backdrop

Set a new desktop wallpaper every day from various sources.

What it does

backdrop fetches a daily image from one of several curated sources and sets it as your desktop wallpaper. It automatically picks the best display mode based on the image dimensions and your screen aspect ratio.

Run it manually or let a systemd timer handle it on a schedule.

Quick Install

curl -fsSL https://ensl.ee/backdrop | bash

Requirements

• A supported Linux desktop environment (see below)
• curl, python3 (standard on most distros)
• systemd (for the daily timer)

Desktop Environments

backdrop supports the following Desktop Environments.

Desktop	Method	Notes
GNOME	gsettings
KDE Plasma	qdbus6 or qdbus	Sets the wallpaper and fill mode on all desktops
KDE Plasma (fallback)	plasma-apply-wallpaperimage	Used if qdbus is unavailable; requires Plasma 5.21+, fill mode not configurable
Xfce	xfconf-query	Sets wallpaper and fill mode on all monitors; open Display settings once first
Cinnamon	gsettings
MATE	gsettings
LXQt	pcmanfm-qt
COSMIC	config file	Writes ~/.config/cosmic/com.system76.CosmicBackground/v1/all (RON format)
Other	gsettings or qdbus	Tries gsettings first, then qdbus; set XDG_CURRENT_DESKTOP if detection fails

Installation

Use the quick install script or clone the repo and run the installer locally:

git clone https://github.com/aensley/backdrop.git \
  && cd backdrop/src && ./install.sh

The installer:

1. Downloads (or uses local) backdrop.sh
2. Copies backdrop to /usr/local/bin/
3. Runs backdrop enable, which downloads and installs the systemd unit files and starts the daily timer

Additional users

With backdrop already installed, additional users can enable it for their login with:

backdrop enable

This will download the matching systemd unit files from the matching GitHub release and install them into their own ~/.config/systemd/user/ directory.

Usage

backdrop <command>

Command	Description
status	Show version, active source, last image, and image metadata (default)
update [--force]	Refresh wallpaper from the active source
set <source...> [--force]	Switch active source(s) and refresh now; use all for all sources
set-time <HH:MM>	Set the daily run time (24-hour); restarts timer if active
set-rotate-interval <minutes>	Set rotation interval in minutes; 0 to disable
random [--force]	Refresh from a randomly chosen source (does not change active)
enable	Enable the systemd --user timer; downloads unit files from GitHub if missing
disable	Disable the systemd --user timer
upgrade	Check for and install the latest version from GitHub
uninstall	Remove backdrop from this system
help	Show help

Sources

One, multiple, or all sources can be active simultaneously.

Key	Name
bing	Bing Image of the Day https://www.bing.com/
earth	Earth.com Image of the Day https://www.earth.com/gallery/images-of-the-day/
apod	NASA Astronomy Picture of the Day https://apod.nasa.gov/apod/
eo	NASA Earth Observatory Image of the Day https://science.nasa.gov/earth/earth-observatory/image-of-the-day/
iotd	NASA Image of the Day (default) https://www.nasa.gov/image-of-the-day/
natgeo	National Geographic Photo of the Day https://www.nationalgeographic.com/photo-of-the-day/
wmc	Wikimedia Commons Picture of the Day https://commons.wikimedia.org/wiki/Commons:Picture_of_the_day

Switch to a single source at any time:

backdrop set apod

Or enable multiple sources to rotate between them:

# Enable two or more specific sources
backdrop set iotd apod bing

To enable all sources:

# Enable all sources
backdrop set all

The wallpaper updates immediately when you run set, and the active source is reflected in backdrop status.

Rotation

With multiple sources enabled, you can rotate between them at a fixed interval. When you set multiple sources, rotation is automatically enabled at 30 minutes:

# Rotate between three sources every 30 minutes (auto-set default)
backdrop set iotd apod bing

# Rotate through all sources
backdrop set all

# Change the rotation interval (e.g. every 2 hours)
backdrop set-rotate-interval 120

# Disable rotation and go back to a single source
backdrop set iotd

When rotation is active, the systemd timer fires at the rotation interval instead of the daily time set by set-time. The active source is determined by a time-slot calculation: slot = (current_minute / interval) % num_sources, so the same source is always shown for the full duration of its slot.

Configuration

The config file lives at ~/.config/backdrop/config and is created on first run. You can edit it directly or use the set / set-time commands.

Key	Default	Description
source	iotd	Active wallpaper source(s); space-separated list or all
rotate_interval	0	Minutes between source rotations; 0 to disable (uses timer_time for daily updates instead)
screen_aspect_ratio	1.7778	Fallback aspect ratio if auto-detect fails (16:9=1.7778, 16:10=1.6, 21:9=2.3333, 4:3=1.3333)
zoom_min_coverage	0.55	Crop tolerance: if zoom-filling would keep less than this fraction of the image visible, use scaled mode instead
user_agent	backdrop/1.0 (...)	HTTP User-Agent sent with all requests
timer_time	08:00	Time of day to run the daily update (24-hour HH:MM); only applies when rotate_interval = 0

Uninstallation

backdrop uninstall

To also remove your config and cached wallpapers:

backdrop uninstall --purge