Measures the exact width and height of the costume. It can even measure fractional amounts (which are possible in vector based costumes), however it's only reliable for 4-5 decimals depending on the costume's size due to Scratch's limit in precision when going offscreen by a large amount. Credits to @--PaperPlanes_Test-- for the idea which I improved upon: https://scratch.mit.edu/projects/1240989408/ (their project also includes the general explanation for how this works)