On Fri, 16 Sep 2016 06:04:09 -0500, Robby Findler <ro...@eecs.northwestern.edu> wrote:
>You could draw into a bitmap and then have on-paint draw that bitmap, too. > >Robby Yes. "Double buffering" with an off-screen bitmap is the best way to minimize redrawing. However, it also should be pointed out that the DC has a clipping region. When a region is set, drawing will occur only within the region's boundaries - any pixels outside the region will be preserved. https://docs.racket-lang.org/draw/region_.html?q=region https://docs.racket-lang.org/draw/dc___.html?q=region#%28meth._%28%28%28lib._racket%2Fdraw..rkt%29._dc~3c~25~3e%29._set-clipping-region%29%29 https://docs.racket-lang.org/gui/canvas___.html?q=canvas#%28meth._%28%28%28lib._mred%2Fmain..rkt%29._canvas~3c~25~3e%29._get-dc%29%29 George -- You received this message because you are subscribed to the Google Groups "Racket Users" group. To unsubscribe from this group and stop receiving emails from it, send an email to racket-users+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
