> On Apr 6, 2016, at 7:35 AM, Matthew Flatt <mfl...@cs.utah.edu> wrote: > > I haven't been able to replicate the problem, so far, even though my > machine and installation is similar to yours. > > Do you have a Racket installation on a different machine that you can > check? Whatever the problem is, my guess is that it's specific to OS X > (but that's just a guess). > > Does it matter whether you run the program in DrRacket or just through > `racket`?
I’m able to successfully replicate the problem on my machine at work. However, the problem does seem to be specific to DrRacket. Furthermore, I find that *restarting* DrRacket appears to solve the problem. If this workaround continues to work, then I suppose I won’t fret, though it’s a bit worrisome. I’ll file a bug report if I find that this becomes reproducible. Apologies for not trying to restart DrRacket earlier; I suppose this can be seen as a tribute to my belief in its stability? Thanks again for your time. John > > At Wed, 06 Apr 2016 00:17:51 -0400, "'John Clements' via Racket Users" wrote: >> I just wrote a simple 2htdp/universe program that animates a moving green >> rectangle. I was expecting to scale up to larger #s of rectangles, but I >> discover that moving the mouse affects the animation quite seriously. >> Specifically, moving the mouse in a small smooth circle causes the green >> rectangle to reduce its frame rate to about 7 frames per second. No GC >> activity is observed in the log box when gc@debug is added. >> >> I’m going to include the program below: I haven’t tried to minimize it, but >> it’s still quite small. (76 lines of HtDP style.) I’m guessing this problem >> is >> not specific to this program. >> >> FWIW, this is a 13” macbook pro, 16MB, running 10.11.4. >> >> Is this a known issue? >> >> John >> >> >> >> #lang racket >> >> (require 2htdp/universe >> 2htdp/image >> rackunit) >> >> (define r (rectangle 40 40 'solid 'green)) >> >> ;; represents a position on the screen >> (struct posn (x y) #:transparent) >> >> ;; a shape-transition contains an image, a starting >> ;; position, and an ending position. It represents >> ;; a shape that moves from the start-pos to the end-pos >> ;; through the transition >> (struct shapetrans (image start-pos end-pos) #:transparent) >> >> ;; in seconds: >> (define TRANSITION-TIME 1) >> >> ;; in frames per second >> (define FRAME-RATE 40) >> >> (define SCENEWIDTH 400) >> (define SCENEHEIGHT 300) >> >> (define transition-frames (* TRANSITION-TIME FRAME-RATE)) >> >> ;; given fraction of transition and shapetrans, compute >> ;; shape position >> (define (trans-posn frac st) >> (define 1-frac (- 1 frac)) >> (match st >> [(shapetrans _ (posn sx sy) (posn ex ey)) >> (posn (+ (* 1-frac sx) (* frac ex)) >> (+ (* 1-frac sy) (* frac ey)))])) >> >> (check-equal? (trans-posn 0 (shapetrans r (posn 10 30) (posn -50 100))) >> (posn 10 30)) >> (check-equal? (trans-posn 1/2 (shapetrans r (posn 10 30) (posn -50 100))) >> (posn -20 65)) >> (check-equal? (trans-posn 1 (shapetrans r (posn 10 30) (posn -50 100))) >> (posn -50 100)) >> >> ;; given fraction of transition, shapetrans, and scene, overlay >> ;; shapetrans-image at the correct location >> (define (add-image frac st scene) >> (match (trans-posn frac st) >> [(posn x y) >> (place-image (shapetrans-image st) x y scene)])) >> >> >> ;; a world is a shapetrans and a frame number >> (struct world (st frame)) >> >> ;; draw a world >> (define (draw-world w) >> (match-define (world st frame) w) >> (add-image (/ (modulo frame transition-frames) transition-frames) >> st >> (empty-scene SCENEWIDTH SCENEHEIGHT))) >> >> (check-equal? (draw-world (world (shapetrans r (posn 10 30) (posn 20 100)) >> (* 5/2 transition-frames))) >> (place-image r 15 65 (empty-scene SCENEWIDTH SCENEHEIGHT))) >> >> ;; advance the frame by 1 >> (define (tick-fun w) >> (match-define (world st frame) w) >> (world st (add1 frame))) >> >> (big-bang (world (shapetrans r (posn 10 30) (posn 20 100)) 0) >> [to-draw draw-world] >> [on-tick tick-fun (/ 1 FRAME-RATE)]) >> >> >> >> -- >> 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. >> >> ------------------------------------------------------------------------------ >> [application/pgp-signature "signature.asc"] [~/Desktop & open] [~/Temp & >> open] -- 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.
