wp_enqueue_img_auto_sizes_contain_css_fix()
- Since
- 6.9.0
- Source
wp-includes/media.php:2196
sizes=auto.Description
This rule overrides the similar rule in the default user agent stylesheet, to avoid images that use e.g.width: auto or width: fit-content to appear smaller.
Compatibility
- WordPress
- since 6.9.0
- PHP
- 7.4–8.6-dev
- 6.7.7
- 6.8.8
- 6.9.7
- 7.0.4
- 7.1.0
Present in 3 of the 5 tracked releases, added in 6.9.0, and compiles on PHP 7.4 through 8.6-dev.
Performance profile
How much work a call to wp_enqueue_img_auto_sizes_contain_css_fix() 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
- Scaling
- Constant
- Instructions
- 8–36
- Plugin surface
- 1 hook
- Called by
- 0
Touches nothing outside its own arguments.
No loop in the body: the same number of instructions runs whatever you pass in.
Executed per call on PHP 8.5, depending on the branch taken. The body compiles to 38.
Third-party callbacks on 'wp_img_tag_add_auto_sizes' run inside this call, and their cost is not bounded by anything here.
Nothing in core calls this; the cost is only what you spend yourself.
What it touches
- hookthird-party callbacks
apply_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 · 3 distinct outcomes
One number would be a lie: the work depends on which branch runs. These are every distinct cost wp_enqueue_img_auto_sizes_contain_css_fix() can have, taken from its control-flow graph on PHP 8.5.
| When | Instructions | Calls it makes |
|---|---|---|
$priority === false | 8 | has_action() |
$priority !== false | 19 | has_action(), remove_action(), apply_filters() |
$priority !== false | 36 | has_action(), remove_action(), apply_filters(), wp_register_style(), wp_add_inline_style(), wp_styles(), array_unshift() |
Across PHP versions
Compiles the same on PHP 7.4, 8.1, 8.2, 8.3, 8.4, 8.5 and 8.6-dev: 38 instructions, 8–36 executed per call, 2 branches. The work does not change between versions.
An instruction is not a fixed amount of time, so a matching count is not necessarily the same speed; what it rules out is a difference in the work itself.
Hooks and filters fired · 1
One hook fires while wp_enqueue_img_auto_sizes_contain_css_fix() runs, in this order:
- apply_filters( wp_img_tag_add_auto_sizes )filterline 2205 (+9 into the body)
Filters whether auto-sizes for lazy loaded images is enabled.
Uses · 6
- has_action()Checks if any action has been registered for a hook.
- remove_action()Removes a callback function from an action hook.
- apply_filters()Calls the callback functions that have been added to a filter hook.
- wp_register_style()Registers a CSS stylesheet.
- wp_add_inline_style()Adds extra CSS styles to a registered stylesheet.
- wp_styles()Initializes $wp_styles if it has not been set.
Source code
function wp_enqueue_img_auto_sizes_contain_css_fix(): void { // Back-compat for plugins that disable functionality by unhooking this action. $priority = has_action( 'wp_head', 'wp_print_auto_sizes_contain_css_fix' ); if ( false === $priority ) { return; } remove_action( 'wp_head', 'wp_print_auto_sizes_contain_css_fix', $priority ); /** This filter is documented in wp-includes/media.php */ $add_auto_sizes = apply_filters( 'wp_img_tag_add_auto_sizes', true ); if ( ! $add_auto_sizes ) { return; } $handle = 'wp-img-auto-sizes-contain'; wp_register_style( $handle, false ); wp_add_inline_style( $handle, 'img:is([sizes=auto i],[sizes^="auto," i]){contain-intrinsic-size:3000px 1500px}' ); // Make sure inline style is printed first since it was previously printed at wp_head priority 1 and this preserves the CSS cascade. array_unshift( wp_styles()->queue, $handle );}Changelog
Introduced in 6.9.0. Unchanged from 6.9.7 through 7.1.0.
Signature, return type and hooks compared across 3 parsed releases.
About this page
- Parsed data
- Generated from the wordpress-develop 7.1.0 tag, from
src/wp-includes/media.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it. - Corrections
- Something wrong on this page? Report it and it gets fixed in the next regeneration.