niri

https://niri-wm.github.io/niri/
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niri is a scrollable-tiling Wayland compositor designed with performance and rock-solid window...
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### Spawning Processes at Startup

Source: https://niri-wm.github.io/niri/Configuration%3A-Miscellaneous.html

Examples of how to spawn processes when niri starts.

```niri-config
spawn-at-startup "waybar"
spawn-at-startup "alacritty"

```

--------------------------------

### Spawn Action Example

Source: https://niri-wm.github.io/niri/Configuration%3A-Key-Bindings.html

Examples of using the 'spawn' action to run programs, including arguments.

```niri-config
binds {
    // Run alacritty.
    Mod+T { spawn "alacritty"; }

    // Run `wpctl set-volume @DEFAULT_AUDIO_SINK@ 0.1+`.
    XF86AudioRaiseVolume { spawn "wpctl" "set-volume" "@DEFAULT_AUDIO_SINK@" "0.1+"; }
}

```

--------------------------------

### Running Shell Commands at Startup

Source: https://niri-wm.github.io/niri/Configuration%3A-Miscellaneous.html

Example of running a shell command when niri starts.

```niri-config
// Pass all arguments in the same string.
spawn-sh-at-startup "qs -c ~/source/qs/MyAwesomeShell"

```

--------------------------------

### At Startup Matcher Example

Source: https://niri-wm.github.io/niri/Configuration%3A-Layer-Rules.html

Example of a layer rule that applies only during the first 60 seconds after niri starts, setting opacity to 0.5.

```config
layer-rule {
    match at-startup=true

    opacity 0.5
}

```

--------------------------------

### Wev Output Example

Source: https://niri-wm.github.io/niri/Configuration%3A-Key-Bindings.html

Example output from the `wev` tool, used to detect XKB key names.

```text
[14:     wl_keyboard] key: serial: 757775; time: 44940343; key: 113; state: 1 (pressed)
                      sym: Left         (65361), utf8: ''
[14:     wl_keyboard] key: serial: 757776; time: 44940432; key: 113; state: 0 (released)
                      sym: Left         (65361), utf8: ''
[14:     wl_keyboard] key: serial: 757777; time: 44940753; key: 114; state: 1 (pressed)
                      sym: Right        (65363), utf8: ''
[14:     wl_keyboard] key: serial: 757778; time: 44940846; key: 114; state: 0 (released)
                      sym: Right        (65363), utf8: ''


```

--------------------------------

### spawn-sh examples

Source: https://niri-wm.github.io/niri/Configuration%3A-Key-Bindings.html

Examples demonstrating the use of `spawn-sh` for running shell commands with various shell features like variables, tilde expansion, and process substitution.

```niri-config
binds {
    // Works with spawn-sh: all arguments in the same string.
    Mod+D { spawn-sh "alacritty -e /usr/bin/fish"; }

    // Works with spawn-sh: shell variable ($MAIN_OUTPUT), ~ expansion.
    Mod+T { spawn-sh "grim -o $MAIN_OUTPUT ~/screenshot.png"; }

    // Works with spawn-sh: process substitution.
    Mod+Q { spawn-sh "notify-send clipboard \"$(wl-paste)\"" ;}

    // Works with spawn-sh: multiple commands.
    Super+Alt+S { spawn-sh "pkill orca || exec orca"; }
}

```

--------------------------------

### Install dependencies on Fedora

Source: https://niri-wm.github.io/niri/Getting-Started.html

Install the required system dependencies for building niri on Fedora.

```bash
sudo dnf install gcc libudev-devel libgbm-devel libxkbcommon-devel wayland-devel libinput-devel dbus-devel systemd-devel libseat-devel pipewire-devel pango-devel cairo-gobject-devel clang libdisplay-info-devel
```

--------------------------------

### Basic Key Bindings Example

Source: https://niri-wm.github.io/niri/Configuration%3A-Key-Bindings.html

An example demonstrating how to declare key bindings in the `binds {}` section of the configuration file.

```config
binds {
    Mod+Left { focus-column-left; }
    Super+Alt+L { spawn "swaylock"; }
}

