Is the emission of semen due to the rubbing of trousers against the penis, without intending arousal or pleasure, after a period of repentance from masturbation, considered to necessitate ghusl, and what is its ruling?

You must direct your mind and activity towards learning a beneficial knowledge or a useful skill. Thinking about engaging in sexual activity with someone who is unlawful is harmful and a waste of effort and thought. It may lead to committing indecency or masturbation. Masturbation includes causing semen to exit by hand or through imagination. Adhere to what we have advised you and abandon this thinking and imagination. Be keen on what benefits you, and ghusl (definition) (ritual bath) is obligatory upon the emission of semen.