Comment by willtemperley

Quartz 2D is now CoreGraphics. It's hard to find information about the backend, presumably for commercial reasons. I do know it uses the GPU for some operations like magnifyEffect.

Today I was smoothly panning and zooming 30K vertex polygons with SwiftUI Canvas and it was barely touching the CPU so I suspect it uses the GPU heavily. Either way it's getting very good. There's barely any need to use render caches.