Adapting co-ordinates for any screen size

My game features many sprites that always move along specific paths which are carefully mapped out according to the backgrounds and hard-coded using the SpriteKit coordinate system. This was originally done back in the days of only one iPad screen size, and the app was iPad only.

Of course, the iOS ecosystem is a very different place now, and I find myself wanting to address not only the fact that iPads are starting to come in all shapes and sizes, but also the increasing demands from users who want to run the app on their iPhones.

I have another app, one which works somewhat differently and does not require any animations. I’m currently reworking this one to be completely universal. It uses Autolayout constraints, and it’s been a painstaking process to position everything on screen using percentages within a container view with a fixed aspect ratio. It works well enough, so that things end up in more or less the same place regardless of the size or shape of the screen.

However, it’s clear to me that it would take me forever to do the same thing for my animations in the other app.

So the question is, what other solutions, if any, exist for mapping out multiple very specific paths on screen while adapting to different screen sizes and aspect ratios?

Is there even a solution to this, or are we stuck with using the “app requires full screen” option, which feels more like a temporary work-around than a real solution?