When I tried to generate the UIImage bindings, the generated code shows some errors:

The wrong code is generated as follow

....
  ffi.Pointer<CGImage> get CGImage {
    return _lib._objc_msgSend_1228(_id, _lib._sel_CGImage1);
  }
...
final class CGImage extends ffi.Opaque {}
...

Maybe the CGImage property should changed to cgImage?
https://developer.apple.com/documentation/coreimage/ciimage/1687603-cgimage