PHP 中 Orientation 属性判断上传图片是否需要旋转

<?php$image = imagecreatefromstring(file_get_contents($_FILES['image_upload']['tmp_name']));$exif = exif_read_data($_FILES['image_upload']['tmp_name']);if(!empty($exif['Orientation'])) { switch($exif['Orientation']) {  case 8:   $image = imagerotate($image,90,0);   break;  case 3:   $image = imagerotate($image,180,0);   break;  case 6:   $image = imagerotate($image,-90,0);   break; }}// $image now contains a resource with the image oriented correctly?>