coregraphics

Profiling shows 80%-90% of the time is spent in texture upload and/or CoreGraphics.

You're probably gonna stay up at the CoreGraphics layer, use SpriteKit/SceneKit, or something like Cocos or something similar.

CoreGraphics) are absolutely capable of rendering at arbitrary resolutions, and have been for a long time.

That's not to say it was easy to make efficient, but it definitely outperforms the default CoreGraphics implementation on most content.

Also, it's super easy to create programmatic art for your app using the CoreGraphics API.

Very unlikely, I think they depend too much on OS X CoreGraphics and other libs to make porting feasible.

The UI layer is absolutely not portable: it's all low-level CoreGraphics code for the rendering, some CoreAnimation, and a ton of AppKit of course.

Regarding native complexity: surely, using CoreGraphics is just as easy as canvas?

Since this was a set of attributes for CoreGraphics graphics rendering, the dict/array conversion ended up costing magnitudes more than what the rendering itself did.

I've had some success using QC for prototyping animations and custom UI controls for iOS, then later hand coding them in CoreGraphics.

Random stuff you didn't expect like CoreGraphics would have showstopper issues and then we'd report it and it would get fixed by the next week.

* Have experience beyond UIKit - such as CoreGraphics, CoreText, iCloud, etc.