On Sat, Apr 29, 2017 at 2:10 AM, WarGrey Gyoudmon Ju <juzhenli...@gmail.com> wrote:
> Hello, I think the main reason that pict is faster than 2htdp/image is, > the pict is implemented with struct while the 2htdp/image is implemented > with class, the speed of rendering is just as fast/slow as each other, but > manipulation on class is much heavier than on struct when combining large > numbers of shapes. Maybe you want to check the code of `table` in pict-lib, > it is a good example to place shapes into grids in a functional way. > Interesting. I'd also note that unlike pict 2htdp/image doesn't provide a way to draw direct to dc, necessitating going via bitmaps when using it in conjunction with racket/gui. > I tested your example with my functional bitmap APIs (with arguments > memorized, and it only creates one bitmap% when combining a list of > shapes), as expected it is too slow(<3s, without memorizing it's <6s) to > stand with, but it also indicates that half or less time used is not > creating or drawing single primitive shapes, but every primitive shape is > rendered duplicately whenever its combining shape is rendering. So the > issue is, to find a strategy to call `freeze` at a reasonable level of > combined shapes. > My thinking has been to strip back to simpler strategies initially to see how much speed is possible, then apply freezing and caching strategies later, if applicable. (Something, something "premature optimization ... evil" ;-) > > One reason that you may have to write your own combiner(here the term > should be "layout") is, `freeze` can make a big shape, but it cannot avoid > the duplicate rendering since it actually do the drawing. So your combiner > would focus on providing the position and size information for dc to `draw` > or `copy` and/or `rotate/flip`. Sounds hard to do it with fewer bugs. > Before resorting to writing my own combiner / layout I think I'll see what performance I can get from a custom "block" pict. From the pict library's POV this would reduce the number of picts in my examples from 1000s to 1. Thanks Dan -- 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.
