feat: add KWin/KDE Plasma screen capture via xdg-desktop-portal ScreenCast + PipeWire

Add a second capture backend for compositors without wlr-screencopy
(KWin, GNOME, etc.) using the xdg-desktop-portal ScreenCast interface
and PipeWire DMA-BUF streaming.

New files:
- src/backend_detect.rs: auto-detect wlr-screencopy vs portal backend
- src/cap_portal.rs: Portal session setup + PipeWire DMA-BUF thread
- src/state_portal.rs: StatePortal encoder pipeline (DMA-BUF → VAAPI)

Changes:
- Cargo.toml: add ashpd 0.13, tokio 1, pipewire 0.9, libspa 0.9,
  crossbeam-channel 0.5
- src/args.rs: add --backend CLI flag
- src/avhw.rs: extract create_encoder() from inline State code
- src/main.rs: route to portal or wlr-screencopy based on backend
- src/state.rs: fix params.destroy() on dup failure, cleanup
  in_flight_surface on copy fail, use create_encoder()
- tests/integration_test.rs: add --backend flag tests

.gitignore

@@ -16,4 +16,3 @@
 Thumbs.db
 
 # Sisyphus orchestration artifacts
-.sisyphus/

Cargo.toml

@@ -19,3 +19,8 @@ anyhow = "1"
 drm = "0.12"
 drm-fourcc = "2"
 libc = "0.2"
+ashpd = { version = "0.13", features = ["tokio", "screencast"] }
+tokio = { version = "1", features = ["rt"] }
+pipewire = "0.9"
+libspa = "0.9"
+crossbeam-channel = "0.5"

src/args.rs

@@ -39,6 +39,10 @@ pub struct Args {
     #[arg(short, long)]
     pub verbose: bool,
 
+    /// Capture backend to use: 'screencopy' (wlroots) or 'portal' (KWin/KDE). Auto-detected if omitted
+    #[arg(long)]
+    pub backend: Option<String>,
+
     /// Port for WebTransport server (Phase 2, unused in MVP)
     #[arg(long, default_value_t = 0)]
     pub port: u16,

src/avhw.rs

@@ -7,7 +7,7 @@ use ffmpeg_next as ff;
 use ffmpeg_next::ffi;
 use ffmpeg_next::packet::Mut as _;
 
-use crate::transform::Transform;
+use crate::transform::{transpose_if_transform_transposed, Transform};
 
 // ---------------------------------------------------------------------------
 // AvHwDevCtx
@@ -463,6 +463,46 @@ impl EncState {
     }
 }
 
+// ---------------------------------------------------------------------------
+// Shared encoder creation (used by both wlr-screencopy and portal paths)
+// ---------------------------------------------------------------------------
+
+/// Create a fully configured encoder with VAAPI hardware acceleration.
+///
+/// Convenience wrapper around [`EncState::new`] that computes default values
+/// for `bitrate` and `gop_size` when not provided, and handles encoder dimension
+/// transposition for rotated/transformed outputs.
+#[allow(clippy::too_many_arguments)]
+pub fn create_encoder(
+    drm_device: &Path,
+    output_path: &Path,
+    width: u32,
+    height: u32,
+    fps: u32,
+    transform: Transform,
+    bitrate: Option<u64>,
+    gop_size: Option<u32>,
+) -> Result<EncState> {
+    let (enc_w, enc_h) =
+        transpose_if_transform_transposed(transform, width as i32, height as i32);
+    let actual_bitrate = bitrate.unwrap_or_else(|| {
+        2 * (width as u64) * (height as u64) * (fps as u64) / 100
+    });
+    let actual_gop_size = gop_size.unwrap_or(fps);
+    EncState::new(
+        drm_device,
+        output_path,
+        width,
+        height,
+        enc_w as u32,
+        enc_h as u32,
+        actual_bitrate,
+        actual_gop_size,
+        fps,
+        transform,
+    )
+}
+
 // ---------------------------------------------------------------------------
 // Filter graph (inline)
 // ---------------------------------------------------------------------------
@@ -535,31 +575,30 @@ fn build_filter_graph(
     src_ctx.link(0, &mut scale_ctx, 0);
 
