Get an array of attributes for a WordPress image - similar to wp_get_attachment_image() but returns an array of values instead of the rendered HTML.

WPGetAttachmentImageAttributes.php

<?php
/**
 * Get WordPress Attachment Image Attributes.
 *
 * Similiar to running WordPress's wp_get_attachment_image() but
 * instead of getting back rendered HTML, we get back an array
 * where the key is the attribute name and the value is the attribute value.
 *
 * This is done by using the `wp_get_attachment_image_attributes` filter.
 *
 * e.g.
 *
 * [
 *     'width' => '1920'
 *     'height' => '1080'
 *     'src' => 'https://example.test/wp-content/uploads/2018/08/sal-1920x1080.jpg',
 *     'srcset' => 'https://example.test/wp-content/uploads/2018/08/sal-1920x1080.jpg 1920, https://example.test/wp-content/uploads/2018/08/sal-960x540.jpg 960w',
 *     'alt' => 'Photograph of Sal.',
 *     'sizes' => '(max-width: 1920px) 100vw, 1920px'
 *     'class' => 'attachment-fe-hero size-fe-hero'
 * ]
 *
 * @package salcode/wp-get-attachment-image-attributes
 */

declare(strict_types=1);

namespace salcode\WPGetAttachmentImageAttributes;

/**
 * Class: GetAttachmentImageAttributes
 */
class GetAttachmentImageAttributes {

	const FILTER_PRIORITY = 9999999;

	/**
	 * Image Attributes.
	 *
	 * Key/value array.
	 *
	 * @var string[]
	 */
	protected $attributes = [];

	/**
	 * The attachment_id for the image.
	 *
	 * @var int
	 */
	protected $attachment_id;

	/**
	 * WordPress Image Size.
	 *
	 * Either a WordPress image size string or an array of [ $width, $height ].
	 *
	 * @var string | array
	 */
	protected $size;

	/**
	 * The image should be treated as an icon.
	 *
	 * @var bool
	 */
	protected $icon = false;

	/**
	 * Attributes to be applied to the image.
	 *
	 * @var string | array
	 */
	protected $attr = '';

	public function __construct( int $attachment_id, $size = 'thumbnail', $icon = false, $attr = '' ) {
		$this->attachment_id = $attachment_id;
		$this->size          = $size;
		$this->icon          = $icon;
		$this->attr          = $attr;
	}

	public function get_attributes() {
		add_filter( 'wp_get_attachment_image_attributes', [ $this, 'capture_attributes' ], self::FILTER_PRIORITY );
		wp_get_attachment_image(
			$this->attachment_id,
			$this->size,
			$this->icon,
			$this->attr
		);
		remove_filter( 'wp_get_attachment_image_attributes', [ $this, 'capture_attributes' ], self::FILTER_PRIORITY );
		return ! empty( $this->attributes ) ? $this->attributes : [];
	}

	public function capture_attributes( $attributes ) {
		$this->attributes = $attributes;
		return $attributes;
	}

	static public function get( int $attachment_id, $size = 'thumbnail', $icon = false, $attr = '' ) {
		$obj = new static( $attachment_id, $size, $icon, $attr );
		return $obj->get_attributes();
	}
}