Add support for window labels

docs/wiki/Configuration:-Window-Rules.md

@@ -37,6 +37,7 @@ window-rule {
     match is-window-cast-target=true
     match is-urgent=true
     match at-startup=true
+    match window-label="private" with-value="yes" with-no-value=true
 
     // Properties that apply once upon window opening.
     default-column-width { proportion 0.75; }
@@ -177,7 +178,7 @@ You can find the title and the app ID of a window by running `niri msg pick-wind
 
 > [!TIP]
 > Another way to find the window title and app ID is to configure the `wlr/taskbar` module in [Waybar](https://github.com/Alexays/Waybar) to include them in the tooltip:
-> 
+>
 > ```json
 > "wlr/taskbar": {
 >     "tooltip-format": "{title} | {app_id}",
@@ -318,6 +319,47 @@ window-rule {
 }
 ```
 
+#### `window-label`
+
+<sup>Since: 26.x</sup>
+
+Matches the windows by their assigned label by a regex on the label name. Each window can have multiple labels. Label has a name and optionally also a value.
+You can read about the supported regular expression syntax [here](https://docs.rs/regex/latest/regex/#syntax).
+
+The following properties can further limit the match by examining the value of the label that matches the `window-label`:
+
+* `with-value` - only matches if the label also has a matching value. This is also a regex.
+* `with-no-value` - only matches the label if it has no value.
+
+```kdl
+// Change the border for windows that are labeled "important"
+window-rule {
+  match window-label="important"
+
+  border {
+    active-color "#ee0000"
+    inactive-color "#ee5555"
+  }
+}
+
+binds {
+  Mod+F5 { toggle-label-on-focused-window "important"; }
+}
+```
+
+```kdl
+// Hide the windows labeled nsfw from screen cast
+window-rule {
+  match window-label="role" with-value="nsfw"
+
+  block-out-from "screencast"
+}
+
+binds {
+  Mod+F12 { set-label-on-focused-window "role" value="nsfw"; }
+}
+```
+
 ### Window Opening Properties
 
 These properties apply once, when a window first opens.
@@ -627,9 +669,10 @@ Can be `normal` or `tabbed`.
 
 This is used any time a window goes into its own column.
 For example:
-- Opening a new window.
-- Expelling a window into its own column.
-- Moving a window from the floating layout to the tiling layout.
+
+* Opening a new window.
+* Expelling a window into its own column.
+* Moving a window from the floating layout to the tiling layout.
 
 ```kdl
 // Make Evince windows open as tabbed columns.
@@ -905,7 +948,7 @@ window-rule {
 
 <video controls src="https://github.com/user-attachments/assets/3f4cb1a4-40b2-4766-98b7-eec014c19509">
 
-https://github.com/user-attachments/assets/3f4cb1a4-40b2-4766-98b7-eec014c19509
+<https://github.com/user-attachments/assets/3f4cb1a4-40b2-4766-98b7-eec014c19509>
 
 </video>
 

niri-config/src/binds.rs

@@ -389,6 +389,18 @@ pub enum Action {
     MruSetScope(MruScope),
     #[knuffel(skip)]
     MruCycleScope,
+    #[knuffel(skip)]
+    SetWindowLabel(u64, String, Option<String>),
+    #[knuffel(skip)]
+    UnsetWindowLabel(u64, String),
+    SetLabelOnFocusedWindow(
+        #[knuffel(argument)] String,
+        #[knuffel(property(name = "value"))] Option<String>,
+    ),
+    UnsetLabelOnFocusedWindow(#[knuffel(argument)] String),
+    #[knuffel(skip)]
+    ToggleWindowLabel(u64, String),
+    ToggleLabelOnFocusedWindow(#[knuffel(argument)] String),
 }
 