```

--------------------------------

### Install dependencies on Ubuntu 24.04

Source: https://niri-wm.github.io/niri/Getting-Started.html

Install the required system dependencies for building niri on Ubuntu 24.04.

```bash
sudo apt-get install -y gcc clang libudev-dev libgbm-dev libxkbcommon-dev libegl1-mesa-dev libwayland-dev libinput-dev libdbus-1-dev libsystemd-dev libseat-dev libpipewire-0.3-dev libpango1.0-dev libdisplay-info-dev
```

--------------------------------

### Install niri and DMS on Fedora

Source: https://niri-wm.github.io/niri/Getting-Started.html

Commands to enable the copr repository and install the necessary packages on Fedora.

```bash
sudo dnf copr enable avengemedia/dms
sudo dnf install niri dms
systemctl --user add-wants niri.service dms
```

--------------------------------

### Install niri and DMS on Ubuntu 25.10+

Source: https://niri-wm.github.io/niri/Getting-Started.html

Commands to add the required PPAs and install niri and DMS on Ubuntu 25.10 and above.

```bash
sudo add-apt-repository ppa:avengemedia/danklinux
sudo add-apt-repository ppa:avengemedia/dms
sudo apt install niri dms
```

--------------------------------

### Screen locker configuration example

Source: https://niri-wm.github.io/niri/FAQ.html

Example of how to configure a screen locker bind to allow unlocking when the screen is already locked.

```kdl
binds {
    Super+Alt+L allow-when-locked=true { spawn "swaylock"; }
}

```

--------------------------------

### Example Search Queries

Source: https://niri-wm.github.io/niri/niri_ipc/type.Reply.html?search=u32+-%3E+bool

Common examples of search queries used to find specific types or function signatures within the documentation.

```text
std::vec
u32 -> bool
Option<T>, (T -> U) -> Option<U>
```

--------------------------------

### Configure Output Properties

Source: https://niri-wm.github.io/niri/Configuration%3A-Outputs.html

Example showing all available properties for an output configuration block.

```niri
output "eDP-1" {
    // off
    mode "1920x1080@120.030"
    scale 2.0
    transform "90"
    position x=1280 y=0
    variable-refresh-rate // on-demand=true
    focus-at-startup
    backdrop-color "#001100"
    // max-bpc 8

    hot-corners {
        // off
        top-left
        // top-right
        // bottom-left
        // bottom-right
    }

    layout {
        // ...layout settings for eDP-1...
    }

    // Custom modes. Caution: may damage your display.
    // mode custom=true "1920x1080@100"
    // modeline 173.00  1920 2048 2248 2576  1080 1083 1088 1120 "-hsync" "+vsync"
}

output "HDMI-A-1" {
    // ...settings for HDMI-A-1...
}

output "Some Company CoolMonitor 1234" {
    // ...settings for CoolMonitor...
}
```

--------------------------------

### Serve documentation locally with uv

Source: https://niri-wm.github.io/niri/Development%3A-Documenting-niri.html

Commands to synchronize dependencies and start the local development server for the documentation site.

```bash
uv sync
uv run mkdocs serve
```

--------------------------------

### Install niri and DMS on Arch Linux

Source: https://niri-wm.github.io/niri/Getting-Started.html

Commands to install niri, DMS, and required dependencies on Arch Linux.

```bash
sudo pacman -Syu niri xwayland-satellite xdg-desktop-portal-gnome xdg-desktop-portal-gtk alacritty dms-shell-niri matugen cava qt6-multimedia-ffmpeg
systemctl --user add-wants niri.service dms
```

--------------------------------

### Basic include example

Source: https://niri-wm.github.io/niri/Configuration%3A-Include.html

Demonstrates a simple include statement within a configuration file.

```kdl
// Some settings...

include "colors.kdl"

// Some more settings...

