Matthew Flatt wrote: > A monocrhome bitmap doesn't have an alpha channel, but it you ask for > its pixels in `just-alpha?' mode, then while pixels generate a 0 alpha > and black pixels generate a 255 alpha. >
Thanks Matthew. What confused me was that for: (send a-dc set-alpha opacity) opacity is a value between 0 and 1 (not a value between 0 and 255) and I didn't realize this method acts as a multiplier of each pixels alpha channel and doesn't set the value of the alpha channel directly. So I incorrectly assumed each pixels alpha channel has a value between 0 and 1 not between 0 and 255. Cheers, Harry Spier ____________________ Racket Users list: http://lists.racket-lang.org/users
