uscreen

UScreen is an open-source alternative to SuperDisplay for Linux hosts. It turns an Android 8.1+ tablet into a genuine extended USB display and a pressure-sensitive graphics tablet, using a direct ADB-over-USB connection rather than Wi-Fi, USB tethering, a dummy HDMI plug or a cloud account. Screen and input data stay on the cable. Core capabilities described in the README: - Real extended display: a virtual display is created through the EVDI kernel module, so the tablet appears in the system display settings and windows can be moved onto it, rather than being mirrored. - Pen input: pressure, tilt, eraser and stylus button are exposed to Linux as a graphics-tablet device, so applications such as Krita, GIMP and Blender see a tablet. A one-tap graphics-tablet mode uses the pen on the host's own screen with no display latency. - Latency: the project publishes measured figures of roughly 22 ms median end-to-end over USB with H.264 and 15-18 ms with HEVC on its reference hardware, with method and limitations documented. - Plug-and-play: a user daemon starts with the desktop, finds the tablet over adb, launches the Android app and sizes the display to the tablet panel. - Privacy: loopback-only ports guarded by a per-session token, no telemetry and no account; the only outbound request is an optional version check against GitHub, which can be disabled. Installation is packaged for several distribution families: .deb for Debian/Ubuntu/Mint/Pop, RPM for openSUSE and Fedora, PKGBUILD for Arch, and a tarball installer for Bazzite, Nobara and others. The tablet side is an APK with USB debugging enabled. A `uscreen doctor` command diagnoses setup problems. Compatibility notes: the reference setup is Bazzite with KDE Plasma 6 on Wayland and an NVIDIA GPU paired with a Galaxy Tab S9 Ultra; Arch Linux KDE Plasma Wayland and Fedora 44 KDE Plasma with a Galaxy Tab S9 FE are reported as working by external users. Debian, Fedora and openSUSE packages were container-tested without a tablet. GNOME and X11 reportedly get the display and stream but require manual input mapping. Configuration lives in `~/.config/uscreen/config.toml` and is reachable from a GUI, the tablet app's settings sheet, a tray icon or CLI flags. Options include display position (right, left, above, below), orientation handling, codec choice (h264_nvenc default, hevc_nvenc, 10-bit HEVC Main10 for gradient banding), stream scaling, support for up to four tablets, and an optional Wi-Fi fallback that prefers the cable when both are available. The README also compares UScreen with SuperDisplay, Weylus, Sunshine + Moonlight, spacedesk, MoreSpace, TethrLink and subdisplay, and lists a roadmap: AOA transport to remove the USB-debugging requirement, input mapping on GNOME and X11, and a PipeWire/dmabuf capture path. HDR is explored but blocked by EVDI's 8-bit framebuffers; iPad support is considered but not scheduled. The project is MIT-licensed, with a bundled LGPL-2.1 libevdi client library from DisplayLink.