based on smithay library
interaction with the Operating System, this includes Session Management, Input Handling, and Graphics
winit
smithay provide winit backend based on the winit library, that can make compositor
run as wayland or x11 client. Useful for development and debugging.
from smithay docs:
Session management relates to mechanisms allowing the compositor to access the resources it needs to function. It contains interaction with the login manager if any ((e)logind or seatd), as well as releasing those resources when TTY-switching.
Compositor will generally need it to run directly on a TTY.
It is handled by smithays session module, gated by the backend_session cargo feature.
This module is tightly coupled with the udev module, which allows the discovery of usable graphics
and input devices on the system, using the udev system daemon.
udev
from arch wiki
udev is a userspace system that enables the operating system administrator to register userspace handlers for events. The events received by udev's daemon are mainly generated by the (Linux) kernel in response to physical events relating to peripheral devices.
Compositor can register a handlers to be notifed about physical events relating to peripheral devices.
It is handled by smithays udev module, gated by the backend_udev cargo feature.
Compositor can register handlers to be notifed about available input devices and all input events.
It is handled by smithays input module. An input provider based on libinput is given
in the libinput module, gated by the backend_libinput cargo feature.
Combining content from the clients and displaying it on the screen is the central role of a wayland compositor.
Smithay provides a rendering infrastructure built around graphics buffers: you retrieve buffers for your client, you composite them into a new buffer holding the contents of your desktop, that you will then submit to the hardware for display.
The backbone of this infrastructure is structured around the allocator and renderer modules.
allocator
Contains generic traits representing the capability to allocate and convert graphical buffers, as well as an implementation of this capability using GBM (see its module-level docs for details).
renderer
Provides traits representing the capability of graphics rendering using those buffers, as well as an implementation of this capability using GLes2 (see its module-level docs for details).
drm
Smithay provides the drm module, which represents abstraction on top the linux direct rendering manager api (drm).
This module is gated by the backend_drm cargo feature.
egl
Smithay provides the egl module, which provides the logic to setup an OpenGL context.
It is used by the Gles2 renderer (which is based on OpenGL), and also provides the capability
for clients to use the wl_drm-based hardware-acceleration provided by Mesa