Of Art and Literature

In Persepolis, there were many instances where the main character or other girls were asked to ‘correct’ their Hijab. Countries such as Iran and Saudi Arabia also specify a legal code for the Hijab. This made me think of what the hijab is judged against or how it is decided. Is there a Hijab-O-Meter that decides these things? Should anyone decide these things? What would the variations on it look like? Even after an approved state of the Hijab, are there degrees even after that to measure who’s hijab is better?