```

--------------------------------

### Applying Rules at Startup

Source: https://niri-wm.github.io/niri/Configuration%3A-Window-Rules.html

Applies window rules specifically during the first 60 seconds after niri starts.

```KDL
// Open windows on the HDMI-A-1 monitor at niri startup, but not afterwards.
window-rule {
    match at-startup=true
    open-on-output "HDMI-A-1"
}
```

--------------------------------

### Merging example

Source: https://niri-wm.github.io/niri/Configuration%3A-Include.html

Illustrates how settings are merged between included files and the main configuration.

```kdl
// colors.kdl
layout {
    // Does not affect gaps, border width, etc.
    // Only changes colors as written.
    focus-ring {
        active-color "blue"
    }

    border {
        active-color "green"
    }
}

```

```kdl
// config.kdl
include "colors.kdl"

layout {
    // Does not set border and focus-ring colors,
    // so colors from colors.kdl are used.
    gaps 8

    border {
        width 8
    }
}

```

--------------------------------

### Configure classic window setup

Source: https://niri-wm.github.io/niri/Configuration%3A-Window-Rules.html

Combines border, geometry-corner-radius, and clip-to-geometry settings for a classic window appearance.

```niri
prefer-no-csd

layout {
    focus-ring {
        off
    }

    border {
        width 2
    }
}

window-rule {
    geometry-corner-radius 12
    clip-to-geometry true
}
```

--------------------------------

### Example Layer Rule

Source: https://niri-wm.github.io/niri/Configuration%3A-Layer-Rules.html

A comprehensive example demonstrating various matchers and properties for layer rules, including opacity, shadow, background effects, and pop-up configurations.

```config
layer-rule {
    match namespace="waybar"
    match at-startup=true
    match layer="top"

    // Properties that apply continuously.
    opacity 0.5
    block-out-from "screencast"
    // block-out-from "screen-capture"

    shadow {
        on
        // off
        softness 40
        spread 5
        offset x=0 y=5
        draw-behind-window true
        color "#00000064"
        // inactive-color "#00000064"
    }

    geometry-corner-radius 12
    place-within-backdrop true
    baba-is-float true

    background-effect {
        xray true
        blur true
        noise 0.05
        saturation 3
    }

    popups {
        opacity 0.5
        geometry-corner-radius 6

        background-effect {
            xray true
            blur true
            noise 0.05
            saturation 3
        }
    }
}

```

--------------------------------

### Binds override example

Source: https://niri-wm.github.io/niri/Configuration%3A-Include.html

Shows how `binds` sections override previously defined conflicting keys.

```kdl
// binds.kdl
binds {
    Mod+T { spawn "alacritty"; }
}

```

```kdl
// config.kdl
include "binds.kdl"

binds {
    // Overrides Mod+T from binds.kdl.
    Mod+T { spawn "foot"; }
}

```

--------------------------------

### Configuring Cursor Theme and Size

Source: https://niri-wm.github.io/niri/Configuration%3A-Miscellaneous.html

Example of setting the cursor theme and size.

```niri-config
cursor {
    xcursor-theme "breeze_cursors"
    xcursor-size 48
}

```

--------------------------------

### Example search queries

Source: https://niri-wm.github.io/niri/niri_ipc/type.Reply.html?search=

Common patterns for performing searches within the niri_ipc interface.

```text
  * std::vec
  * u32 -> bool
  * Option<T>, (T -> U) -> Option<U>
```

--------------------------------

### Window rule inclusion example

Source: https://niri-wm.github.io/niri/Configuration%3A-Include.html

Demonstrates how window rules are inserted at the position of the include statement.

```kdl
// rules.kdl
window-rule {
    match app-id="Alacritty"
    open-maximized false
}

```

```kdl
// config.kdl
window-rule {
    open-maximized true
}

// Window rules get inserted at this position.
include "rules.kdl"

window-rule {
    match app-id="firefox$"
    open-maximized true
}

```

```kdl
window-rule {
    open-maximized true
}

// Included from rules.kdl.
window-rule {
    match app-id="Alacritty"
    open-maximized false
}

window-rule {
    match app-id="firefox$"
    open-maximized true
}

