This has devolved into a fairly pointless semantic debate. What I'm saying is that rio is not built around compositing hardware surfaces, like all modern windowing systems (DWM, Mac CGS, Wayland) are. A windowing system that is not architected this way will always have inferior performance, and retrofitting the proper design onto an existing one based on memory buffers and drawing commands is difficult to do (see all the problems with XCOMPOSITE).