On Tue, Sep 13, 2011 at 5:53 AM, Stephen Bloch <bl...@adelphi.edu> wrote: > > On Sep 13, 2011, at 4:03 AM, Robby Findler wrote: > >> That would be a bug (if an entire width*height bitmap were being >> re-created and thrown away each time and the program was just creating >> a few circles instead of creating a bitmap of that size). >> ... >> A 2htdp/image is just a tree where overlays (and things like that) are >> interior nodes and leaf nodes are things like circles. > > Right, but at some point it gets rendered to the (presumably pixel-map) > graphics device. IIRC, this is done by a function named "render" that > returns a bitmap, and the resulting bitmap is then drawn on the screen, which > would indeed mean that an entire width*height bitmap was being re-created and > thrown away each time.
It isn't "thrown away" in the sense that a new one is allocated and an old one is garbage collected. But yes, eventually the same set of pixels have to be computed and drawn. Robby _________________________________________________ For list-related administrative tasks: http://lists.racket-lang.org/listinfo/users