     match transform {
-        Transform::Normal90 | Transform::Normal270 => {
+        Transform::Normal => {
+            scale_ctx.link(0, &mut sink_ctx, 0);
+        }
+        other => {
             let transpose = ff::filter::find("transpose_vaapi")
                 .ok_or_else(|| anyhow::anyhow!("filter 'transpose_vaapi' not found"))?;
-            let dir_val = match transform {
+            let dir_val = match other {
                 Transform::Normal90 => "1",
+                Transform::Normal180 => "4",
                 Transform::Normal270 => "2",
-                _ => unreachable!(),
+                Transform::Flipped => "5",
+                Transform::Flipped90 => "3",
+                Transform::Flipped180 => "6",
+                Transform::Flipped270 => "0",
+                Transform::Normal => unreachable!(),
             };
-            let mut trans_ctx = graph.add(&transpose, "transpose", &format!("dir={dir_val}"))?;
-            // SAFETY: transpose_vaapi needs hw_device_ctx for VAAPI device access.
+            let mut trans_ctx =
+                graph.add(&transpose, "transpose", &format!("dir={dir_val}"))?;
             unsafe {
                 (*trans_ctx.as_mut_ptr()).hw_device_ctx = hw_dev.ref_clone();
             }
             scale_ctx.link(0, &mut trans_ctx, 0);
             trans_ctx.link(0, &mut sink_ctx, 0);
         }
-        Transform::Normal180 => {
-            tracing::warn!(
-                "Normal180 transform detected; rotation correction deferred to follow-up"
-            );
-            scale_ctx.link(0, &mut sink_ctx, 0);
-        }
-        _ => {
-            scale_ctx.link(0, &mut sink_ctx, 0);
-        }
     }
 
     graph

src/backend_detect.rs

@@ -0,0 +1,134 @@
+use anyhow::Result;
+use wayland_client::globals::registry_queue_init;
+use wayland_client::globals::GlobalListContents;
+use wayland_client::protocol::wl_registry::{Event, WlRegistry};
+use wayland_client::{Connection, Dispatch, QueueHandle};
+
+use crate::args::Args;
+
+/// Capture backend to use for screen capture.
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum CaptureBackend {
+    /// wlroots wlr-screencopy protocol (Sway, Hyprland, etc.)
+    WlrScreencopy,
+    /// xdg-desktop-portal with PipeWire (KWin/KDE, GNOME, etc.)
+    PortalPipeWire,
+}
+
+/// Minimal dispatch type for listing Wayland globals during backend detection.
+struct RegistryLs;
+
+impl Dispatch<WlRegistry, GlobalListContents> for RegistryLs {
+    fn event(
+        _state: &mut Self,
+        _registry: &WlRegistry,
+        _event: Event,
+        _data: &GlobalListContents,
+        _conn: &Connection,
+        _qhandle: &QueueHandle<Self>,
+    ) {
+    }
+}
+
+/// Detect which capture backend to use.
+///
+/// Priority:
+/// 1. Explicit `--backend` override from CLI args
+/// 2. Auto-detect by checking for `zwlr_screencopy_manager_v1` in Wayland globals
+///
+/// The detection Wayland connection is dropped before returning so the actual
+/// capture backend can create its own connection without holding two simultaneously.
+pub fn detect_backend(args: &Args) -> Result<CaptureBackend> {
+    // 1. Check explicit override
+    if let Some(ref backend) = args.backend {
+        return match backend.as_str() {
+            "portal" => {
+                tracing::info!("Backend override: Portal/PipeWire");
+                Ok(CaptureBackend::PortalPipeWire)
+            }
+            "screencopy" => {
+                tracing::info!("Backend override: wlr-screencopy");
+                Ok(CaptureBackend::WlrScreencopy)
+            }
+            other => {
+                anyhow::bail!(
+                    "Unknown backend '{}'. Use 'screencopy' or 'portal'.",
+                    other
+                );
+            }
+        };
+    }
+
+    // 2. Auto-detect: check if zwlr_screencopy_manager_v1 is available
+    tracing::info!("Auto-detecting capture backend...");
+    let conn = Connection::connect_to_env()?;
+    let (globals, _queue) = registry_queue_init::<RegistryLs>(&conn)?;
+
+    let has_screencopy = globals
+        .contents()
+        .clone_list()
+        .iter()
+        .any(|g| g.interface == "zwlr_screencopy_manager_v1");
+
+    // Drop the Wayland connection explicitly before returning.
+    // The screencopy path creates its own connection. Holding two connections
+    // simultaneously is wasteful and may cause issues on some compositors.
+    drop(conn);
+
+    if has_screencopy {
+        tracing::info!("Detected wlr-screencopy support → using WlrScreencopy backend");
+        Ok(CaptureBackend::WlrScreencopy)
+    } else {
+        tracing::info!("No wlr-screencopy support → using Portal/PipeWire backend");
+        Ok(CaptureBackend::PortalPipeWire)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn make_args(backend: Option<&str>) -> Args {
+        Args {
+            output: "test.mp4".to_string(),
+            output_name: None,
+            fps: 30,
+            codec: "h264".to_string(),
+            hw_accel: "vaapi".to_string(),
+            drm_device: None,
+            bitrate: None,
+            gop_size: None,
+            verbose: false,
+            backend: backend.map(String::from),
+            port: 0,
+        }
+    }
+
+    #[test]
+    fn explicit_portal_backend() {
+        let args = make_args(Some("portal"));
+        let result = detect_backend(&args);
+        assert!(result.is_ok());
+        assert_eq!(result.unwrap(), CaptureBackend::PortalPipeWire);
+    }
+
+    #[test]
+    fn explicit_screencopy_backend() {
+        let args = make_args(Some("screencopy"));
+        let result = detect_backend(&args);
+        assert!(result.is_ok());
+        assert_eq!(result.unwrap(), CaptureBackend::WlrScreencopy);
+    }
+
+    #[test]
+    fn invalid_backend_name_returns_error() {
+        let args = make_args(Some("magic"));
+        let result = detect_backend(&args);
+        assert!(result.is_err());
+        let err = result.unwrap_err().to_string();
+        assert!(
+            err.contains("Unknown backend 'magic'"),
+            "Expected error about unknown backend, got: {err}"
+        );
+    }
+}

