Paneru

A sliding, tiling window manager for MacOS.

About

Paneru is a MacOS window manager that arranges windows on an infinite strip, extending to the right. A core principle is that opening a new window will never cause existing windows to resize, maintaining your layout stability.

Each monitor operates with its own independent window strip, ensuring that windows remain confined to their respective displays and do not "overflow" onto adjacent monitors.

paneru.mp4

Why Paneru?

• Niri-like Behavior on MacOS: Inspired by the user experience of Niri, Paneru aims to bring a similar scrollable tiling workflow to MacOS.
• Works with MacOS workspaces: You can use existing workspaces and switch between them with keyboard or touchpad gestures - with a separate window strip on each. Drag and dropping windows between them works as well.
• Focus follows mouse on MacOS: Very useful for people who would like to avoid an extra click.
• Sliding windows with touchpad: Using a touchpad is quite natural for navigation of the window pane.
• Optimal for Large Displays: Standard tiling window managers can be suboptimal for large displays, often resulting in either huge maximized windows or numerous tiny, unusable windows. Paneru addresses this by providing a more flexible and practical arrangement.
• Improved Small Display Usability: On smaller displays (like laptops), traditional tiling can make windows too small to be productive, forcing users to constantly maximize. Paneru's sliding strip approach aims to provide a better experience without this compromise.

Inspiration

The fundamental architecture and window management techniques are heavily inspired by Yabai, another excellent MacOS window manager. Studying its source code has provided invaluable insights into managing windows on MacOS, particularly regarding undocumented functions.

The innovative concept of managing windows on a sliding strip is directly inspired by Niri and PaperWM.spoon.

Installation

Recommended System Options

• Like all non-native window managers for MacOS, Paneru requires accessibility access to move windows. Once it runs you may get a dialog window asking for permissions. Otherwise check the setting in System Settings under "Privacy & Security -> Accessibility".

• Check your System Settings for "Displays have separate spaces" option. It should be enabled - this allows Paneru to manage the workspaces independently.

• Multiple displays. Paneru is moving the windows off-screen, hiding them to the left or right. If you have multiple displays, for example your laptop open when docked to an external monitor you may experience weird behavior. The issue is that when MacOS notices a window being moved too far off-screen it will relocate it to a different display - which confuses Paneru! The solution is to change the spatial arrangement of your additional display - instead of having it to the left or right, move it above or below your main display. A similar situation exists with Aerospace window manager.

Installing from Crates.io

Paneru is built using Rust's cargo. It can be installed directly from crates.io or if you need the latest version, by fetching the source from Github.

$ cargo install paneru

Installing from Github

$ git clone https://github.com/karinushka/paneru.git 
$ cd paneru
$ cargo build --release
$ cargo install --path .

It can run directly from the command line or as a service. Note, that you will need to grant acessibility priviledge to the binary.

Installing with Nix

Add the paneru flake to your inputs.

# flake.nix
inputs.paneru = {
  url = "github:karinushka/paneru";
  inputs.nixpkgs.follows = "nixpkgs";
}

Home Manager

Paneru provides a home manager module to install and configure paneru.

Note

You still need to enable accessibility permissions in the macOS settings the first time paneru is launched or any time it is updated.

# home.nix
{ inputs, ... }:

{
  imports = [
    inputs.paneru.homeModules.paneru
  ];

  services.paneru = {
    enable = true;
    # Equivalent to what you would put into `~/.paneru` (See Configuration options below).
    settings = {
      options = {
        preset_column_widths = [
          0.25
          0.33
          0.5
          0.66
          0.75
        ];
        swipe_gesture_fingers = 4;
        animation_speed = 4000;
      };
      bindings = {
        window_focus_west = "cmd - h";
        window_focus_east = "cmd - l";
        window_focus_north = "cmd - k";
        window_focus_south = "cmd - j";
        window_swap_west = "alt - h";
        window_swap_east = "alt - l";
        window_swap_first = "alt + shift - h";
        window_swap_last = "alt + shift - l";
        window_center = "alt - c";
        window_resize = "alt - r";
        window_fullwidth = "alt - f";
        window_manage = "ctrl + alt - t";
        window_stack = "alt - ]";
        window_unstack = "alt + shift - ]";
        quit = "ctrl + alt - q";
      };
    };
  };
}

Standalone Package

Although we strongly recommend using home manager, the paneru flake also exposes a standalone package.

{ inputs, ... }:

{
  # nix-darwin configuration (configuration.nix)
  # system-wide
  environment.systemPackages = [ inputs.paneru.packages.paneru ]
  # or per-user
  users.users."<name>".packages = [ inputs.paneru.packages.paneru ]
}

Configuration

Paneru checks for configuration in following locations:

• $HOME/.paneru
• $HOME/.paneru.toml
• $XDG_CONFIG_HOME/paneru/paneru.toml

Additionally it allows overriding the location with $PANERU_CONFIG environment variable.

