feat(linux): add full Linux support

.github/workflows/build-linux.yml

@@ -0,0 +1,111 @@
+name: Build Linux
+
+# Runs only on a `linux-*` tag (e.g. `git tag linux-1 && git push origin linux-1`)
+# or a manual dispatch -- never on every commit, and separate from the `v*`
+# release tags so it won't trigger the macOS Release workflow. Produces a
+# downloadable artifact (no GitHub release).
+on:
+    push:
+        tags:
+            - 'linux-*'
+    workflow_dispatch:
+
+permissions:
+    contents: read
+    packages: read
+
+jobs:
+    build:
+        # ubuntu-22.04 = oldest base shipping WebKitGTK 4.1, so glibc stays 2.35
+        # for broad AppImage compatibility (newer bases raise the glibc floor).
+        runs-on: ubuntu-22.04
+        steps:
+            - name: Checkout
+              uses: actions/checkout@v4
+
+            - name: Setup Bun
+              uses: oven-sh/setup-bun@v2
+              with:
+                  bun-version: latest
+
+            - name: Setup Rust toolchain
+              uses: dtolnay/rust-toolchain@stable
+
+            - name: Cache cargo build
+              uses: Swatinem/rust-cache@v2
+              with:
+                  workspaces: src-tauri
+
+            - name: Install Linux system deps
+              # 22.04 ships libpipewire 0.3.48, too old for the libspa crate
+              # (spa_video_info_raw.flags). The upstream PPA backports a current
+              # libpipewire while keeping the glibc 2.35 base.
+              run: |
+                  sudo add-apt-repository -y ppa:pipewire-debian/pipewire-upstream
+                  sudo apt-get update
+                  sudo apt-get install -y --no-install-recommends \
+                    libwebkit2gtk-4.1-dev libjavascriptcoregtk-4.1-dev \
+                    libgtk-3-dev librsvg2-dev librsvg2-bin libgtk-3-bin \
+                    libayatana-appindicator3-dev libsoup-3.0-dev libssl-dev \
+                    libpipewire-0.3-dev clang libclang-dev \
+                    libasound2-dev libopus-dev \
+                    desktop-file-utils xdg-utils patchelf rpm
+
+            - name: Install JS deps
+              run: bun install --frozen-lockfile
+
+            - name: Build AppImage + deb + rpm
+              uses: tauri-apps/tauri-action@v0
+              with:
+                  projectPath: src-tauri
+                  args: '--bundles appimage,deb,rpm -c {"bundle":{"createUpdaterArtifacts":false}}'
+
+            - name: Strip bundled host libs from AppImage
+              # linuxdeploy bundles host-integration libs that aren't on the
+              # AppImage excludelist. They then shadow the system copies and
+              # break against the host's plugin ecosystem:
+              #   - libwayland-* -> WebKit EGL init fails (EGL_BAD_PARAMETER /
+              #     blank window) against newer Mesa
+              #   - libpipewire/libspa -> can't load SPA plugins (support.system),
+              #     "pipewire: Creation failed", since the spa-0.2/ plugin dir
+              #     is not bundled
+              # Remove them so the app links the host's copies + their plugins.
+              run: |
+                  set -euxo pipefail
+                  export APPIMAGE_EXTRACT_AND_RUN=1
+                  app=$(find src-tauri/target/release/bundle/appimage -name '*.AppImage' | head -1)
+                  "$app" --appimage-extract
+                  rm -fv squashfs-root/usr/lib/libwayland-client.so* \
+                         squashfs-root/usr/lib/libwayland-egl.so* \
+                         squashfs-root/usr/lib/libwayland-cursor.so* \
+                         squashfs-root/usr/lib/libpipewire-0.3.so* \
+                         squashfs-root/usr/lib/libspa-0.2.so*
+                  curl -fsSL -o /tmp/appimagetool \
+                    https://github.com/AppImage/appimagetool/releases/download/continuous/appimagetool-x86_64.AppImage
+                  chmod +x /tmp/appimagetool
+                  rm -f "$app"
+                  ARCH=x86_64 /tmp/appimagetool squashfs-root "$app"
+                  rm -rf squashfs-root
+
+            # Separate artifacts so each downloads on its own -- grabbing the
+            # small deb/rpm doesn't pull the heavy AppImage.
+            - name: Upload AppImage
+              uses: actions/upload-artifact@v4
+              with:
+                  name: Splitwave-AppImage-x86_64
+                  path: src-tauri/target/release/bundle/appimage/*.AppImage
+                  if-no-files-found: error
+
+            - name: Upload deb
+              uses: actions/upload-artifact@v4
+              with:
+                  name: Splitwave-deb-x86_64
+                  path: src-tauri/target/release/bundle/deb/*.deb
+                  if-no-files-found: error
+
+            - name: Upload rpm
+              uses: actions/upload-artifact@v4
+              with:
+                  name: Splitwave-rpm-x86_64
+                  path: src-tauri/target/release/bundle/rpm/*.rpm
+                  if-no-files-found: error

