reliable as a source of truth about which monitors and screens are
actually in use. Each one comes with its own collection of `crtc`,
but you can just skip the ones that return `null`, giving you a
reliable list of the "active and visible" screens that the user is
currently looking at. Excellent! This means that I'm one step closer
to having a viable solution!
I also discovered the [xcb_util](https://xcb.freedesktop.org/XcbUtil/)
library of helpful utilities has a function called
`xcb_aux_get_screen` for getting the root screen because everyone was
weirded out by that list traversal algorithm.
The source code to [xedgewarp](https://github.com/Airblader/xedgewarp)
was invaluable in revealing these secrets to me.
So far this little toy compiles down to only 35KB, and that includes
using `std::cout` and `std::vector`! I wonder how big the Rust
version will be. Yeah, yeah, I know, it cheats by having lots of
itself hidden in the kernel.
Next up: Actually knowing what the rotation status is.
