I don't think you need to use Doubles for your positional data. You're talking about parts of a pixel. Pixels are so small, you aren't going to notice if a regular Float is a little bit off or slightly less accurate. I think you are wasting space with that. I'm not saying to not care about having it very precice positioning, just that a Double is not really giving you any benefit.
As to the animating itself it sounds like you're in the right direction. I don't know that you really need XML to store it, except as a file on a disk. There are more efficient formats for runtime - use an array or something.
As to the animating itself it sounds like you're in the right direction. I don't know that you really need XML to store it, except as a file on a disk. There are more efficient formats for runtime - use an array or something.