 impl From<niri_ipc::Action> for Action {
@@ -700,6 +712,20 @@ impl From<niri_ipc::Action> for Action {
             niri_ipc::Action::SetWindowUrgent { id } => Self::SetWindowUrgent(id),
             niri_ipc::Action::UnsetWindowUrgent { id } => Self::UnsetWindowUrgent(id),
             niri_ipc::Action::LoadConfigFile { path } => Self::LoadConfigFile(path),
+            niri_ipc::Action::SetWindowLabel { id, name, value } => {
+                Self::SetWindowLabel(id, name, value)
+            }
+            niri_ipc::Action::UnsetWindowLabel { id, name } => Self::UnsetWindowLabel(id, name),
+            niri_ipc::Action::SetLabelOnFocusedWindow { name, value } => {
+                Self::SetLabelOnFocusedWindow(name, value)
+            }
+            niri_ipc::Action::UnsetLabelOnFocusedWindow { name } => {
+                Self::UnsetLabelOnFocusedWindow(name)
+            }
+            niri_ipc::Action::ToggleWindowLabel { id, name } => Self::ToggleWindowLabel(id, name),
+            niri_ipc::Action::ToggleLabelOnFocusedWindow { name } => {
+                Self::ToggleLabelOnFocusedWindow(name)
+            }
         }
     }
 }

niri-config/src/lib.rs

@@ -1700,6 +1700,9 @@ mod tests {
                             is_window_cast_target: None,
                             is_urgent: None,
                             at_startup: None,
+                            window_label: None,
+                            with_value: None,
+                            with_no_value: None,
                         },
                     ],
                     excludes: [
@@ -1719,6 +1722,9 @@ mod tests {
                             is_window_cast_target: None,
                             is_urgent: None,
                             at_startup: None,
+                            window_label: None,
+                            with_value: None,
+                            with_no_value: None,
                         },
                         Match {
                             app_id: None,
@@ -1734,6 +1740,9 @@ mod tests {
                             is_window_cast_target: None,
                             is_urgent: None,
                             at_startup: None,
+                            window_label: None,
+                            with_value: None,
+                            with_no_value: None,
                         },
                     ],
                     default_column_width: None,

niri-config/src/window_rule.rs

@@ -94,6 +94,12 @@ pub struct Match {
     pub is_urgent: Option<bool>,
     #[knuffel(property)]
     pub at_startup: Option<bool>,
+    #[knuffel(property, str)]
+    pub window_label: Option<RegexEq>,
+    #[knuffel(property, str)]
+    pub with_value: Option<RegexEq>,
+    #[knuffel(property)]
+    pub with_no_value: Option<bool>,
 }
 
 #[derive(knuffel::Decode, Debug, Clone, Copy, PartialEq)]

niri-ipc/src/lib.rs

@@ -119,6 +119,11 @@ pub enum Request {
     OverviewState,
     /// Request information about screencasts.
     Casts,
+    /// Request window labels
+    WindowLabels {
+        /// Window id
+        id: u64,
+    },
 }
 
 /// Reply from niri to client.
@@ -165,6 +170,8 @@ pub enum Response {
     OverviewState(Overview),
     /// Information about screencasts.
     Casts(Vec<Cast>),
+    /// Information about the window labels
+    WindowLabels(Option<HashMap<String, Option<String>>>),
 }
 