```

--------------------------------

### Flags example

Source: https://niri-wm.github.io/niri/Configuration%3A-Include.html

Illustrates how flags can be disabled by setting them to `false` in included files.

```kdl
// csd.kdl

// Write "false" to explicitly disable.
prefer-no-csd false

```

```kdl
// config.kdl

// Enable prefer-no-csd in the main config.
prefer-no-csd

// Including csd.kdl will disable it again.
include "csd.kdl"

```

--------------------------------

### Set window size constraints

Source: https://niri-wm.github.io/niri/Configuration%3A-Window-Rules.html

Example of defining minimum and maximum dimensions for windows using a window-rule block.

```niri
window-rule {
    min-width 100
    max-width 200
    min-height 300
    max-height 300
}
```

--------------------------------

### Configure pop-up window rules

Source: https://niri-wm.github.io/niri/Configuration%3A-Window-Rules.html

Example of applying blur and geometry overrides to pop-ups for the Nautilus application.

```niri
// Blur the background behind pop-up menus in Nautilus.
window-rule {
    match app-id="Nautilus"

    popups {
        // Matches the default libadwaita pop-up corner radius.
        geometry-corner-radius 15

        // Note: it'll look better to set background opacity
        // through your GTK theme CSS and not here.
        // This is just an example that makes it look obvious.
        opacity 0.5

        background-effect {
            blur true
        }
    }
}
```

--------------------------------

### Non-merging sections example

Source: https://niri-wm.github.io/niri/Configuration%3A-Include.html

Demonstrates that sections like `struts` are not merged and the last definition wins.

```kdl
// struts.kdl
layout {
    struts {
        left 64
        right 64
    }
}

```

```kdl
// config.kdl
layout {
    struts {
        top 64
        bottom 64
    }
}

include "struts.kdl"

// Struts are not merged.
// End result is only left and right struts.

```

--------------------------------

### Kanshi configuration for multiple monitor setups

Source: https://niri-wm.github.io/niri/FAQ.html

Example Kanshi configuration to manage different output scaling and positioning based on connected monitors.

```kdl
profile {
    output eDP-1 enable scale 1.0
}

profile {
    output HDMI-A-1 enable scale 1.0 position 0,0
    output eDP-1 enable scale 1.25 position 1920,0
}

```

--------------------------------

### Complete Window Rule Configuration

Source: https://niri-wm.github.io/niri/Configuration%3A-Window-Rules.html

A comprehensive example showing all available matchers and properties that can be applied within a window-rule block.

```text
window-rule {
    match title="Firefox"
    match app-id="Alacritty"
    match is-active=true
    match is-focused=false
    match is-active-in-column=true
    match is-floating=true
    match is-window-cast-target=true
    match is-urgent=true
    match at-startup=true

    // Properties that apply once upon window opening.
    default-column-width { proportion 0.75; }
    default-window-height { fixed 500; }
    open-on-output "Some Company CoolMonitor 1234"
    open-on-workspace "chat"
    open-maximized true
    open-maximized-to-edges true
    open-fullscreen true
    open-floating true
    open-focused false

    // Properties that apply continuously.
    draw-border-with-background false
    opacity 0.5
    block-out-from "screencast"
    // block-out-from "screen-capture"
    variable-refresh-rate true
    default-column-display "tabbed"
    default-floating-position x=100 y=200 relative-to="bottom-left"
    scroll-factor 0.75
    on-xdg-activate "focus"

    focus-ring {
        // off
        on
        width 4
        active-color "#7fc8ff"
        inactive-color "#505050"
        urgent-color "#9b0000"
        // active-gradient from="#80c8ff" to="#bbddff" angle=45
        // inactive-gradient from="#505050" to="#808080" angle=45 relative-to="workspace-view"
        // urgent-gradient from="#800" to="#a33" angle=45
    }

    border {
        // Same as focus-ring.
    }

    shadow {
        // on
        off
        softness 40
        spread 5
        offset x=0 y=5
        draw-behind-window true
        color "#00000064"
        // inactive-color "#00000064"
    }

    tab-indicator {
        active-color "red"
        inactive-color "gray"
        urgent-color "blue"
        // active-gradient from="#80c8ff" to="#bbddff" angle=45
        // inactive-gradient from="#505050" to="#808080" angle=45 relative-to="workspace-view"
        // urgent-gradient from="#800" to="#a33" angle=45
    }

    geometry-corner-radius 12
    clip-to-geometry true
    tiled-state true
    baba-is-float true

    background-effect {
        xray true
        blur true
        noise 0.05
        saturation 3
    }

    popups {
        opacity 0.5
        geometry-corner-radius 15

        background-effect {
            xray true
            blur true
            noise 0.05
            saturation 3
        }
    }

    min-width 100
    max-width 200
    min-height 300
    max-height 300
}
```