README.md

@@ -1,12 +1,14 @@
 [![Downloads](https://img.shields.io/github/downloads/Horuse/Splitwave/total.svg)](https://github.com/Horuse/Splitwave/releases/latest)
 # Splitwave
-Splitwave is a node-based audio router for macOS. Wire microphones, system audio, per-app capture, and WAV files into a visual graph, run them through a chain of effects — EQ, compression, reverb, limiting, and more — then send the result to speakers or record it in WAV, FLAC, AIFF, MP3, Opus, or AAC.
+Splitwave is a node-based audio router for macOS and Linux. Wire microphones, system audio, per-app capture, and WAV files into a visual graph, run them through a chain of effects — EQ, compression, reverb, limiting, and more — then send the result to speakers or record it in WAV, FLAC, AIFF, MP3, Opus, or AAC.
 
 ![Splitwave preview](./preview.png)
 
 
 ## Installation
 
+### macOS
+
 Download the latest `.dmg` from [Releases](https://github.com/Horuse/Splitwave/releases/latest),
 open it, and drag Splitwave to Applications.
 
@@ -21,10 +23,19 @@ Then open Splitwave normally.
 
 **After each update, Screen Recording permission resets** (macOS revokes it when the binary changes and the app is unsigned). To re-grant it: open System Settings → Privacy & Security → Screen Recording, click **−** to remove Splitwave, then click **+** and add it back.
 
+### Linux
+
+Requires a PipeWire-based audio session (default on most current distros).
+Download the build for your system from [Releases](https://github.com/Horuse/Splitwave/releases/latest):
+
+- **AppImage** — `chmod +x Splitwave_*.AppImage && ./Splitwave_*.AppImage`
+- **`.deb`** (Debian/Ubuntu) — `sudo apt install ./Splitwave_*.deb`
+- **`.rpm`** (Fedora/RHEL/openSUSE) — `sudo rpm -i Splitwave-*.rpm`
+
 ## Features
 
-- **Inputs:** microphones, system audio, per-application audio
-  (ScreenCaptureKit), WAV files, virtual device loopback
+- **Inputs:** microphones, system audio, per-application audio, WAV files,
+  virtual device loopback
 - **Outputs:** physical speakers/interfaces, file recording in WAV (16/24-bit
   PCM + 32-float), FLAC, AIFF, Opus, MP3, AAC (M4A), virtual devices
 - **Effects:** Gain, Mute, Channel Balance, Saturator, 10-band Graphic EQ,
@@ -35,23 +46,40 @@ Then open Splitwave normally.
   Use them to capture loopback audio from any app or to feed processed audio into
   apps that accept a microphone input (DAWs, Discord, etc.)
 