You can use the following example configuration as a starting point:

# syntax=toml
#
# Example configuration for Paneru.
#
[options]
# Enables focus follows mouse. Enabled by default, set to false to disable.
# focus_follows_mouse = true

# Enables mouse follows focus. Enabled by default, set to false to disable.
# mouse_follows_focus = true

# Array of widths used by the `window_resize` action to cycle between.
# Defaults to 25%, 33%, 50%, 66% and 75%.
preset_column_widths = [ 0.25, 0.33, 0.50, 0.66, 0.75 ]

# How many fingers to use for moving windows left and right.
# Make sure that it doesn't clash with OS setting for workspace switching.
# Values lower than 3 will be ignored.
# Remove the line to disable the gesture feature.
# Apple touchpads support gestures with more than five fingers (!),
# but it is probably not that useful to use two hands :)
swipe_gesture_fingers = 4

# Swiping the windows left and right will keep sliding them until the first or
# last window. Set to false to always keep the current window on screen and
# fully exposed. Enabled by default.
# continuous_swipe = true

# Animation speed in 1/10th of display resolution per second.
# E.g. a value of 20 means: move at a speed of two display sizes per second.
# To disable animations, leave this unset or set to a very large value.
animation_speed = 50

# Automatically center the focused window when switching focus with keyboard,
# i.e. 'window_focus_west' or 'window_focus_east'.
# auto_center = false

[bindings]
# Moves the focus between windows.
window_focus_west = ["cmd - h", "cmd - leftarrow"]
window_focus_east = ["cmd - l", "cmd - rightarrow"]
window_focus_north = ["cmd - k", "cmd - uparrow"]
window_focus_south = ["cmd - j", "cmd - downarrow"]

# Swaps windows in chosen direction.
window_swap_west = "alt - h"
window_swap_east = "alt - l"

# Jump to the left-most or right-most windows.
window_focus_first = "cmd + shift - h"
window_focus_last = "cmd + shift - l"

# Move the current window into the left-most or right-most positions.
window_swap_first = "alt + shift - h"
window_swap_last = "alt + shift - l"

# Centers the current window on screen.
window_center = "alt - c"

# Cycles between the window sizes defined in the `preset_column_widths` option.
window_resize = "alt - r"

# Toggle full width for the current focused window.
window_fullwidth = "alt - f"

# Toggles the window for management. If unmanaged, the window will be "floating".
window_manage = "ctrl + alt - t"

# Stacks and unstacks a window into the left column. Each window gets a 1/N of the height.
window_stack = "alt - ]"
window_unstack = "alt + shift - ]"

# Moves currently focused window to the next display.
window_nextdisplay = "alt + shift - n"

# Moves the mouse pointer to the next display.
mouse_nextdisplay = "alt - n"

# Size stacked windows in the column to equal heights.
window_equalize = "alt + shift - e"

# Quits the window manager.
quit = "ctrl + alt - q"

# Window properties, matched by a RegExp title string.
[windows]

[windows.pip]
# Title RegExp pattern is required.
title = "Picture.*(in)?.*[Pp]icture"
# Do not manage this window, e.g. it will be floating.
floating = true

[windows.neovide]
# Matches an editor and always inserts its window at index 1.
title = ".*"
bundle_id = "com.neovide.neovide"
index = 1

[windows.popup]
# Matches a popup and silently appends it at the end.
title = "Unimportant popup window"
dont_focus = true
index = 100

[windows.all]
# Matches all windows and adds a few pixels of spacing to their borders.
title = ".*"
horizontal_padding = 4
vertical_padding = 2

Paste this into your terminal to create a default configuration file:

$ cat > ~/.paneru <<EOF

# ... paste the above configuration here ...

EOF

Live Reloading: Configuration changes made to your ~/.paneru file are automatically reloaded while Paneru is running. This is extremely useful for tweaking keyboard bindings and other settings without restarting the application. The settings can be changed while Paneru is running - they will be automatically reloaded.

Running as a service

$ paneru install
$ paneru start

Running in the foreground

$ paneru

Future Enhancements

• More commands for manipulating windows: fullscreen, finegrained size adjustments, etc.
• Scriptability. A nice feature would be to use Lua for configuration and simple scripting, like triggering and positioning specific windows or applications.

Communication

There is a public Matrix room #paneru:matrix.org. Join and ask any questions.

Architecture Overview

Paneru's architecture is built around the Bevy ECS (Entity Component System), which manages the window manager's state as a collection of entities (displays, workspaces, applications, and windows) and components.

The system is decoupled into three primary layers:

1. Platform Layer (src/platform/): Directly interfaces with macOS via objc2 and Core Graphics. It runs the native Cocoa event loop and pumps OS events into a channel consumed by Bevy.
2. Management Layer (src/manager/): Defines OS-agnostic traits (WindowManagerApi, WindowApi) that abstract window manipulation. The macOS-specific implementations (WindowManagerOS, WindowOS) bridge these traits to the Accessibility and SkyLight APIs.
3. ECS Layer (src/ecs/): The "brain" of the application. Bevy systems process incoming events, handle input triggers, and manage animations.

Repository Structure

• main branch: Contains the stable, released code.
• testing branch: Used for experimental features and architectural refactors. This branch is volatile and may be force-pushed.

Tile Scrollably Elsewhere

Here are some other projects which implement a similar workflow:

• Niri: a scrollable tiling Wayland compositor.
• PaperWM: scrollable tiling on top of GNOME Shell.
• karousel: scrollable tiling on top of KDE.
• papersway: scrollable tiling on top of sway/i3.
• hyprscroller and hyprslidr: scrollable tiling on top of Hyprland.
• PaperWM.spoon: scrollable tiling on top of MacOS.