There are two separate questions here: how hard it would be to do such a thing in general
, and how hard it would be to incorporate that into the infrastructure that AAO has now.
Right now, AAO uses this image
. It sets the position in the viewport and then uses the transition css keyword to move from left to right. The fact that we use the transition css keyword limits us to certain kinds of ways to move the image around. What you want can be accomplished through something called a Bézier curve. While this can certainly be done
, Bézier curves are hard enough to work with that I think it would be better to select from a preset. So the answer to the first question: fairly straightforward.
Adding this to AAO is trickier. Currently, if you ask each frame what its transition is, it would tell you "true" or "false". Under this proposal, it isn't that simple! A frame could tell you, "false," "linear" (like it is now), "Bézier curve" (like it would have to be for your proposal), or maybe other options! We would need to rethink what kinds of transitions AAO will allow and how a frame will store those. Not an easy thing!