linux-wallpaperengine Daemon

This project is still working in progress...

linux-wallpaperengine is an awesome project that provides Wallpaper Engine functionality on linux.
However, that project is more like implementation of the "core", which means there are no playlist support, etc.

This project aims to provide a daemon that runs in the background and summons linux-wallpaperengine periodically according to a "playlist" file.

Playlist file

The playlist file is a plain text file that records what wallpaper to show, in what ways and for how long.
Playlist files usually resides in $XDG_CONFIG_HOME/lxwengd or $HOME/.config/lxwengd and have the extension .playlist.
If both "" and ".playlist" are found in the search path, the program prefers .playlist.

# may be used to comment in the file. Empty lines will be ignored.

In the beginning of the file, you may use this command:

monitor <monitor id>

to indicate which monitor this playlist is going to be displayed on.
If you didn't indicate this, the wallpapers will be displayed in a window.

Define a wallpaper in this format:

<wallpaper id> [duration] [property1=value] [property2=value] ...

<wallpaper id> must be specified, which is exactly what you will specify as in linux-wallpaperengine's cmdline. View this id from Steam Workshop URL or anywhere you wish.

[duration] indicates how long this wallpaper should be displayed. Plain numbers will be treated as seconds, you may also use a value plus an unit such as 15m, 1h. If duration is not specified, it is equivalent as forever, which displays the wallpaper until the daemon quits.
Note that forever does not necessarily means the end of playlist, if the child process failed or is killed externally due to OOM or else, the daemon can still progress forwards, generating an "engine died" warning instead.

A list of properties may be passed using key=value pairs.
These properties are passed linux-wallpaperengine as arguments.
Here's a list of general properties:

• audio=[true | false], corresponding to --no-audio-processing in linux-wallpaperengine.
• volume=[volume], corresponding to --volume.
• automute=[true | false], corresponding to --automute.
• window=[geometry], corresponding to --window.
• fps=[max fps], corresponding to --fps.
• fullscreen-pause=[true | false], corresponding to --no-fullscreen-pause.
• mouse=[true | false], corresponding to --disable-mouse.
• scaling=[stretch | fit | fill | default], corresponding to --scaling.
• clamping=[clamp | border | repeat], corresponding to --clamping.

Also, see linux-wallpaperengine --list-properties <wallpaper id> for a list of other properties specific to wallpapers.
Note that neither general properties nor specific properties have their value checked!. So if you passed invalid values, LxWEngD will simply pass them as-is to linux-wallpaperengine, by which you will likely receive an "engine died" warning.

default command may be used to set up default properties of wallpapers.

default [property1=value] [property2=value] ...

Each default will clear previously defined default properties, so you cannot write

default a=b 
default c=d

instead of default a=b c=d.

There are also some other commands to use in the file:

• wait <duration> pauses the daemon's activity for the given duration. Note that when the daemon is displaying a wallpaper, it will not execute the next command until the end of the current display time ends. So use this when you want some space between wallpapers where linux-wallpaperengine will not be running.
• end makes the daemon quit immediately. It's possible to write lines after end, if you feel boring.
• loop makes the daemon go back to the beginning of the playlist file and do it over again and again. It's a short form of goto 1 0.
• goto <location> [times] jumps to a specific line of the playlist and executes the command on that line. <location> of course is the line number starting from 1. [times] indicates how many times this goto sentence may have effect, so goto 0 1 makes the playlist play over again, but will not go back again because of this goto, 0 indicates this goto sentence have permanent effect.
• replace <playlist file> changes the playlist the daemon is currently playing, starting from line 1 of the given playlist. If the given playlist cannot be found, then this line will be similar to end.
• summon <playlist file> is similar to replace, but instead of changing the playlist, it opens a new thread running the indicated playlist. So if the given playlist failed or quitted, the original thread is unaffected.
• monitor <monitor id> is as stated above, changes the monitor the playlist will be displayed on.
• default [property=value]... is described above.

If any command contains invalid value, or has bad syntax, the daemon will skip that line and generate a warning only.
If linux-wallpaperengine reports an error, the daemon will forward the error and jump to the next command. Because of this, the result of --dry-run only reflects the optimal situation, since killing the linux-wallpaperengine subprocess externally will also trigger this.

TODO: Probably code a lxwengctl to validate syntax

When the daemon reaches the end of the playlist file, it by default returns to the beginning as if there's a loop.

Usage

You must have a working installation of linux-wallpaperengine on your system.
If the linux-wallpaperengine command is not in your $PATH, you should use the --binary argument to identify the path to the binary.

$ lxwengd
    [-p | --playlist playlist name]
    [-a | --assets-path path to Wallpaper Engine assets]
    [-b | --binary path to linux-wallpaperengine]
    [--dry-run]
    [--help]
    [--version]

The daemon by default searches for playlist files in $XDG_CONFIG_HOME/lxwengd or $HOME/.config/lxwengd.
For other files not in the default search path, you may use the full path with the --playlist argument.

It expects playlist files to have the extension .playlist, for which case you can just use the filename without extension. For any other extensions, use the full filename with extension.
When invoked with no arguments, it searches for default.playlist and will fail if it didn't find any.

Troubleshooting

Any issues, feature requests or pull requests are welcomed!

Despite its name, LxWEngd does not handle any graphical work on its own, it merely calls linux-wallpaperengine in the background.

If you encounter such issues, you may use the --dry-run flag and extract the command LxWEngd executed on the problematic wallpaper and report to linux-wallpaperengine.

Also, it does not check whether there's another wallpaper daemon running, even another instance of itself. This may occur when you wrote many playlists to run simultaneously but there's a clash between wallpapers or you forgot to set the monitor property correctly. If there are many wallpapers running simultaneously, the situation will be dependent to you window manager or anything similar...

linux-wallpaperengine is missing assets (CAssetLoadException)

This may happen if your Steam installation (or anything that contains the assets directory linux-wallpaperengine requires) is not standard.
You might need to pass the path to the assets directory explicitly.

High CPU usage after a wallpaper is displayed for a while

LxWEngD does not handle any graphics on its own, so you are likely encountering an issue with linux-wallpaperengine.
However, you can try to "split" the duration into some shorter segments. For example, to display a wallpaper for 1 hour, instead display it 4 times continously for 15 minutes. Since this would involve a restart of linux-wallpaperengine, CPU and memory will be released and give some breathing time to your computer.