By the skin of my teeth, and JUST for the end of #marchintosh, I'm releasing libmui which is a Linux UI interface library heavily inspired by MacOS classic (and GS/OS!). https://github.com/buserror/libmui
GitHub - buserror/libmui: Classic MacOS & GS/OS widget library for linux (and other?)

Classic MacOS & GS/OS widget library for linux (and other?) - buserror/libmui

GitHub

@buserror Honestly, it's kind of embarrassing how quickly I darted over to your github mirror and cloned the sources to my macbook.

Thank you; this is evil, but in a good way!

@buserror I really like the underlying header-only C graphics libraries. Render directly to an RGBA surface with no dependencies whatsoever, then just use OpenGL or whatever else you have to blit it to the screen. Inefficient, perhaps, but still more efficient than IMGUI, and it's the most portable API possible!