This is the initial implementation based on DRM dumb buffers,
which cleans up various things at the same time:
- DRM output is separate from GBM and DRM dumb buffer displays.
The latter two re-use the former.
- The timer refresh for the Vulkan KHR Display rendering lives
now with the KHR display code, in hope to be replaced with a
better mechanism in the future.
What's missing still is support for partial updates as well as
rendering with our own software renderer.
Remove the hack of calling present() from our swap_buffers() forwarder (and let it really only forward),
and instead call it explicitly through the shared egl_display member.
The way we can pass along the callback instead of storing it separately.
That's less boiler plate for us and better error handling (note how the receive_events()
call on the DRM device now propagates the error). And this also unregisters automatically
on drop.
... instead pass the fd into the calloop event loop and change state when we receive activity on it.
This improves performance slightly, and is a necessary to be able to implement refresh rate throttled rendering (in the next commits).
This patch adds support for the `SLINT_KMS_ROTATION` environment
variable, that instructs the Skia/FemtoVG renderers to rotate
the scene before rendering.
The cursor is loaded by the window adapter from the cache. When it's
loaded the first time, its format will be Svg, so we convert it to a
pixel buffer. That way the skia backend can convert it on first draw
into a skia_safe::Image and replace the cache entry with the backend
storage variant.
