randpaper-0.1.5 is not a library.

randpaper - A high-performance wallpaper & theme daemon for Wayland

randpaper is a lightweight Rust utility designed for efficiency. It manages per-monitor wallpaper rotation and optional system-wide theme synchronization—replacing complex script chains with a single, optimized binary.

🚀 Features

⚡ Performance: Written in Rust using tokio. Scans your image directory once into memory (caching paths) to prevent disk I/O spikes, even with massive wallpaper collections.
🎨 Dynamic Theming: Automatically extracts dominant colors from the current wallpaper and generates config files for Ghostty, Kitty, and Foot, keeping your terminal in sync with your desktop.
- 🫟 Waybar Theming: Generates CSS variables based on the image palette. and reloads Waybar when it changes wallpapers applying the theming automatically.
🖥️ Multi-Monitor: Assigns a unique random image to every active output simultaneously.
🔄 Dual Operating Modes: Run as a background daemon with automatic cycling, or use one-shot mode for manual wallpaper changes.
🛠️ Modular Backends: Works seamlessly with Sway and Hyprland (via Sway IPC or hyprctl) and supports both swaybg and swww renderers.
Support for both swww and its replacement awww.

🛠 Installation

Prerequisites

You need swaybg or (swww / awww) installed as the renderer.

# From source
cargo install --git https://github.com/saylesss88/randpaper
# crates.io
cargo install randpaper

Add as a flake input:

inputs = {
  randpaper.url = "github:saylesss88/randpaper";
};

Install in environment.systemPackages or home.packages:

environment.systemPackages = {
  inputs.randpaper.packages.${pkgs.stdenv.hostPlatform.system}.default
};

Pass inputs through specialArgs in your flake.nix

And add an exec for either hyprland or sway, only for randpaper:

Hyprland Example:

wayland.windowManager.hyprland = {
  settings = {
    exec-once = [
  # Standard Usage
  "randpaper --time 15m /home/your-user/Pictures/wallpapers --backend hyprland --renderer swww"
  # UWSM Usage w/ swaybg
  "uwsm app -- randpaper --time 15m /home/your-user/Pictures/wallpapers --backend hyprland --renderer swaybg"
    ];
  };
}

Sway Example:

wayland.windowManager.sway = {
  extraConfig = ''
    # Default backend is Sway
     exec randpaper --time 30m /home/your-user/wallpapers
  '';
};

Note: randpaper manages the renderer process for you. You do not need separate exec-once = swaybg ... or exec-once = swww ... lines in your config.

🧾 Usage

Daemon Mode (Background Process)

With swww or awww installed you can test which mode you want from the command line before adding an exec-once for randpaper to your configuration:

When you provide the --time flag, randpaper runs as a daemon and automatically cycles wallpapers at the specified interval:

# Change every 5 minutes using Hyprland + swww transitions
randpaper --time 5m --backend hyprland --renderer swww ~/Pictures/wallpapers

# Change every hour with custom transitions
randpaper --time 1h --renderer swww --transition-type fade ~/Pictures/wallpapers

These commands work without swww-daemon running because randpaper automatically launches a swww-daemon process if one isn't already running.

One-Shot Mode (Pick Once & Exit)

Without the --time flag, randpaper picks a random wallpaper, updates themes, and exits immediately.

It's recommended to run one-shot via a compositor keybind so it inherits the correct session/IPC environment.(i.e., running randpaper ~/Pictures/wallpapersfrom the command line doesn't work as expected)

# Sway: cycle wallpaper + themes now (one-shot)
bindsym $mod+Shift+n exec randpaper ~/Pictures/wallpapers

# Hyprland: cycle wallpaper + themes (one-shot)
"$mod SHIFT,N,exec, randpaper --backend hyprland /home/jr/Pictures/wallpapers2"

swaybg can't be one-shot from the command line because it's not a set-and-exit command; it's a long-running wallpaper service.

Use cases for one-shot mode:

Manual wallpaper changes via keybinds
Scripted theme updates
Testing without running a daemon

swww/awww Transitions:

# Use fade transitions
randpaper --renderer swww --transition-type fade --transition-step 90 --transition-fps 60 ~/Pictures/wallpapers

# Use wipe transitions for hyprland
randpaper --renderer swww --transition-type wipe --transition-step 90 --transition-fps 60 ~/Pictures/wallpapers --backend hyprland

Again, the above commands only work if there isn't already a swww-daemon instance running. Adding an exec randpaper to your config automatically adds an exec swww-daemon
Sample wallpaper repo

Advanced Options

Flag	Description	Default
`[DIR]`	Directory containing images	`.`
`-t, --time`	Time between changes(e.g., 15m, 1h)	`30m`
`-b, --backend`	Detection backend: `sway` or `hyprland`	`sway`
`-o, --outputs`	Specific outputs to target (Sway only)	Auto-discover
`-r, --renderer`	Renderer tool: `swaybg` or `swww`	`swaybg`
`--transition-type`	swww transition: `fade`, `wipe`, `outer`	`simple`
`-s, --transition-step`	swww transition step (0-100)	`90`
`-f, --transition-fps`	swww target frame rate for transitions	`30`

--transition-type: Choose between (simple, fade, wipe, outer, inner, random)

NOTE: All transition options are ignored when using --renderer swaybg.