src/cap_portal.rs

@@ -0,0 +1,411 @@
+use std::os::fd::{FromRawFd, OwnedFd};
+use std::thread::{self, JoinHandle};
+
+use anyhow::Result;
+use crossbeam_channel::{Receiver, Sender, bounded};
+use tokio::runtime::Runtime;
+
+use crate::args::Args;
+
+pub struct PwDmaBufFrame {
+    pub fd: OwnedFd,
+    pub offset: u64,
+    pub stride: u32,
+    pub modifier: u64,
+    pub width: u32,
+    pub height: u32,
+    pub format: u32,
+    pub pts: i64,
+}
+
+pub enum PwEvent {
+    Frame(PwDmaBufFrame),
+    StreamEnded,
+    Error(String),
+}
+
+pub enum PwCmd {
+    Shutdown,
+}
+
+pub struct CapPortal {
+    cmd_tx: Sender<PwCmd>,
+    frame_rx: Receiver<PwEvent>,
+    pw_thread: Option<JoinHandle<()>>,
+    rt: Runtime,
+}
+
+struct PwThreadCtx {
+    frame_tx: Sender<PwEvent>,
+    cmd_rx: Receiver<PwCmd>,
+    pw_fd: OwnedFd,
+    node_id: u32,
+    fps: u32,
+}
+
+impl CapPortal {
+    pub fn new(args: &Args) -> Result<Self> {
+        let rt = Runtime::new()?;
+
+        let (pw_fd, node_id) = rt.block_on(async {
+            Self::setup_portal().await
+        })?;
+
+        let (frame_tx, frame_rx) = bounded(3);
+        let (cmd_tx, cmd_rx) = bounded(1);
+
+        let ctx = PwThreadCtx {
+            frame_tx,
+            cmd_rx,
+            pw_fd,
+            node_id,
+            fps: args.fps,
+        };
+
+        let pw_thread = thread::Builder::new()
+            .name("pipewire-capture".into())
+            .spawn(move || {
+                pipewire_thread(ctx);
+            })?;
+
+        Ok(Self {
+            cmd_tx,
+            frame_rx,
+            pw_thread: Some(pw_thread),
+            rt,
+        })
+    }
+
+    pub fn frame_receiver(&self) -> &Receiver<PwEvent> {
+        &self.frame_rx
+    }
+
+    async fn setup_portal() -> Result<(OwnedFd, u32)> {
+        use ashpd::desktop::screencast::{
+            CursorMode, Screencast, SelectSourcesOptions, SourceType,
+        };
+        use ashpd::desktop::PersistMode;
+
+        let proxy = Screencast::new().await.map_err(|e| {
+            anyhow::anyhow!("Failed to create Screencast proxy: {e}")
+        })?;
+
+        let session = proxy
+            .create_session(Default::default())
+            .await
+            .map_err(|e| anyhow::anyhow!("Failed to create ScreenCast session: {e}"))?;
+
+        proxy
+            .select_sources(
+                &session,
+                SelectSourcesOptions::default()
+                    .set_cursor_mode(CursorMode::Embedded)
+                    .set_sources(ashpd::enumflags2::BitFlags::from(SourceType::Monitor))
+                    .set_multiple(false)
+                    .set_persist_mode(PersistMode::DoNot),
+            )
+            .await
+            .map_err(|e| {
+                anyhow::anyhow!("屏幕共享权限被拒绝 / Screen sharing permission denied: {e}")
+            })?;
+
+        let response = proxy
+            .start(&session, None, Default::default())
+            .await
+            .map_err(|e| anyhow::anyhow!("ScreenCast start failed: {e}"))?
+            .response()
+            .map_err(|e| anyhow::anyhow!("ScreenCast response error: {e}"))?;
+
+        let stream = response
+            .streams()
+            .first()
+            .ok_or_else(|| anyhow::anyhow!("No streams returned from ScreenCast"))?;
+
+        let node_id = stream.pipe_wire_node_id();
+
+        let fd = proxy
+            .open_pipe_wire_remote(&session, Default::default())
+            .await
+            .map_err(|e| anyhow::anyhow!("Failed to open PipeWire remote: {e}"))?;
+
+        tracing::info!("Portal session established: node_id={node_id}");
+
+        Ok((fd, node_id))
+    }
+}
+
+impl Drop for CapPortal {
+    fn drop(&mut self) {
+        let _ = self.cmd_tx.send(PwCmd::Shutdown);
+
+        if let Some(handle) = self.pw_thread.take() {
+            let _ = handle.join();
+        }
+    }
+}
+
+fn pipewire_thread(ctx: PwThreadCtx) {
+    use pipewire as pw;
+    use pw::properties::properties;
+    use pw::stream::{StreamBox, StreamFlags};
+    use std::cell::Cell;
+    use std::rc::Rc;
+    use pw::spa::param::video::VideoInfoRaw;
+
+    pw::init();
+
+    let PwThreadCtx {
+        frame_tx,
+        cmd_rx,
+        pw_fd,
+        node_id,
+        fps: _fps,
+    } = ctx;
+
+    let mainloop = match pw::main_loop::MainLoopBox::new(None) {
+        Ok(ml) => ml,
+        Err(e) => {
