On 06/12/2008, at 6:32 AM, Andrew Coppin wrote:
Tim Docker wrote:
If you implement your drawing logic as a function from time to the appropriate render actions, ie
| import qualified Graphics.Rendering.Cairo as C | | type Animation = Time -> C.Render ()
then you just need to call this function multiple times to generate sucessive frames.
That was my initial idea... but I'm not sure how well it would work. I want to do stuff like fade elements in and out, move complex structures around on the screen, etc. I think it might end up being a little tangled if I go with this approach. I might be wrong though...
This model of animation as "a function of time to a picture" is probably described in many places. I first saw it described in Paul Hudaks book "The haskell School of Expression: Learning functional programming through multimedia". It shows how primitive animations can be combined in various ways, including overlays and time transformations. You can download the code from the books web-site, which might be of interest even if you can't get hold of a copy of the book. It's intended for pedagogical purposes, rather than a comprehensive animation system, of course. Tim