_mce_set_direction() WordPress Function

function _mce_set_direction( $mce_init ) {
	if ( is_rtl() ) {
		$mce_init['directionality'] = 'rtl';
		$mce_init['rtl_ui']         = true;

		if ( ! empty( $mce_init['plugins'] ) && strpos( $mce_init['plugins'], 'directionality' ) === false ) {
			$mce_init['plugins'] .= ',directionality';
		}

		if ( ! empty( $mce_init['toolbar1'] ) && ! preg_match( '/\bltr\b/', $mce_init['toolbar1'] ) ) {
			$mce_init['toolbar1'] .= ',ltr';
		}
	}

	return $mce_init;
}