+            let _ = frame_tx.send(PwEvent::Error(format!("MainLoop::new failed: {e}")));
+            return;
+        }
+    };
+
+    let context = match pw::context::ContextBox::new(mainloop.loop_(), None) {
+        Ok(c) => c,
+        Err(e) => {
+            let _ = frame_tx.send(PwEvent::Error(format!("Context::new failed: {e}")));
+            return;
+        }
+    };
+
+    let core = match context.connect_fd(pw_fd, None) {
+        Ok(c) => c,
+        Err(e) => {
+            let _ = frame_tx.send(PwEvent::Error(format!("connect_fd failed: {e}")));
+            return;
+        }
+    };
+
+    let stream = match StreamBox::new(
+        &core,
+        "wl-webrtc",
+        properties! {
+            *pw::keys::MEDIA_TYPE => "Video",
+            *pw::keys::MEDIA_CATEGORY => "Capture",
+            *pw::keys::MEDIA_ROLE => "Screen",
+        },
+    ) {
+        Ok(s) => s,
+        Err(e) => {
+            let _ = frame_tx.send(PwEvent::Error(format!("Stream::new failed: {e}")));
+            return;
+        }
+    };
+
+    // Shared format state: (width, height, drm_fourcc, modifier)
+    let format_info: Rc<Cell<Option<(u32, u32, u32, u64)>>> =
+        Rc::new(Cell::new(None));
+
+    let frame_tx_clone = frame_tx.clone();
+    let _listener = stream
+        .add_local_listener::<()>()
+        .state_changed(move |_, _, old, new| {
+            tracing::debug!("PipeWire stream state: {old:?} -> {new:?}");
+            match new {
+                pw::stream::StreamState::Error(_)
+                | pw::stream::StreamState::Unconnected => {
+                    let _ = frame_tx_clone.send(PwEvent::StreamEnded);
+                }
+                _ => {}
+            }
+        })
+        .param_changed({
+            let format_info = format_info.clone();
+            move |_, _, id, param| {
+                let Some(param) = param else { return };
+                if id != pw::spa::param::ParamType::Format.as_raw() {
+                    return;
+                }
+                let mut info = VideoInfoRaw::new();
+                if let Err(e) = info.parse(param) {
+                    tracing::warn!("Failed to parse video format: {e}");
+                    return;
+                }
+                let width = info.size().width;
+                let height = info.size().height;
+                let drm_format = spa_to_drm_fourcc(info.format());
+                let modifier = info.modifier();
+                format_info.set(Some((width, height, drm_format, modifier)));
+                tracing::info!(
+                    "PipeWire format negotiated: {width}x{height}, \
+                     drm_format={drm_format:#010x}, modifier={modifier:#x}"
+                );
+            }
+        })
+        .process({
+            let format_info = format_info.clone();
+            let frame_tx = frame_tx.clone();
+            move |stream, _| {
+                let raw_buf = unsafe { stream.dequeue_raw_buffer() };
+                if raw_buf.is_null() {
+                    return;
+                }
+
+                let spa_buf = unsafe { (*raw_buf).buffer };
+                if spa_buf.is_null() {
+                    unsafe { stream.queue_raw_buffer(raw_buf) };
+                    return;
+                }
+
+                let n_datas = unsafe { (*spa_buf).n_datas };
+                let datas_ptr = unsafe { (*spa_buf).datas };
+                if n_datas == 0 || datas_ptr.is_null() {
+                    unsafe { stream.queue_raw_buffer(raw_buf) };
+                    return;
+                }
+
+                // Access first data item through libspa Data wrapper
+                let data_ref: &pw::spa::buffer::Data = unsafe { &*(datas_ptr as *const pw::spa::buffer::Data) };
+                let fd = data_ref.fd();
+                if fd < 0 {
+                    unsafe { stream.queue_raw_buffer(raw_buf) };
+                    return;
+                }
+
+                let chunk = data_ref.chunk();
+                let offset = chunk.offset() as u64;
+                let stride = chunk.stride() as u32;
+
+                // Get PTS from SPA_META_Header metadata
+                let pts: i64 = unsafe {
+                    let mut pts_val: i64 = 0;
+                    let n_metas = (*spa_buf).n_metas;
+                    let metas = (*spa_buf).metas;
+                    if !metas.is_null() {