--------------------------------

### Namespace Matcher Example

Source: https://niri-wm.github.io/niri/Configuration%3A-Layer-Rules.html

Example of a layer rule that matches surfaces with a namespace containing 'waybar'.

```config
layer-rule {
    match namespace="waybar"
}

```

--------------------------------

### Place Within Backdrop Example

Source: https://niri-wm.github.io/niri/Configuration%3A-Layer-Rules.html

Example of a layer rule to place swaybg (namespace '^wallpaper$') into the overview backdrop.

```config
layer-rule {
    match namespace="^wallpaper$"

    place-within-backdrop true
}

```

--------------------------------

### Block Out From Screencast Example

Source: https://niri-wm.github.io/niri/Configuration%3A-Layer-Rules.html

Example of a layer rule to block out mako notifications from screencasts by matching the namespace '^notifications$'.

```config
layer-rule {
    match namespace="^notifications$"

    block-out-from "screencast"
}

```

--------------------------------

### Localectl Command Example

Source: https://niri-wm.github.io/niri/Configuration%3A-Input.html

Illustrates using localectl to set X11 keymap and displays the output of localectl, showing system locale and keymap settings.

```shell
$ localectl set-x11-keymap "us" "" "colemak_dh_ortho" "compose:ralt,ctrl:nocaps"
$ localectl
System Locale: LANG=en_US.UTF-8
               LC_NUMERIC=ru_RU.UTF-8
               LC_TIME=ru_RU.UTF-8
               LC_MONETARY=ru_RU.UTF-8
               LC_PAPER=ru_RU.UTF-8
               LC_MEASUREMENT=ru_RU.UTF-8
    VC Keymap: us-colemak_dh_ortho
   X11 Layout: us
  X11 Variant: colemak_dh_ortho
  X11 Options: compose:ralt,ctrl:nocaps


```

--------------------------------

### Layer Matcher Example

Source: https://niri-wm.github.io/niri/Configuration%3A-Layer-Rules.html

Example of a layer rule that matches surfaces on the 'overlay' layer-shell layer and sets them to be float.

```config
layer-rule {
    match layer="overlay"

    baba-is-float true
}

```

--------------------------------

### Configure open-fullscreen

Source: https://niri-wm.github.io/niri/Configuration%3A-Window-Rules.html

Sets the initial fullscreen state for a window.

```niri
window-rule {
    open-fullscreen true
}
```

```niri
// Make the Telegram media viewer open in windowed mode.
window-rule {
    match app-id=r#"^org\.telegram\.desktop$"# title="^Media viewer$"

    open-fullscreen false
}
```

--------------------------------

### Configure startup focus

Source: https://niri-wm.github.io/niri/Configuration%3A-Outputs.html

Sets the default output to focus upon niri startup. Prioritization follows the order of appearance in the configuration.

```niri
// Focus HDMI-A-1 by default.
output "HDMI-A-1" {
    focus-at-startup
}

// ...if HDMI-A-1 wasn't connected, focus DP-2 instead.
output "DP-2" {
    focus-at-startup
}
```

