WP_Image_Editor::set_quality( int $quality = null, array $dims = array() ): true|WP_Error

Compatibility

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

Parameters

$qualityintoptional

Compression Quality. Range: [1,100]Default: null

$dimsarrayoptional

Image dimensions array with 'width' and 'height' keys.Default: array()

Return value

true|WP_Error

True if set successfully; WP_Error on failure.

Performance profile

How much work a call to WP_Image_Editor::set_quality() 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

21–51

Executed per call on PHP 8.5, depending on the branch taken. The body compiles to 56.

Plugin surface

2 hooks

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

Called by

4

4 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 · 6 distinct outcomes

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

Hooks and filters fired · 2

2 hooks fire while WP_Image_Editor::set_quality() runs, in this order:

1. 1
   apply_filters( wp_editor_set_quality )filterline 269 (+27 into the body)

   Filters the default image compression quality setting.

2. 2
   apply_filters( jpeg_quality )filterline 288 (+46 into the body)

   Filters the JPEG compression quality for backward-compatibility.

Uses · 4

• apply_filters()Calls the callback functions that have been added to a filter hook.
• __()Retrieves the translation of $text.
• WP_Image_Editor::get_default_quality()Returns the default compression quality setting for the mime type.
• WP_Error::__construct()Initializes the error.

Used by · 4

• WP_Image_Editor::get_output_format()Returns preferred mime-type and extension based on provided file's extension and mime, or current file's extension and mime.
• WP_Image_Editor::get_quality()Gets the Image Compression quality on a 1-100% scale.
• WP_Image_Editor_GD::set_quality()Sets Image Compression quality on a 1-100% scale. Handles WebP lossless images.
• WP_Image_Editor_Imagick::set_quality()Sets Image Compression quality on a 1-100% scale.

Source code

View on Trac ↗View on GitHub ↗

242	public function set_quality( $quality = null, $dims = array() ) {243		// Use the output mime type if present. If not, fall back to the input/initial mime type.244		$mime_type = ! empty( $this->output_mime_type ) ? $this->output_mime_type : $this->mime_type;245		// Get the default quality setting for the mime type.246		$default_quality = $this->get_default_quality( $mime_type );247 248		if ( null === $quality ) {249			/**250			 * Filters the default image compression quality setting.251			 *252			 * Applies only during initial editor instantiation, or when set_quality() is run253			 * manually without the `$quality` argument.254			 *255			 * The WP_Image_Editor::set_quality() method has priority over the filter.256			 *257			 * @since 3.5.0258			 * @since 6.8.0 Added the size parameter.259			 *260			 * @param int    $quality   Quality level between 1 (low) and 100 (high).261			 * @param string $mime_type Image mime type.262			 * @param array $size {263			 *     Dimensions of the image.264			 *265			 *     @type int $width  The image width.266			 *     @type int $height The image height.267			 * }268			 */269			$quality = apply_filters( 'wp_editor_set_quality', $default_quality, $mime_type, $dims ? $dims : $this->size );270 271			if ( 'image/jpeg' === $mime_type ) {272				/**273				 * Filters the JPEG compression quality for backward-compatibility.274				 *275				 * Applies only during initial editor instantiation, or when set_quality() is run276				 * manually without the `$quality` argument.277				 *278				 * The WP_Image_Editor::set_quality() method has priority over the filter.279				 *280				 * The filter is evaluated under two contexts: 'image_resize', and 'edit_image',281				 * (when a JPEG image is saved to file).282				 *283				 * @since 2.5.0284				 *285				 * @param int    $quality Quality level between 0 (low) and 100 (high) of the JPEG.286				 * @param string $context Context of the filter.287				 */288				$quality = apply_filters( 'jpeg_quality', $quality, 'image_resize' );289			}290 291			if ( $quality < 0 || $quality > 100 ) {292				$quality = $default_quality;293			}294		}295 296		// Allow 0, but squash to 1 due to identical images in GD, and for backward compatibility.297		if ( 0 === $quality ) {298			$quality = 1;299		}300 301		if ( ( $quality >= 1 ) && ( $quality <= 100 ) ) {302			$this->quality = $quality;303			return true;304		} else {305			return new WP_Error( 'invalid_image_quality', __( 'Attempted to set image quality outside of the range [1,100].' ) );306		}307	}

Changelog

Introduced in 3.5.0. One change between 6.7.7 and 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 6.9.7 tag, from src/wp-includes/class-wp-image-editor.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.

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