idle: add a grace period

jay-config/src/_private/client.rs

@@ -893,6 +893,10 @@ impl Client {
         self.send(&ClientMessage::SetIdle { timeout })
     }
 
+    pub fn set_idle_grace_period(&self, period: Duration) {
+        self.send(&ClientMessage::SetIdleGracePeriod { period })
+    }
+
     pub fn set_explicit_sync_enabled(&self, enabled: bool) {
         self.send(&ClientMessage::SetExplicitSyncEnabled { enabled })
     }

jay-config/src/_private/ipc.rs

@@ -527,6 +527,9 @@ pub enum ClientMessage<'a> {
     SetXScalingMode {
         mode: XScalingMode,
     },
+    SetIdleGracePeriod {
+        period: Duration,
+    },
 }
 
 #[derive(Serialize, Deserialize, Debug)]

jay-config/src/lib.rs

@@ -224,10 +224,24 @@ pub fn workspaces() -> Vec<Workspace> {
 /// Configures the idle timeout.
 ///
 /// `None` disables the timeout.
+///
+/// The default is 10 minutes.
 pub fn set_idle(timeout: Option<Duration>) {
     get!().set_idle(timeout.unwrap_or_default())
 }
 
+/// Configures the idle grace period.
+///
+/// The grace period starts after the idle timeout expires. During the grace period, the
+/// screen goes black but the displays are not yet disabled and the idle callback (set
+/// with [`on_idle`]) is not yet called. This is a purely visual effect to inform the user
+/// that the machine will soon go idle.
+///
+/// The default is 5 seconds.
+pub fn set_idle_grace_period(timeout: Duration) {
+    get!().set_idle_grace_period(timeout)
+}
+
 /// Enables or disables explicit sync.
 ///
 /// Calling this after the compositor has started has no effect.