+System and per-app capture use **ScreenCaptureKit** on macOS and **PipeWire** on
+Linux; virtual devices are AudioServerPlugin drivers on macOS and PipeWire
+null-sinks on Linux.
+
 ## Stack
 
 - **Frontend:** Svelte, Tauri, @xyflow/svelte
-- **Engine:** Rust -- `cpal` (device I/O), `rtrb` (SPSC ring buffers), `rubato`
-  (resampling), `hound` (WAV), `flac-codec`, `opus`, `mp3lame-encoder`,
-  `ebur128`
-- **macOS-specific:** custom Swift static library for ScreenCaptureKit,
-  compiled by `build.rs` via `swiftc`; CoreAudio HAL FFI for device
-  enumeration; libASPL-based AudioServerPlugin for virtual device driver
+- **Engine:** Rust -- `rtrb` (SPSC ring buffers), `rubato` (resampling),
+  `hound` (WAV), `flac-codec`, `opus`, `mp3lame-encoder`, `ebur128`
+- **macOS:** `cpal` device I/O; custom Swift static library for ScreenCaptureKit,
+  compiled by `build.rs` via `swiftc`; CoreAudio HAL FFI for device enumeration;
+  libASPL-based AudioServerPlugin for the virtual device driver
+- **Linux:** `pipewire` for device I/O, system/app capture, and virtual
+  null-sinks; `freedesktop-desktop-entry` / `freedesktop-icons` for app icons
 
 
 ## Development
 
 ### Prerequisites
 
+**macOS:**
+
 - macOS 13+ with Xcode Command Line Tools (`xcode-select --install`) -- gives
   you `swiftc` and the SDKs Tauri needs.
+
+**Linux:**
+
+- A PipeWire session and these dev packages (Debian/Ubuntu names):
+  `libwebkit2gtk-4.1-dev libgtk-3-dev librsvg2-dev libayatana-appindicator3-dev`
+  `libsoup-3.0-dev libpipewire-0.3-dev clang libclang-dev libasound2-dev`
+  `libopus-dev`
+
+**Both:**
+
 - [Rust](https://rustup.rs) (stable toolchain)
 - [Bun](https://bun.sh) (`curl -fsSL https://bun.sh/install | bash`)
 
@@ -65,28 +93,33 @@ bun run tauri dev
 ### Useful commands
 
 ```bash
-bun run check                      # svelte-check + tsc
-bun run generate                   # regenerate TypeScript types from Rust (ts-rs)
+bun run check                          # svelte-check + tsc
+bun run generate                       # regenerate TypeScript types from Rust (ts-rs)
 cargo check --manifest-path src-tauri/Cargo.toml
-bun run tauri build --bundles app  # local .app build
+bun run tauri build --bundles app      # local .app build (macOS)
+bun run tauri build --bundles appimage # local AppImage build (Linux)
 ```
 
 ### Project layout
 
 ```
 src/lib/modules/
-  audio/        cpal/SCK bridge, device enumeration, meter store
+  audio/        device enumeration, meter store
   flow/         xyflow node graph editor, sidebar, context menu
   pipeline/     pipeline state, snapshot history, ts-rs generated types
   form/         shared form primitives (combobox, slider)
   error/        global error modal (Rust panics + JS errors)
   updater/      auto-update modal + skip-version persistence
   app_info/     OS / app version cache
-src-tauri/src/
-  audio/        DSP engine, effects, encoders, pipeline DAG
-  commands.rs   Tauri command surface
-  lib.rs        app entry, plugin wiring, panic hook
+src-tauri/src/audio/
+  capture/      system + per-app capture (macos.rs SCK / linux.rs PipeWire)
+  device/       device enumeration (macos.rs CoreAudio / linux.rs PipeWire)
+  volume/       device volume (macos.rs / linux.rs)
+  virtual_device/  null-sink / driver management per OS
+  streams/      cpal stream builders (macOS)
+  playback.rs   PipeWire speaker output (Linux)
+  pipeline/     DSP engine, effects, encoders, pipeline DAG (input/, output/ per OS)
 src-tauri/native/virtual_driver/
-  SplitAudioDriver.cpp  AudioServerPlugin implementation (libASPL)
+  SplitAudioDriver.cpp  AudioServerPlugin implementation (libASPL, macOS)
   Info.plist            CFPlugin manifest
 ```