🎨 Automatic Terminal Theming

randpaper automatically extracts a 16-color palette from your wallpaper and generates theme files in ~/.config/randpaper/themes/.

To use them, add the include line to your terminal config:

Ghostty

File: ~/.config/ghostty/config

config-file = ~/.config/randpaper/themes/ghostty.config

Foot

File: ~/.config/foot/foot.ini (Place near end of file)

[main]
include=~/.config/randpaper/themes/foot.ini

Kitty

File: ~/.config/kitty/kitty.conf

include ~/.config/randpaper/themes/kitty.conf

Live-Reload of Terminal Themes

Ghostty: live reload works with either "cycle" keybind (i.e., theme updates immediately with either pkill -USR1 randpaper from either a keybind or the command line or a keybind set to exec randpaper ~/Pictures/wallpapers)(Tested on Fedora with Sway, expect different behavior on NixOS)
Foot / Kitty: the theme file is updated, but existing windows may not live-reload reliably; close and reopen the terminal to pick up the new theme. (Work in Progress)

# home.nix or ghostty.nix
programs.ghostty = {
  enable = true;
  settings = {
    # The '?' makes the include optional/non-blocking
    "config-file" = "?~/.config/randpaper/themes/ghostty.config";
  };
};

On boot up, the generated theme will be applied.
Run the cycle command then type pkill -USR2 ghostty to apply the theme instantly.

🫟 Waybar Dynamic Theming (Optional)

To use randpaper with a waybar setup, ensure you call the daemon via exec waybar in your Sway or Hyprland config.

(Sway Example ~/.config/sway/config):

exec randpaper --time 10m ~/Pictures/wallpapers

bar {
    swaybar_command waybar
}
# ---snip---

randpaper automatically generates a Waybar CSS color file from the current wallpaper palette and writes it to:

~/.config/randpaper/themes/waybar.css

This file only defines color variables (it doesn't change your bar by itself). To use it, you import it from your Waybar style.css and then reference the variables in your existing rules.

Example of the generated waybar.css file:

/* auto-generated by randpaper */
@define-color rp_bg #1c1c24;
@define-color rp_fg #e4dcd4;
@define-color rp_accent #f394a4;
@define-color rp_warn #201c24;
@define-color rp_ok #201c24;
@define-color rp_border #f394a4;
@define-color rp_muted #1c1c24;

Import the generated file

At the very top of your Waybar style.css (Change YOUR_USER to your username):

@import "/home/YOUR_USER/.config/randpaper/themes/waybar.css";

Use the variables in your CSS

Replace hard-coded colors with variables like @rp_bg, @rp_fg, @rp_accent, etc.

Example:

window#waybar {
  background-color: alpha(@rp_bg, 0.8);
  color: @rp_fg;
}

#workspaces button.focused {
  background-color: @rp_accent;
  color: @rp_bg;
}

Full style.css Example

randpaper automatically reloads Waybar when it changes wallpapers, keeping your bar perfectly themed without manual intervention. (SIGUSR2 zero-flicker reload)

Obviously, the more hard-coded colors you replace with the dynamically generated CSS variables the more noticeable it will be.

NOTE: Just adding the @import at the top makes the variables available, you need to reference them for the changes to be applied.

NixOS Waybar Example
On NixOS, after cycling with one-shot run pkill -USR2 waybar to apply the new theme.

⏭️ Cycling Wallpapers & Themes

Manual Wallpaper Change (Recommended)

The simplest way to instantly change wallpapers is to run one-shot mode while the randpaper daemon is running:

Hyprland Config:

bind = $mainMod SHIFT, N, exec, randpaper ~/Pictures/wallpapers --backend hyprland

Sway Config:

bindsym $mod+Shift+n exec randpaper ~/Pictures/wallpapers

This picks a new wallpaper, updates all themes (terminal + Waybar), and exits. Your background daemon continues running for automatic cycles.

Signal Running Daemon (Alternative for Standare Filesystem Hierarchy layouts)

You can also force the daemon to cycle immediately without spawning a separate process:

Sway Config:

bindsym $mod+n exec pkill -USR1 randpaper

Hyprland Config:

bind = $mainMod SHIFT, N, exec, pkill -USR1 randpaper

Shell:

pkill -USR1 randpaper

Now when you run the above keybind, you will get a new wallpaper, terminal theme, and waybar theme.

NOTE: Expect different behavior on NixOS.

⚙️ How it Works

Startup: Caches all valid image paths (jpg, png, bmp, webp) from the target directory into memory.

2 Loop(daemon mode): Every interval (e.g., 30m):

Queries active monitors via IPC.
Picks a random image for the primary monitor and extracts its color palette.
Generates theme files and triggers terminal reloads.
Spawns a non-blocking background process (swaybg daemon or swww client) to update the display.
Sleeps efficiently until the next cycle.

One-Shot (no --time): Picks wallpaper, updates themes, exits immediately.

Works reliably as a keybind, may have to close out terminal and relaunch for the new theme to be applied.

License

Apache License 2.0

randpaper 0.1.5