xcb-studies/notes.md

- A Display has Screens
- A Screen has Monitors & Windows
- The root Screen is accessed by traversing to the head of the list of
  screens using an interator.
- The root screen's root window is used as the parameter for
  'get_screen_resources'.
- The screen_resources object is contains 'screen_resources_crtcs',
  which you again get via an iterator. These are cookies.
Innteresting. It seems that the `output` collection is much more 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. 2022-02-24 23:59:43 +00:00			`- A Display has Screens`
			`- A Screen has Monitors & Windows`
			`- The root Screen is accessed by traversing to the head of the list of`
			`screens using an interator.`
			`- The root screen's root window is used as the parameter for`
			`'get_screen_resources'.`
			`- The screen_resources object is contains 'screen_resources_crtcs',`
			`which you again get via an iterator. These are cookies.`