[racket-dev] Universe double buffering
Why doesn't 2htdp/universe use double-buffering? --- nadeem _ For list-related administrative tasks: http://lists.racket-lang.org/listinfo/dev
Re: [racket-dev] Universe double buffering
Why do you think it doesn't? On Sep 2, 2010, at 8:52 AM, Nadeem Abdul Hamid wrote: > Why doesn't 2htdp/universe use double-buffering? > > --- nadeem > _ > For list-related administrative tasks: > http://lists.racket-lang.org/listinfo/dev _ For list-related administrative tasks: http://lists.racket-lang.org/listinfo/dev
Re: [racket-dev] Universe double buffering
> Why do you think it doesn't? (I'm assuming you mean: "What makes me think that it is not double-buffering?") ... I have a list of 15 thumbnail images of people and a function that places pairs of them side by side, using above/beside to create a 133 x 581 image. i.e. choose-and-show-pairs : (listof image) -> image Now, when I do: (big-bang PIC-LIST (on-draw choose-and-show-pairs)) I see each individual image getting laid out, one by one, rather excrutiatingly slowly. The choose-and-show-pairs actually randomizes the pairing up, and so if I move the mouse over the canvas, apparently the redraw handler is called, so I see a new set of pairs getting laid out, very slowly. I would have expected a double-buffered implementation to lay out the images in memory on some bitmap buffer and then quickly transfer the bitmap buffer to the canvas, so you don't actually witness the effect of all the above/beside operations happening. > > > > > On Sep 2, 2010, at 8:52 AM, Nadeem Abdul Hamid wrote: > >> Why doesn't 2htdp/universe use double-buffering? >> >> --- nadeem >> _ >> For list-related administrative tasks: >> http://lists.racket-lang.org/listinfo/dev > > -- Nadeem Abdul Hamid Associate Professor, Computer Science Berry College PO Box 5014 2277 Martha Berry Hwy NW Mount Berry, GA 30149-5014 (706) 368-5632 http://cs.berry.edu/~nhamid/ _ For list-related administrative tasks: http://lists.racket-lang.org/listinfo/dev
Re: [racket-dev] Universe double buffering
It sounds like there is also a performance problem there too. If you don't mind supplying a program for us to play with to see if we can do better, that would be helpful (but no promises ). Robby On Thu, Sep 2, 2010 at 8:15 AM, Nadeem Abdul Hamid wrote: >> Why do you think it doesn't? > > (I'm assuming you mean: "What makes me think that it is not > double-buffering?") ... > > I have a list of 15 thumbnail images of people and a function that > places pairs of them side by side, using above/beside to create a 133 > x 581 image. i.e. > choose-and-show-pairs : (listof image) -> image > > Now, when I do: > (big-bang PIC-LIST > (on-draw choose-and-show-pairs)) > > I see each individual image getting laid out, one by one, rather > excrutiatingly slowly. The choose-and-show-pairs actually randomizes > the pairing up, and so if I move the mouse over the canvas, apparently > the redraw handler is called, so I see a new set of pairs getting laid > out, very slowly. > > I would have expected a double-buffered implementation to lay out the > images in memory on some bitmap buffer and then quickly transfer the > bitmap buffer to the canvas, so you don't actually witness the effect > of all the above/beside operations happening. > > >> >> >> >> >> On Sep 2, 2010, at 8:52 AM, Nadeem Abdul Hamid wrote: >> >>> Why doesn't 2htdp/universe use double-buffering? >>> >>> --- nadeem >>> _ >>> For list-related administrative tasks: >>> http://lists.racket-lang.org/listinfo/dev >> >> > > > > -- > Nadeem Abdul Hamid > Associate Professor, Computer Science > Berry College > PO Box 5014 > 2277 Martha Berry Hwy NW > Mount Berry, GA 30149-5014 > (706) 368-5632 > http://cs.berry.edu/~nhamid/ > _ > For list-related administrative tasks: > http://lists.racket-lang.org/listinfo/dev > _ For list-related administrative tasks: http://lists.racket-lang.org/listinfo/dev
Re: [racket-dev] Universe double buffering
What happens if you restart drracket and try the same program again? (If the double buffering appears to come back I think I know what happened.) Robby On Thu, Sep 2, 2010 at 8:15 AM, Nadeem Abdul Hamid wrote: >> Why do you think it doesn't? > > (I'm assuming you mean: "What makes me think that it is not > double-buffering?") ... > > I have a list of 15 thumbnail images of people and a function that > places pairs of them side by side, using above/beside to create a 133 > x 581 image. i.e. > choose-and-show-pairs : (listof image) -> image > > Now, when I do: > (big-bang PIC-LIST > (on-draw choose-and-show-pairs)) > > I see each individual image getting laid out, one by one, rather > excrutiatingly slowly. The choose-and-show-pairs actually randomizes > the pairing up, and so if I move the mouse over the canvas, apparently > the redraw handler is called, so I see a new set of pairs getting laid > out, very slowly. > > I would have expected a double-buffered implementation to lay out the > images in memory on some bitmap buffer and then quickly transfer the > bitmap buffer to the canvas, so you don't actually witness the effect > of all the above/beside operations happening. > > >> >> >> >> >> On Sep 2, 2010, at 8:52 AM, Nadeem Abdul Hamid wrote: >> >>> Why doesn't 2htdp/universe use double-buffering? >>> >>> --- nadeem >>> _ >>> For list-related administrative tasks: >>> http://lists.racket-lang.org/listinfo/dev >> >> > > > > -- > Nadeem Abdul Hamid > Associate Professor, Computer Science > Berry College > PO Box 5014 > 2277 Martha Berry Hwy NW > Mount Berry, GA 30149-5014 > (706) 368-5632 > http://cs.berry.edu/~nhamid/ > _ > For list-related administrative tasks: > http://lists.racket-lang.org/listinfo/dev > _ For list-related administrative tasks: http://lists.racket-lang.org/listinfo/dev
Re: [racket-dev] Universe double buffering
It still behaves the same. I can literally capture a screenshot of the canvas at any point where only a portion of the pictures have been drawn on it. On Thu, Sep 2, 2010 at 9:53 AM, Robby Findler wrote: > What happens if you restart drracket and try the same program again? > (If the double buffering appears to come back I think I know what > happened.) > > Robby > > On Thu, Sep 2, 2010 at 8:15 AM, Nadeem Abdul Hamid wrote: >>> Why do you think it doesn't? >> >> (I'm assuming you mean: "What makes me think that it is not >> double-buffering?") ... >> >> I have a list of 15 thumbnail images of people and a function that >> places pairs of them side by side, using above/beside to create a 133 >> x 581 image. i.e. >> choose-and-show-pairs : (listof image) -> image >> >> Now, when I do: >> (big-bang PIC-LIST >> (on-draw choose-and-show-pairs)) >> >> I see each individual image getting laid out, one by one, rather >> excrutiatingly slowly. The choose-and-show-pairs actually randomizes >> the pairing up, and so if I move the mouse over the canvas, apparently >> the redraw handler is called, so I see a new set of pairs getting laid >> out, very slowly. >> >> I would have expected a double-buffered implementation to lay out the >> images in memory on some bitmap buffer and then quickly transfer the >> bitmap buffer to the canvas, so you don't actually witness the effect >> of all the above/beside operations happening. >> >> >>> >>> >>> >>> >>> On Sep 2, 2010, at 8:52 AM, Nadeem Abdul Hamid wrote: >>> Why doesn't 2htdp/universe use double-buffering? --- nadeem _ _ For list-related administrative tasks: http://lists.racket-lang.org/listinfo/dev