--------------------------------

### Opacity Property Example

Source: https://niri-wm.github.io/niri/Configuration%3A-Layer-Rules.html

Example of a layer rule to make fuzzel (identified by namespace '^launcher$') semitransparent with an opacity of 0.95.

```config
layer-rule {
    match namespace="^launcher$"

    opacity 0.95
}

```

--------------------------------

### Run niri with NixGL

Source: https://niri-wm.github.io/niri/Getting-Started.html

Use NixGL to run the niri binary if you are not on NixOS.

```bash
nix run --impure github:guibou/nixGL -- ./results/bin/niri
```

--------------------------------

### Geometry Corner Radius Example

Source: https://niri-wm.github.io/niri/Configuration%3A-Layer-Rules.html

Example of a layer rule to set the geometry corner radius for a surface identified by namespace '^launcher$'.

```config
layer-rule {
    match namespace="^launcher$"

    geometry-corner-radius 12
}

```

--------------------------------

### Mirror output with wl-mirror

Source: https://niri-wm.github.io/niri/Screencasting.html

Configure a keybind to mirror the focused output to a window using wl-mirror.

```niri-config
binds {
    Mod+P repeat=false { spawn-sh "wl-mirror $(niri msg --json focused-output | jq -r .name)"; }
}
```

--------------------------------

### Shadow and Corner Radius Example for Fuzzel

Source: https://niri-wm.github.io/niri/Configuration%3A-Layer-Rules.html

Example of a layer rule to add a shadow and set corner radius for fuzzel (namespace '^launcher$').

```config
layer-rule {
    match namespace="^launcher$"

    shadow {
        on
    }

    // Fuzzel defaults to 10 px rounded corners.
    geometry-corner-radius 10
}

```

--------------------------------

### Get Niri Outputs in JSON

Source: https://niri-wm.github.io/niri/IPC.html

Use the `--json` flag with `niri msg` to get structured output for commands like 'outputs'. This is useful for scripting and automated processing.

```bash
niri msg --json outputs
```

--------------------------------

### Result::is_err Example

Source: https://niri-wm.github.io/niri/niri_ipc/type.Reply.html?search=

Checks if the result is Err.

```rust
let x: Result<i32, &str> = Ok(-3);
assert_eq!(x.is_err(), false);

let x: Result<i32, &str> = Err("Some error message");
assert_eq!(x.is_err(), true);
```

--------------------------------

### Result::is_ok Example

Source: https://niri-wm.github.io/niri/niri_ipc/type.Reply.html?search=

Checks if the result is Ok.

```rust
let x: Result<i32, &str> = Ok(-3);
assert_eq!(x.is_ok(), true);

let x: Result<i32, &str> = Err("Some error message");
assert_eq!(x.is_ok(), false);
```

--------------------------------

### Run X11 applications with xwayland-run

Source: https://niri-wm.github.io/niri/Xwayland.html

Use xwayland-run to automatically manage the lifecycle of a rootful Xwayland server for specific X11 applications.

```bash
xwayland-run <Xwayland arguments> -- your-x11-app <X11 app arguments>
```

```bash
xwayland-run -geometry 800x600 -fullscreen -- wine wingame.exe
```

--------------------------------

### into_ok usage

Source: https://niri-wm.github.io/niri/niri_ipc/type.Reply.html?search=

Example of using into_ok to extract the Ok value.

```rust
let s: String = only_good_news().into_ok();
println!("{s}");
```

--------------------------------

### Result::into_ok usage

Source: https://niri-wm.github.io/niri/niri_ipc/type.Reply.html?search=

Example of using the nightly-only into_ok method.

```rust
fn only_good_news() -> Result<String, !> {
    Ok("this is fine".into())
}
```

--------------------------------

### Result::as_ref Example

Source: https://niri-wm.github.io/niri/niri_ipc/type.Reply.html?search=

Converts a Result reference to a Result of references.

```rust
let x: Result<u32, &str> = Ok(2);
assert_eq!(x.as_ref(), Ok(&2));

let x: Result<u32, &str> = Err("Error");
assert_eq!(x.as_ref(), Err(&"Error"));
```

