dimensions for a particular size name have changed.130	 * For example the user has changed the values on the Settings -> Media screen.131	 * However we keep the old sub-sizes with the previous dimensions132	 * as the image may have been used in an older post.133	 */134	$missing_sizes = array_diff_key( $possible_sizes, $image_meta['sizes'] );135 136	/**137	 * Filters the array of missing image sub-sizes for an uploaded image.138	 *139	 * @since 5.3.0140	 *141	 * @param array[] $missing_sizes Associative array of arrays of image sub-size information for142	 *                               missing image sizes, keyed by image size name.143	 * @param array   $image_meta    The image meta data.144	 * @param int     $attachment_id The image attachment post ID.145	 */146	return apply_filters( 'wp_get_missing_image_subsizes', $missing_sizes, $image_meta, $attachment_id );147}

Changelog

Introduced in 5.3.0. Unchanged from 6.7.7 through 7.1.0.

1. 6.7.7
2. 6.8.8
3. 6.9.7
4. 7.0.4
5. 7.1.0

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

About this page

Parsed data

Generated from the wordpress-develop 7.1.0 tag, from src/wp-admin/includes/image.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.

Corrections

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