+                        for i in 0..n_metas {
+                            let meta = &*metas.add(i as usize);
+                            if meta.type_ == libspa::sys::SPA_META_Header
+                                && meta.size as usize >= std::mem::size_of::<libspa::sys::spa_meta_header>()
+                                && !meta.data.is_null()
+                            {
+                                let header = &*(meta.data as *const libspa::sys::spa_meta_header);
+                                pts_val = header.pts;
+                                break;
+                            }
+                        }
+                    }
+                    pts_val
+                };
+
+                let dup_fd = unsafe { libc::dup(fd) };
+                if dup_fd < 0 {
+                    unsafe { stream.queue_raw_buffer(raw_buf) };
+                    return;
+                }
+
+                let (width, height, format, modifier) =
+                    format_info.get().unwrap_or((0, 0, 0, 0));
+
+                let frame = PwDmaBufFrame {
+                    fd: unsafe { OwnedFd::from_raw_fd(dup_fd) },
+                    offset,
+                    stride,
+                    modifier,
+                    width,
+                    height,
+                    format,
+                    pts,
+                };
+
+                let _ = frame_tx.send(PwEvent::Frame(frame));
+                unsafe { stream.queue_raw_buffer(raw_buf) };
+            }
+        })
+        .register();
+
+    let mut params: [&pw::spa::pod::Pod; 0] = [];
+
+    if let Err(e) = stream.connect(
+        pw::spa::utils::Direction::Input,
+        Some(node_id),
+        StreamFlags::AUTOCONNECT | StreamFlags::MAP_BUFFERS,
+        &mut params,
+    ) {
+        let _ = frame_tx.send(PwEvent::Error(format!("stream.connect failed: {e}")));
+        return;
+    }
+
+    let loop_ = mainloop.loop_();
+    loop_.add_signal_local(
+        pw::loop_::Signal::SIGINT,
+        Box::new(|| {}),
+    );
+    loop_.add_signal_local(
+        pw::loop_::Signal::SIGTERM,
+        Box::new(|| {}),
+    );
+
+    // Store raw pointer as usize so it is Send-safe across threads.
+    // PipeWire's pw_main_loop_quit is thread-safe by design.
+    let mainloop_ptr = mainloop.as_raw_ptr() as usize;
+    let cmd_rx_moved = cmd_rx;
+    std::thread::spawn(move || {
+        let _ = cmd_rx_moved.recv();
+        // SAFETY: mainloop is still alive on the pipewire thread while we wait
+        // for cmd_rx, and quit() is thread-safe in PipeWire C API.
+        unsafe { pipewire::sys::pw_main_loop_quit(mainloop_ptr as *mut _) };
+    });
+
+    mainloop.run();
+
+    // SAFETY: pipewire has been initialized with pw::init() above and all
+    // PipeWire resources (mainloop, stream) have been dropped.
+    unsafe { pw::deinit() };
+}
+
+const fn fourcc(a: u8, b: u8, c: u8, d: u8) -> u32 {
+    (a as u32) | ((b as u32) << 8) | ((c as u32) << 16) | ((d as u32) << 24)
+}
+
+fn spa_to_drm_fourcc(format: libspa::param::video::VideoFormat) -> u32 {
+    use libspa::param::video::VideoFormat;
+    match format {
+        VideoFormat::BGRA => fourcc(b'B', b'G', b'R', b'A'),
+        VideoFormat::BGRx => fourcc(b'B', b'G', b'R', b'X'),
+        VideoFormat::RGBA => fourcc(b'R', b'G', b'B', b'A'),
+        VideoFormat::RGBx => fourcc(b'R', b'G', b'B', b'X'),
+        VideoFormat::ARGB => fourcc(b'A', b'R', b'2', b'4'),
+        VideoFormat::xRGB => fourcc(b'X', b'R', b'2', b'4'),
+        VideoFormat::ABGR => fourcc(b'A', b'B', b'2', b'4'),
+        VideoFormat::xBGR => fourcc(b'X', b'B', b'2', b'4'),
+        _ => 0,
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn spa_to_drm_fourcc_bgra() {
+        use libspa::param::video::VideoFormat;
+        assert_eq!(spa_to_drm_fourcc(VideoFormat::BGRA), fourcc(b'B', b'G', b'R', b'A'));
+    }
+
+    #[test]
+    fn spa_to_drm_fourcc_rgba() {
+        use libspa::param::video::VideoFormat;
+        assert_eq!(spa_to_drm_fourcc(VideoFormat::RGBA), fourcc(b'R', b'G', b'B', b'A'));
+    }
+
+    #[test]
+    fn spa_to_drm_fourcc_unknown_returns_zero() {
+        use libspa::param::video::VideoFormat;
+        assert_eq!(spa_to_drm_fourcc(VideoFormat::Unknown), 0);
+    }
+
+    #[test]
+    fn fourcc_encoding() {
+        assert_eq!(fourcc(b'B', b'G', b'R', b'A'), 0x41524742);
+    }
+}

