stream_preview_image( int $post_id ): bool

Compatibility

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

Parameters

$post_idint

Attachment post ID.

Return value

bool

True on success, false on failure.

Performance profile

How much work a call to stream_preview_image() 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

Constant

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

Instructions

20–70

Executed per call on PHP 8.5, depending on the branch taken. The body compiles to 73.

Plugin surface

None

Nothing here hands control to plugin code.

Called by

1

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

What it touches

• querycontent queryget_post()called directly
• serializeserialisationjson_decode()called directly
• hookthird-party callbacksapply_filters()one call below stream_preview_image()

Further down the call graph this can also reach cache, option 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 · 9 distinct outcomes

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

Uses · 9

• get_post()Retrieves post data given a post ID or post object.
• wp_raise_memory_limit()Attempts to raise the PHP memory limit for memory intensive processes.
• wp_get_image_editor()Returns a WP_Image_Editor instance and loads file into it.
• _load_image_to_edit_path()Retrieves the path or URL of an attachment's attached file.
• is_wp_error()Checks whether the given variable is a WordPress Error.
• wp_unslash()Removes slashes from a string or recursively removes slashes from strings within an array.
• image_edit_apply_changes()Performs group of changes on Editor specified.
• _image_get_preview_ratio()Image preview ratio. Internal use only.
• wp_stream_image()Streams image in WP_Image_Editor to browser.

Used by · 1

• wp_ajax_imgedit_preview()Handles image editor previews via AJAX.

Source code

View on Trac ↗View on GitHub ↗

775function stream_preview_image( $post_id ) {776	$post = get_post( $post_id );777 778	wp_raise_memory_limit( 'admin' );779 780	$img = wp_get_image_editor( _load_image_to_edit_path( $post_id ) );781 782	if ( is_wp_error( $img ) ) {783		return false;784	}785 786	$changes = ! empty( $_REQUEST['history'] ) ? json_decode( wp_unslash( $_REQUEST['history'] ) ) : null;787	if ( $changes ) {788		$img = image_edit_apply_changes( $img, $changes );789	}790 791	// Scale the image.792	$size = $img->get_size();793	$w    = $size['width'];794	$h    = $size['height'];795 796	$ratio = _image_get_preview_ratio( $w, $h );797	$w2    = max( 1, $w * $ratio );798	$h2    = max( 1, $h * $ratio );799 800	if ( is_wp_error( $img->resize( $w2, $h2 ) ) ) {801		return false;802	}803 804	return wp_stream_image( $img, $post->post_mime_type, $post_id );805}

Changelog

Introduced in 2.9.0. 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-edit.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.

Corrections

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