[racket] Facing some flickering problems

From: Robby Findler (robby at eecs.northwestern.edu)
Date: Thu Jul 22 21:06:01 EDT 2010

If you define the images at the top-level of your program and then
just refer to the variables, that is what will happen. It may or may
not speed up drawing, however, depending if what is slow is the actual
drawing or not.

Performance debugging is not as easy as writing the program in the
first place. There are lots of things that can make a program slow.
(This is just meant as a warning that it may not be a short road to
the answer.)


On Thu, Jul 22, 2010 at 8:00 PM, Mathew Kurian <bluejamesbond at gmail.com> wrote:
> i am using the racket build with 2htdp/image
> and 2htdp/universe and capping the memory at 512 MB. Is there anyway, I can
> preload the images for universe and then use them (almost like the java
> way). Or is there some place i can store the images in some sort of hash
> map.
> Basically, instead of loading images at the second you use them, can you
> load it at the beginning of running a program.
> On Thu, Jul 22, 2010 at 2:37 PM, Matthias Felleisen <matthias at ccs.neu.edu>
> wrote:
>> On Jul 22, 2010, at 2:25 PM, Mathew Kurian wrote:
>> > Yes, Matthias...mine is using universe, so i don't think i can pesonally
>> > implement double buffering... i think it is caused from the game being to
>> > large...but its just a thought you guys are the pros, so you teach me.
>> >
>> > I have a lot of transparency in my images...i personally make them using
>> > fireworks and photoshop, so that too might be an issue.
>> We have noticed performance problems in 2htdp/universe and images before.
>> So which image package are you using and can you describe the conditions
>> under which you see flickering? (I am assuming that you're running 5.0.)
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