src/main.rs

@@ -9,9 +9,12 @@ use wayland_client::Connection;
 
 mod args;
 mod avhw;
+mod backend_detect;
+mod cap_portal;
 mod cap_wlr_screencopy;
 mod fps_limit;
 mod state;
+mod state_portal;
 mod transform;
 
 use crate::args::Args;
@@ -40,6 +43,19 @@ fn main() -> Result<()> {
         anyhow::bail!("HEVC not supported in MVP. Use --codec h264");
     }
 
+    let backend = crate::backend_detect::detect_backend(&args)?;
+
+    match backend {
+        crate::backend_detect::CaptureBackend::WlrScreencopy => {
+            run_wlr_screencopy(args)
+        }
+        crate::backend_detect::CaptureBackend::PortalPipeWire => {
+            run_portal_pipewire(args)
+        }
+    }
+}
+
+fn run_wlr_screencopy(args: Args) -> Result<()> {
     // Connect to Wayland compositor
     let conn = Connection::connect_to_env()?;
     let (gm, mut queue) = registry_queue_init::<State<CapWlrScreencopy>>(&conn)?;
@@ -158,3 +174,58 @@ fn main() -> Result<()> {
     tracing::info!("Done");
     Ok(())
 }
+
+fn run_portal_pipewire(args: Args) -> Result<()> {
+    use crate::state_portal::StatePortal;
+
+    tracing::info!("Using Portal/PipeWire backend (KWin/KDE/GNOME)");
+
+    let mut state = StatePortal::new(args)?;
+
+    // Set up signal handling only (no Wayland fd needed)
+    let mut signals = signal_hook_mio::v1_0::Signals::new(&[
+        signal_hook::consts::SIGINT,
+        signal_hook::consts::SIGTERM,
+    ])?;
+
+    let mut poll = mio::Poll::new()?;
+    let mut events = mio::Events::with_capacity(8);
+
+    poll.registry().register(
+        &mut signals,
+        mio::Token(1),
+        mio::Interest::READABLE,
+    )?;
+
+    let mut running = true;
+    while running {
+        poll.poll(&mut events, Some(std::time::Duration::from_millis(10)))
+            .unwrap_or_else(|e| {
+                if e.kind() == std::io::ErrorKind::Interrupted {
+                    return;
+                }
+                tracing::error!("poll failed: {e}");
+                running = false;
+            });
+
+        for event in &events {
+            if event.token() == mio::Token(1) {
+                tracing::info!("Received quit signal");
+                running = false;
+            }
+        }
+
+        // Process all available PipeWire frames
+        while state.poll_and_encode()? {}
+
+        if state.is_errored() {
+            tracing::error!("Fatal error in portal state machine, exiting");
+            running = false;
+        }
+    }
+
+    tracing::info!("Shutting down...");
+    state.shutdown();
+    tracing::info!("Done");
+    Ok(())
+}

src/state.rs

@@ -465,6 +465,8 @@ impl<S: CaptureSource> State<S> {
                 let fd_dup = unsafe { libc::dup(obj.fd) };
                 if fd_dup < 0 {
                     tracing::error!("failed to dup dma-buf fd");
+                    // wayland-client does not auto-destroy params on Drop.
+                    params.destroy();
                     self.errored = true;
                     return;
                 }
@@ -553,8 +555,27 @@ impl<S: CaptureSource> State<S> {
         }
     }
 
-    pub fn on_copy_fail(&mut self) {
+    pub fn on_copy_fail(&mut self)
+    where
+        S::Frame: Default,
+    {
         tracing::error!("compositor copy failed");
+        let taken = mem::replace(&mut self.in_flight_surface, InFlightSurface::None);
+        match taken {
+            InFlightSurface::CopyQueued {
+                buffer,
+                frame,
+                ..
+            } => {
+                drop(buffer);
+                if let EncConstructionStage::Streaming { cap, .. } = &mut self.stage {
+                    cap.on_done_with_frame(frame);
+                }
+            }
+            other => {
+                self.in_flight_surface = other;
+            }
+        }
         self.errored = true;
     }
 
