Does not work when using windowtolayer with ghostty

[Anomalocaridid]

I am trying to use windowtolayer to make a ghostty terminal window swaylock-plugin's background.

swaylock-plugin --command-each 'windowtolayer -- ghostty -e asciiquarium' does not work, resulting in only a solid light grey background.

Using alacritty instead, like in swaylock-plugin --command-each 'windowtolayer -- alacritty -e asciiquarium', works as expected, with the terminal window running asciiquarium visible in the background .

Also, just running windowtolayer -- ghostty -e asciiquarium without swaylock-plugin works as expected, running the terminal as a desktop background.

When running swaylock-plugin --command-each 'windowtolayer -- ghostty -e asciiquarium' in a terminal, I get the following output repeated over and over (but with different process numbers and timestamps, of course):

(process:97897): Gdk-WARNING **: 16:25:45.497: The Wayland compositor does not provide one or more of the required interfaces, not using Wayland display
Downstream hang up

(process:97897): Gtk-WARNING **: 16:25:45.497: Failed to open display
Forked background plugin (pid = 97904): windowtolayer -- ghostty -e asciiquarium
info: ghostty version=1.0.1
info: ghostty build optimize=ReleaseFast
info: runtime=apprt.Runtime.gtk
info: font_backend=font.main.Backend.fontconfig_freetype
info: dependency harfbuzz=10.1.0
info: dependency fontconfig=21500
info: renderer=renderer.OpenGL
info: libxev backend=main.Backend.io_uring
info(os): setlocale from env result=en_US.UTF-8
info(gtk): GTK version build=4.16.3 runtime=4.16.3
info: reading configuration file path=/home/anomalocaris/.config/ghostty/config
info(config): default shell source=env value=/run/current-system/sw/bin/fish
info(sentry): sentry envelope does not contain crash, discarding

The last repetition also includes the following line:

2025-01-24 16:25:51 - [main.c:1892] Client failed to redraw output 51 in time; falling back to a client-less mode

Edit: Also, I am currently using the latest commit of both swaylock-plugin and windowtolayer.

[mstoeckl]

The key error message is (process:97897): Gdk-WARNING **: 16:25:45.497: The Wayland compositor does not provide one or more of the required interfaces, not using Wayland display. This error comes from Gtk4, specifically from gdkdisplay-wayland.c; it looks like Gtk4 requires the Wayland interface wl_data_device_manager, which the nested Wayland compositor in swaylock-plugin does not provide. (It currently only implements wl_compositor, wl_shm, zwlr_layer_shell_v1, zxdg_output_manager_v1, zwp_linux_dmabuf_v1, wp_fractional_scale_manager_v1, wp_viewporter, and wl_output; interfaces which are useful for wallpaper programs. wl_data_device_manager is used for copy-paste operations, which wallpapers usually do not need. windowtolayer should pass through all interfaces except zwlr_layer_shell_v1/xdg_wm_base unmodified.)

Alacritty and most other terminals should work because they do not require wl_data_device_manager to run. (The only other terminal of which I am aware, which does not currently work with windowtolayer + swaylock-plugin, is foot, which requires wl_subcompositor to (if I recall correctly) more efficiently implement scrolling.)

I'll see if I can modify swaylock-plugin to provide wl_data_device_manager; until that is done, I'd recommend using a different terminal with swaylock-plugin.

[mstoeckl]

I've implemented wl_data_device_manager in 7df380e, which should make windowtolayer -- ghostty -e asciiquarium work.

[Anomalocaridid]

Indeed, it does. Thank you!