[plt-scheme] determining sizes of pict

Given:


(require (lib "mrpict.ss" "texpict"))

(define dc (new bitmap-dc% (bitmap #f)))

(dc-for-text-size dc)

(define p (text "Hello World" null 24))


How would we determine the height, width, ascent, descent of the  
#<struct:pict> ?

- dr