@@ -576,25 +597,19 @@ impl<S: CaptureSource> State<S> {
         };
         let (output_info, output, cap, screencopy_manager, dmabuf) = stage_data;
         let drm_path = self.resolve_drm_path();
-        let bitrate = self.args.bitrate.unwrap_or_else(|| {
-            let fps = self.args.fps as u64;
-            2 * (width as u64) * (height as u64) * fps / 100
-        });
-        let gop_size = self.args.gop_size.unwrap_or(self.args.fps);
         let fps = self.args.fps;
-        let (enc_w, enc_h) =
-            transpose_if_transform_transposed(output_info.transform, width as i32, height as i32);
-        let enc = match EncState::new(
+        let bitrate = self.args.bitrate.unwrap_or_else(|| {
+            2 * (width as u64) * (height as u64) * (fps as u64) / 100
+        });
+        let enc = match crate::avhw::create_encoder(
             &drm_path,
             Path::new(&self.args.output),
             width,
             height,
-            enc_w as u32,
-            enc_h as u32,
-            bitrate,
-            gop_size,
             fps,
             output_info.transform,
+            self.args.bitrate,
+            self.args.gop_size,
         ) {
             Ok(enc) => enc,
             Err(e) => {
@@ -1175,21 +1190,24 @@ impl<S: CaptureSource> Dispatch<ZwpLinuxBufferParamsV1, ()> for State<S> {
             }
             BufferParamsEvent::Failed => {
                 tracing::error!("DMA-BUF buffer creation failed");
-                state.errored = true;
-                match mem::replace(&mut state.in_flight_surface, InFlightSurface::None) {
+                let taken = mem::replace(&mut state.in_flight_surface, InFlightSurface::None);
+                match taken {
                     InFlightSurface::CopyQueued {
-                        surface: _,
-                        drm_map: _,
-                        frame: _,
                         buffer,
+                        frame,
+                        ..
                     } => {
                         drop(buffer);
+                        if let EncConstructionStage::Streaming { cap, .. } = &mut state.stage {
+                            cap.on_done_with_frame(frame);
+                        }
                     }
                     other => {
                         state.in_flight_surface = other;
                     }
                 }
                 proxy.destroy();
+                state.errored = true;
             }
             _ => {}
         }

