public static function getTransformation($orientation)
    {
        $transformation = '';
        if (
            (isset($GLOBALS['TYPO3_CONF_VARS']['GFX']['processor']) && $GLOBALS['TYPO3_CONF_VARS']['GFX']['processor'] === 'ImageMagick')
            ||
            (isset($GLOBALS['TYPO3_CONF_VARS']['GFX']['im_version_5']) && $GLOBALS['TYPO3_CONF_VARS']['GFX']['im_version_5'] !== 'gm')
        ) {
            // ImageMagick
            if ($orientation >= 2 && $orientation <= 8) {
                $transformation = '-auto-orient';
            }
        } else {
            // GraphicsMagick
            switch ($orientation) {
                case 2: // horizontal flip
                    $transformation = '-flip horizontal';
                    break;
                case 3: // 180°
                    $transformation = '-rotate 180';
                    break;
                case 4: // vertical flip
                    $transformation = '-flip vertical';
                    break;
                case 5: // vertical flip + 90 rotate right
                    $transformation = '-transpose';
                    break;
                case 6: // 90° rotate right
                    $transformation = '-rotate 90';
                    break;
                case 7: // horizontal flip + 90 rotate right
                    $transformation = '-transverse';
                    break;
                case 8: // 90° rotate left
                    $transformation = '-rotate 270';
                    break;
            }
        }
        return $transformation;
    }