--------------------------------

### Result::ok Example

Source: https://niri-wm.github.io/niri/niri_ipc/type.Reply.html?search=

Converts Result to Option, discarding the error.

```rust
let x: Result<u32, &str> = Ok(2);
assert_eq!(x.ok(), Some(2));

let x: Result<u32, &str> = Err("Nothing here");
assert_eq!(x.ok(), None);
```

--------------------------------

### Example of including a border configuration

Source: https://niri-wm.github.io/niri/Configuration%3A-Include.html

This snippet shows how to configure the border in a separate KDL file, including the necessary 'on' directive.

```kdl
// separate.kdl
layout {
    border {
        // Add this line:
        on

        width 4
        active-color "#ffc87f"
        inactive-color "#505050"
    }
}

```

--------------------------------

### Result::is_err_and Example

Source: https://niri-wm.github.io/niri/niri_ipc/type.Reply.html?search=

Checks if the result is Err and matches a predicate.

```rust
use std::io::{Error, ErrorKind};

let x: Result<u32, Error> = Err(Error::new(ErrorKind::NotFound, "!"));
assert_eq!(x.is_err_and(|x| x.kind() == ErrorKind::NotFound), true);

let x: Result<u32, Error> = Err(Error::new(ErrorKind::PermissionDenied, "!"));
assert_eq!(x.is_err_and(|x| x.kind() == ErrorKind::NotFound), false);

let x: Result<u32, Error> = Ok(123);
assert_eq!(x.is_err_and(|x| x.kind() == ErrorKind::NotFound), false);

let x: Result<u32, String> = Err("ownership".to_string());
assert_eq!(x.as_ref().is_err_and(|x| x.len() > 1), true);
println!("still alive {:?}", x);
```

--------------------------------

### Override Window Rules

Source: https://niri-wm.github.io/niri/Configuration%3A-Window-Rules.html

Demonstrates how to set a global rule and then override it for a specific application using the app-id.

```text
// Set open-maximized to true for all windows.
window-rule {
    open-maximized true
}

// Then, for Alacritty, set open-maximized back to false.
window-rule {
    match app-id="Alacritty"
    open-maximized false
}
```

--------------------------------

### Build with Tracy profiler

Source: https://niri-wm.github.io/niri/Development%3A-Developing-niri.html

Compile niri with Tracy integration for performance analysis.

```bash
cargo build --release --features=profile-with-tracy-ondemand
```

```bash
cargo build --release --features=profile-with-tracy
```

--------------------------------

### Result::is_ok_and Example

Source: https://niri-wm.github.io/niri/niri_ipc/type.Reply.html?search=

Checks if the result is Ok and matches a predicate.

```rust
let x: Result<u32, &str> = Ok(2);
assert_eq!(x.is_ok_and(|x| x > 1), true);

let x: Result<u32, &str> = Ok(0);
assert_eq!(x.is_ok_and(|x| x > 1), false);

let x: Result<u32, &str> = Err("hey");
assert_eq!(x.is_ok_and(|x| x > 1), false);

let x: Result<String, &str> = Ok("ownership".to_string());
assert_eq!(x.as_ref().is_ok_and(|x| x.len() > 1), true);
println!("still alive {:?}", x);
```

--------------------------------

### baba-is-float

Source: https://niri-wm.github.io/niri/Configuration%3A-Layer-Rules.html

Example of making a layer surface float up and down.

```niri-config
// Make fuzzel FLOAT.
layer-rule {
    match namespace="^launcher$"

    baba-is-float true
}

```

--------------------------------

### Launch Steam with Gamescope

Source: https://niri-wm.github.io/niri/Xwayland.html

Run Steam inside a Gamescope session to handle X11 games.

```bash
gamescope -- flatpak run com.valvesoftware.Steam
```

```bash
gamescope -W 2560 -H 1440 -w 2560 -h 1440 -f  -- flatpak run com.valvesoftware.Steam
```

