Add gamma control and night light (#38)

Add configurable night light, smooth gamma transitions, and shell controls. Update documentation and panel tests, and fix portal test startup synchronization.

compositor/src/handlers/gamma_control.rs

@@ -0,0 +1,97 @@
+use std::fs::File;
+
+use smithay::output::Output;
+use smithay::reexports::wayland_protocols_wlr::gamma_control::v1::server::{
+    zwlr_gamma_control_manager_v1::{self, ZwlrGammaControlManagerV1},
+    zwlr_gamma_control_v1::{self, ZwlrGammaControlV1},
+};
+use smithay::reexports::wayland_server::{Client, DataInit, Dispatch, DisplayHandle, GlobalDispatch, New, Resource};
+
+use crate::{Ferese, backends::direct::gamma, gamma::Ramp};
+
+pub(crate) fn init_global(display: &DisplayHandle) {
+    display.create_global::<Ferese, ZwlrGammaControlManagerV1, ()>(1, ());
+}
+
+impl GlobalDispatch<ZwlrGammaControlManagerV1, ()> for Ferese {
+    fn bind(
+        _state: &mut Self,
+        _display: &DisplayHandle,
+        _client: &Client,
+        resource: New<ZwlrGammaControlManagerV1>,
+        _data: &(),
+        data_init: &mut DataInit<'_, Self>,
+    ) {
+        data_init.init(resource, ());
+    }
+}
+
+impl Dispatch<ZwlrGammaControlManagerV1, ()> for Ferese {
+    fn request(
+        state: &mut Self,
+        _client: &Client,
+        _resource: &ZwlrGammaControlManagerV1,
+        request: zwlr_gamma_control_manager_v1::Request,
+        _data: &(),
+        _display: &DisplayHandle,
+        data_init: &mut DataInit<'_, Self>,
+    ) {
+        match request {
+            zwlr_gamma_control_manager_v1::Request::GetGammaControl { id, output } => {
+                let output = Output::from_resource(&output);
+                let control = data_init.init(id, output.clone());
+                if let Some(size) = output
+                    .as_ref()
+                    .and_then(|output| gamma::acquire(state, output, &control))
+                {
+                    control.gamma_size(size as u32);
+                } else {
+                    control.failed();
+                }
+            }
+            zwlr_gamma_control_manager_v1::Request::Destroy => {}
+            _ => unreachable!(),
+        }
+    }
+}
+
+impl Dispatch<ZwlrGammaControlV1, Option<Output>> for Ferese {
+    fn request(
+        state: &mut Self,
+        _client: &Client,
+        control: &ZwlrGammaControlV1,
+        request: zwlr_gamma_control_v1::Request,
+        output: &Option<Output>,
+        _display: &DisplayHandle,
+        _data_init: &mut DataInit<'_, Self>,
+    ) {
+        match request {
+            zwlr_gamma_control_v1::Request::SetGamma { fd } => {
+                let Some(output) = output else { return };
+                let Some(size) = gamma::size(state, output, control) else {
+                    return;
+                };
+                match Ramp::read(File::from(fd), size) {
+                    Ok(ramp) => gamma::set(state, output, control, ramp),
+                    Err(error) => control.post_error(
+                        zwlr_gamma_control_v1::Error::InvalidGamma,
+                        format!("Invalid gamma table: {error}"),
+                    ),
+                }
+            }
+            zwlr_gamma_control_v1::Request::Destroy => {}
+            _ => unreachable!(),
+        }
+    }
+
+    fn destroyed(
+        state: &mut Self,
+        _client: smithay::reexports::wayland_server::backend::ClientId,
+        control: &ZwlrGammaControlV1,
+        output: &Option<Output>,
+    ) {
+        if let Some(output) = output {
+            gamma::release(state, output, control);
+        }
+    }
+}

compositor/src/handlers/mod.rs

@@ -1,5 +1,6 @@
 pub(crate) mod activation;
 mod compositor;
+pub(crate) mod gamma_control;
 mod input_method;
 mod layer_shell;
 pub(crate) mod screencopy;