XDG デスクトップ ポータル
- Portals は、アプリケーションのサンドボックスの外部から安全にリソースにアクセスするためのフレームワークです。それらは、ネットワークのステータスを決定する、ファイルチューザーでファイルを開く、URIを開く、スクリーンショットやスクリーンキャストを取るなど、アプリケーションに一連の共通機能を提供します [...]
Portals は Flatpak を通じてサンドボックス化されたアプリケーションで使用するために設計されましたが、任意のアプリケーションは Portals を使用して、デスクトップやツールキットに関係なく特徴に均一なアクセスを提供できます。これは一般的に、例えば、 PipeWire 経由で Wayland にスクリーン共有を許可するためや、現在の デスクトップ環境 と同じツールキットを使用する Firefox 上でファイルの開くと保存のダイアログを使用するために使用されます。
目次
インストール
xdg-desktop-portal と一つ以上のバックエンドをインストールします。パッケージには、D-Bus を通じて自動的に起動される systemd/ユーザー サービスが含まれています。
Backends
When an application makes a request through a portal, it is handled by xdg-desktop-portal, which then forwards it to a backend implementation. This allows a clean way to provide suitable user interfaces that fit into different desktop environments, and access environment-specific APIs for requests like showing notifications or recording the screen.
Multiple backends can be installed, and they are located in /usr/share/xdg-desktop-portal/portals/*.portal. Each portal backend file contains a list of interfaces that it can handle, and the desktop environments that it can be used in. When a request is made, xdg-desktop-portal will use the XDG_CURRENT_DESKTOP environment variable to determine which backend it will use for the request. If more than one backend can be used for the current desktop, the first one in alphabetical order is chosen. If no backend for the current desktop can handle the interface, no backend is available for the current desktop, or xdg-desktop-portal can't determine the current desktop, then it will choose the first portal in alphabetical order between all of the installed portals that support the requested interface.
For example, a Sway user may use xdg-desktop-portal-wlr for screen sharing support and xdg-desktop-portal-gtk as a fallback for all other interfaces that xdg-desktop-portal-wlr does not implement.
List of backends and interfaces
The following table lists all backends available and their support for certain common interfaces.
| Backend | File chooser | Screenshot and screen cast |
|---|---|---|
| xdg-desktop-portal-gnome | Yes | Yes, on GNOME |
| xdg-desktop-portal-gtk | Yes | No |
| xdg-desktop-portal-kde | Yes | Yes, on KDE |
| xdg-desktop-portal-hyprland1 | No | Yes, on wlroots |
| xdg-desktop-portal-lxqt | Yes | No |
| xdg-desktop-portal-wlr | No | Yes, on wlroots |
| xdg-desktop-portal-liri-gitAUR | Yes | Yes, on Liri |
| xdg-desktop-portal-shanaAUR | Yes2 | No |
| xdg-desktop-portal-tdAUR | Yes | No |
| xdg-desktop-portal-termfilechooser-gitAUR | Yes3 | No |
- works with all wlroots-based compositors, but provides extra functionality when used with Hyprland such as sharing individual windows.
- redirects requests to GNOME/GTK/KDE/LXQt backends
- allows using a terminal file manager as a file chooser
Troubleshooting
xdg-desktop-portal-wlr does not start automatically on sway
For xdg-desktop-portal-wlr to work, the XDG_CURRENT_DESKTOP and WAYLAND_DISPLAY environment variables have to be set in the systemd user session. XDG_CURRENT_DESKTOP has to be set to the name of your compositor, e.g. XDG_CURRENT_DESKTOP=sway. WAYLAND_DISPLAY is set automatically by the compositor.
Check whether these variables are set with systemctl --user show-environment. If they are not set, import these environment variables into the systemd user session and dbus by running the following commands after launching the compositor (e.g., include them in the compositor's configuration file).
$ systemctl --user import-environment WAYLAND_DISPLAY XDG_CURRENT_DESKTOP $ dbus-update-activation-environment --systemd WAYLAND_DISPLAY XDG_CURRENT_DESKTOP=compositor_name
See [1] and [2] for more details.
Using multiple monitors with xdg-desktop-portal-wlr
xdg-desktop-portal-wlr requires an external chooser to select the shared monitor. By default, it looks for slurp, wofi and bemenu in this order. When using slurp, after a request for screen sharing you will be presented with a crosshair cursor and you will need to click the screen you want to share. When using wofi or bemenu, you will be presented with a menu of available displays to share. If no choosers are available, xdg-desktop-portal-wlr will fallback to the first monitor found. For more information, see xdg-desktop-portal-wlr(5) § SCREENCAST OPTIONS.
See also
- Portal Documentation: Lists all APIs applications and backends can implement.