wp_calculate_image_sizes( string|int[] $size, string|null $image_src = null, array|null $image_meta = null, int $attachment_id ): string|false

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Creates a ‘sizes’ attribute value for an image.

Parameters

$sizestring|int[]required
Image size. Accepts any registered image size name, or an array of width and height values in pixels (in that order).
$image_srcstring|nulloptional
The URL to the image file.

Default:null

$image_metaarray|nulloptional
The image meta data as returned by ‘wp_get_attachment_metadata() ‘.

Default:null

$attachment_idintoptional
Image attachment ID. Either $image_meta or $attachment_id is needed when using the image size name as argument for $size. Default 0.

Return

string|false A valid source size value for use in a 'sizes' attribute or false.

Source

 * @since 4.4.0
 *
 * @param string|int[] $size          Image size. Accepts any registered image size name, or an array of
 *                                    width and height values in pixels (in that order).
 * @param string|null  $image_src     Optional. The URL to the image file. Default null.
 * @param array|null   $image_meta    Optional. The image meta data as returned by 'wp_get_attachment_metadata()'.
 *                                    Default null.
 * @param int          $attachment_id Optional. Image attachment ID. Either `$image_meta` or `$attachment_id`
 *                                    is needed when using the image size name as argument for `$size`. Default 0.
 * @return string|false A valid source size value for use in a 'sizes' attribute or false.
 */
function wp_calculate_image_sizes( $size, $image_src = null, $image_meta = null, $attachment_id = 0 ) {
	$width = 0;

	if ( is_array( $size ) ) {
		$width = absint( $size[0] );
	} elseif ( is_string( $size ) ) {
		if ( ! $image_meta && $attachment_id ) {
			$image_meta = wp_get_attachment_metadata( $attachment_id );
		}

		if ( is_array( $image_meta ) ) {
			$size_array = _wp_get_image_size_from_meta( $size, $image_meta );
			if ( $size_array ) {
				$width = absint( $size_array[0] );
			}
		}
	}

	if ( ! $width ) {
		return false;
	}

	// Setup the default 'sizes' attribute.
	$sizes = sprintf( '(max-width: %1$dpx) 100vw, %1$dpx', $width );

	/**
	 * Filters the output of 'wp_calculate_image_sizes()'.
	 *

Changelog

VersionDescription
4.4.0Introduced.

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