原型

_rotate_image_resource( $img,  $angle )

源文件

路径:wp-admin/includes/image-edit.php

<?php
...
		 * @param WP_Image_Editor $image     WP_Image_Editor instance.
		 * @param string          $mime_type Image mime type.
		 * @param int             $post_id   Post ID.
		 */
		$saved = apply_filters( 'wp_save_image_file', null, $filename, $image, $mime_type, $post_id );
		if ( null !== $saved )
			return $saved;
		switch ( $mime_type ) {
			case 'image/jpeg':
...
?>

其他

英文文档:https://developer.wordpress.org/reference/functions/_rotate_image_resource/