[Grustaf]

You can actually do it in UIKit by chopping it up into strips and using affine transforms, I've seen it done. Not that I think this is UIKit, it's probably a very simple OpenGL shader.

[zffr]

I doubt it was OpenGL/Metal directly. It is more likely to be something like CAMeshTransform (https://ciechanow.ski/mesh-transforms/)

[Grustaf]

Why? It's almost trivial to do it in OpenGL or Metal and the result will be better.