--------------------------------

### Result::err Example

Source: https://niri-wm.github.io/niri/niri_ipc/type.Reply.html?search=

Converts Result to Option, discarding the success value.

```rust
let x: Result<u32, &str> = Ok(2);
assert_eq!(x.err(), None);

let x: Result<u32, &str> = Err("Nothing here");
assert_eq!(x.err(), Some("Nothing here"));
```

--------------------------------

### State Transition

Source: https://niri-wm.github.io/niri/src/niri_ipc/state.rs.html

Example of handling state transitions.

```rust
impl State {
    pub fn transition(&mut self, event: Event) {
        match (self, event) {
            (State::Idle, Event::Start) => *self = State::Running,
            (State::Running, Event::Pause) => *self = State::Paused,
            (State::Running, Event::Stop) => *self = State::Stopped,
            (State::Paused, Event::Start) => *self = State::Running,
            (State::Paused, Event::Stop) => *self = State::Stopped,
            _ => { /* Ignore invalid transitions */ }
        }
    }
}

```

--------------------------------

### Spawn with Shell Expansion

Source: https://niri-wm.github.io/niri/Configuration%3A-Key-Bindings.html

Using 'sh -c' to enable shell expansion for environment variables, tilde expansion, pipes, and multiple commands in 'spawn' actions.

```niri-config
binds {
    // Wrong: no shell expansion here. These strings will be passed literally to the program.
    Mod+T { spawn "grim" "-o" "$MAIN_OUTPUT" "~/screenshot.png"; }

    // Correct: run this through a shell manually so that it can expand the arguments.
    // Note that the entire command is passed as a SINGLE argument,
    // because shell will do its own argument splitting by whitespace.
    Mod+D { spawn "sh" "-c" "grim -o $MAIN_OUTPUT ~/screenshot.png"; }

    // You can also use a shell to run multiple commands,
    // use pipes, process substitution, and so on.
    Mod+Q { spawn "sh" "-c" "notify-send clipboard \"$(wl-paste)\" "; }
}

```

--------------------------------

### Enable Shadows

Source: https://niri-wm.github.io/niri/Configuration%3A-Layout.html

Example of enabling shadows for windows.

```niri-config
// Enable shadows.
layout {
    shadow {
        on
    }
}

// Also ask windows to omit client-side decorations, so that
// they don't draw their own window shadows.
prefer-no-csd

```

--------------------------------

### Define Layout and Workspace Commands

Source: https://niri-wm.github.io/niri/src/niri_ipc/lib.rs.html

Commands for switching keyboard layouts, showing overlays, and moving workspaces between monitors.

```rust
/// Switch between keyboard layouts.
SwitchLayout {
    /// Layout to switch to.
    #[cfg_attr(feature = "clap", arg())]
    layout: LayoutSwitchTarget,
},
/// Show the hotkey overlay.
ShowHotkeyOverlay {},
/// Move the focused workspace to the monitor to the left.
MoveWorkspaceToMonitorLeft {},
/// Move the focused workspace to the monitor to the right.
MoveWorkspaceToMonitorRight {},
/// Move the focused workspace to the monitor below.
MoveWorkspaceToMonitorDown {},
/// Move the focused workspace to the monitor above.
MoveWorkspaceToMonitorUp {},
/// Move the focused workspace to the previous monitor.
MoveWorkspaceToMonitorPrevious {},
/// Move the focused workspace to the next monitor.
MoveWorkspaceToMonitorNext {},
/// Move a workspace to a specific monitor.
#[cfg_attr(
    feature = "clap",
    clap(about = "Move the focused workspace to a specific monitor")
)]
MoveWorkspaceToMonitor {
    /// The target output name.
    #[cfg_attr(feature = "clap", arg())]
    output: String,

    // Reference (index or name) of the workspace to move.
    ///
    /// If `None`, uses the focused workspace.
    #[cfg_attr(feature = "clap", arg(long))]
    reference: Option<WorkspaceReferenceArg>,
},
```
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