 /// Overview information.
@@ -943,6 +950,62 @@ pub enum Action {
         #[cfg_attr(feature = "clap", arg(long))]
         path: Option<String>,
     },
+    /// Sets a label on a window
+    SetWindowLabel {
+        /// Id of the window.
+        #[cfg_attr(feature = "clap", arg(long))]
+        id: u64,
+
+        /// the name of the label
+        #[cfg_attr(feature = "clap", arg(long))]
+        name: String,
+
+        /// the value of the label
+        #[cfg_attr(feature = "clap", arg(long))]
+        value: Option<String>,
+    },
+    /// Unsets a label on a window
+    UnsetWindowLabel {
+        /// Id of the window.
+        #[cfg_attr(feature = "clap", arg(long))]
+        id: u64,
+
+        /// the name of the label
+        #[cfg_attr(feature = "clap", arg(long))]
+        name: String,
+    },
+    /// Set a label on the currently focused window
+    SetLabelOnFocusedWindow {
+        /// the name of the label
+        #[cfg_attr(feature = "clap", arg(long))]
+        name: String,
+
+        /// the value of the label
+        #[cfg_attr(feature = "clap", arg(long))]
+        value: Option<String>,
+    },
+    /// Unsets a label on the currenlty focused window
+    UnsetLabelOnFocusedWindow {
+        /// the name of the label
+        #[cfg_attr(feature = "clap", arg(long))]
+        name: String,
+    },
+    /// Toggles an unvalued label on a window
+    ToggleWindowLabel {
+        /// Id of the window.
+        #[cfg_attr(feature = "clap", arg(long))]
+        id: u64,
+
+        /// the name of the label
+        #[cfg_attr(feature = "clap", arg(long))]
+        name: String,
+    },
+    /// Toggles an unvalued label on the focused window
+    ToggleLabelOnFocusedWindow {
+        /// the name of the label
+        #[cfg_attr(feature = "clap", arg(long))]
+        name: String,
+    },
 }
 
 /// Change in window or column size.
@@ -1334,6 +1397,9 @@ pub struct Window {
     ///
     /// The timestamp comes from the monotonic clock.
     pub focus_timestamp: Option<Timestamp>,
+
+    ///Window labels
+    pub labels: Option<HashMap<String, Option<String>>>,
 }
 
 /// A moment in time.

src/cli.rs

@@ -109,6 +109,12 @@ pub enum Msg {
     OverviewState,
     /// List screencasts.
     Casts,
+    /// List window labels
+    WindowLabels {
+        /// Window id
+        #[arg()]
+        id: u64,
+    },
 }
 
 #[derive(Clone, Debug, clap::ValueEnum)]

src/input/mod.rs

@@ -2407,6 +2407,72 @@ impl State {
                     self.niri.queue_redraw_mru_output();
                 }
             }
+            Action::SetWindowLabel(id, name, value) => {
+                let window = self
+                    .niri
+                    .layout
+                    .workspaces_mut()
+                    .find_map(|ws| ws.windows_mut().find(|w| w.id().get() == id));
+                if let Some(window) = window {
+                    window.set_label(name, value);
+                    self.niri.queue_redraw_all();
+                }
+            }
+            Action::UnsetWindowLabel(id, name) => {
+                let window = self
+                    .niri
+                    .layout
+                    .workspaces_mut()
+                    .find_map(|ws| ws.windows_mut().find(|w| w.id().get() == id));
+                if let Some(window) = window {
+                    window.unset_label(name);
+                    self.niri.queue_redraw_all();
+                }
+            }
+            Action::SetLabelOnFocusedWindow(name, value) => {
+                let window = self
+                    .niri
+                    .layout
+                    .active_workspace_mut()
+                    .and_then(|ws| ws.active_window_mut());
+                if let Some(window) = window {
+                    window.set_label(name, value);
+                    self.niri.queue_redraw_all();
+                }
+            }
+            Action::UnsetLabelOnFocusedWindow(name) => {
+                let window = self
+                    .niri
+                    .layout
+                    .active_workspace_mut()
+                    .and_then(|ws| ws.active_window_mut());
+                if let Some(window) = window {
+                    window.unset_label(name);
+                    self.niri.queue_redraw_all();
+                }
+            }
+            Action::ToggleWindowLabel(id, name) => {
+                let window = self
+                    .niri
+                    .layout
+                    .workspaces_mut()
+                    .find_map(|ws| ws.windows_mut().find(|w| w.id().get() == id));
+                if let Some(window) = window {
+                    window.toggle_label(name);
+                    self.niri.queue_redraw_all();
+                }
+            }
+            Action::ToggleLabelOnFocusedWindow(name) => {
+                let window = self
+                    .niri
+                    .layout
+                    .active_workspace_mut()
+                    .and_then(|ws| ws.active_window_mut());
+                if let Some(window) = window {
+                    window.toggle_label(name);
+                    self.niri.queue_redraw_all();
+                }
+            }
         }
     }