As far as I know, CoreGraphics is not implemented in GNUstep; I believe though that Cocotron has an implementation.
The error error: request for member ‘layer’ in something not a structure or union
refers to the expression view.layer
, which you intended to return the layer
property from the view
object. That syntax is from Objective-C 2.0, which wasn't supported out of the box with GNUstep, last I knew; check ObjC2FAQ for information about enabling it (and what its limitations on GNUstep are).
In the meantime, you can instead use the original Objective-C syntax: [view layer]
.