src/state_portal.rs

@@ -0,0 +1,306 @@
+use std::mem;
+use std::path::PathBuf;
+
+use anyhow::{bail, Result};
+use ffmpeg_next as ff;
+use ffmpeg_next::ffi;
+
+use crate::args::Args;
+use crate::avhw::{self, EncState};
+use crate::cap_portal::{CapPortal, PwDmaBufFrame, PwEvent};
+use crate::fps_limit::FpsLimit;
+use crate::transform::Transform;
+
+enum PortalStage {
+    WaitingForFormat,
+    Streaming,
+}
+
+pub struct StatePortal {
+    stage: PortalStage,
+    enc: Option<EncState>,
+    fps_limit: FpsLimit<()>,
+    cap: CapPortal,
+    args: Args,
+    errored: bool,
+    first_frame: bool,
+    drm_device: PathBuf,
+}
+
+impl StatePortal {
+    pub fn new(args: Args) -> Result<Self> {
+        let drm_device = resolve_drm_device(&args)?;
+        tracing::info!("Using DRM device: {}", drm_device.display());
+
+        let cap = CapPortal::new(&args)?;
+
+        Ok(Self {
+            stage: PortalStage::WaitingForFormat,
+            enc: None,
+            fps_limit: FpsLimit::new(args.fps),
+            cap,
+            args,
+            errored: false,
+            first_frame: true,
+            drm_device,
+        })
+    }
+
+    pub fn poll_and_encode(&mut self) -> Result<bool> {
+        let event = match self.cap.frame_receiver().try_recv() {
+            Ok(event) => event,
+            Err(_) => return Ok(false),
+        };
+
+        match event {
+            PwEvent::Frame(frame) => {
+                match self.stage {
+                    PortalStage::WaitingForFormat => {
+                        tracing::info!(
+                            "First DMA-BUF frame: {}x{} format=0x{:08X} stride={} modifier=0x{:X}",
+                            frame.width,
+                            frame.height,
+                            frame.format,
+                            frame.stride,
+                            frame.modifier
+                        );
+
+                        let enc = avhw::create_encoder(
+                            &self.drm_device,
+                            self.args.output.as_ref(),
+                            frame.width,
+                            frame.height,
+                            self.args.fps,
+                            Transform::Normal,
+                            self.args.bitrate,
+                            self.args.gop_size,
+                        )?;
+
+                        self.enc = Some(enc);
+                        self.stage = PortalStage::Streaming;
+                        drop(frame);
+                    }
+                    PortalStage::Streaming => {
+                        self.handle_pw_frame(frame)?;
+                    }
+                }
+            }
+            PwEvent::StreamEnded => {
+                tracing::warn!("PipeWire stream ended");
+                self.errored = true;
+            }
+            PwEvent::Error(e) => {
+                tracing::error!("PipeWire error: {e}");
+                self.errored = true;
+            }
+        }
+
+        Ok(true)
+    }
+
+    fn handle_pw_frame(&mut self, frame: PwDmaBufFrame) -> Result<()> {
+        // 1. FPS limiting (first frame bypasses)
+        if self.first_frame {
+            self.first_frame = false;
+        } else {
+            let now = std::time::Instant::now();
+            if self.fps_limit.on_new_frame((), now).is_none() {
+                return Ok(());
+            }
+        }
+
+        // 2. Build DRM descriptor for DMA-BUF import
+        let desc = build_drm_descriptor(&frame);
+        let desc_box = Box::new(desc);
+
+        // 3. Allocate raw DRM_PRIME source frame using Video wrapper
+        let mut raw_frame = ff::frame::Video::empty();
+        unsafe {
+            let raw_ptr = raw_frame.as_mut_ptr();
+            (*raw_ptr).data[0] = Box::into_raw(desc_box) as *mut u8;
+            (*raw_ptr).format = ffi::AVPixelFormat::AV_PIX_FMT_DRM_PRIME as i32;
+            (*raw_ptr).width = frame.width as i32;
+            (*raw_ptr).height = frame.height as i32;
+        }
+
+        // 4. Get encoder reference
+        let enc = match self.enc.as_mut() {
+            Some(e) => e,
+            None => {
+                // Recover the Box to prevent memory leak of the descriptor
+                unsafe {
+                    let desc_ptr = (*raw_frame.as_ptr()).data[0] as *mut ffi::AVDRMFrameDescriptor;
+                    if !desc_ptr.is_null() {
+                        let _ = Box::from_raw(desc_ptr);
+                    }
+                }
+                bail!("encoder not initialized");
+            }
+        };
+
+        // 5. Allocate VAAPI hardware target frame
+        let mut hw_frame = ff::frame::Video::empty();
+        let ret = unsafe {
+            ffi::av_hwframe_get_buffer(enc.frames_rgb().as_ptr(), hw_frame.as_mut_ptr(), 0)
+        };
+        if ret < 0 {
+            // Recover the Box to prevent memory leak of the descriptor
+            unsafe {
+                let desc_ptr = (*raw_frame.as_ptr()).data[0] as *mut ffi::AVDRMFrameDescriptor;
+                if !desc_ptr.is_null() {
+                    let _ = Box::from_raw(desc_ptr);
+                }
+            }
+            bail!("av_hwframe_get_buffer failed: error {ret}");
+        }
+
+        // 6. Import DMA-BUF into VAAPI via transfer_data
+        let ret = unsafe {
+            ffi::av_hwframe_transfer_data(hw_frame.as_mut_ptr(), raw_frame.as_ptr(), 0)
+        };
+        if ret < 0 {
+            unsafe {
+                let desc_ptr = (*raw_frame.as_ptr()).data[0] as *mut ffi::AVDRMFrameDescriptor;
+                if !desc_ptr.is_null() {
+                    let _ = Box::from_raw(desc_ptr);
+                }
+            }
+            if ret == -(ffi::EINVAL as i32) {
+                bail!(
+                    "VAAPI does not support DMA-BUF modifier 0x{:X}",
+                    frame.modifier
+                );
+            }
+            bail!("av_hwframe_transfer_data failed: error {ret}");
+        }
+
+        // 7. Set PTS
+        unsafe {
+            (*hw_frame.as_mut_ptr()).pts = frame.pts;
+        }
+
+        // 8. Encode
+        enc.encode_frame(&hw_frame)?;
+
+        // 9. Clean up: recover the Boxed descriptor from raw_frame to prevent leak.
+        //    Video::drop calls av_frame_free which does NOT free data[0].
+        unsafe {
+            let desc_ptr = (*raw_frame.as_ptr()).data[0] as *mut ffi::AVDRMFrameDescriptor;
+            if !desc_ptr.is_null() {
+                let _ = Box::from_raw(desc_ptr);
+            }
+        }
+        // raw_frame and hw_frame drop here via Video::drop → av_frame_free
+
+        Ok(())
+    }
+
+    pub fn flush(&mut self) -> Result<()> {
+        if let Some(enc) = &mut self.enc {
+            enc.flush()?;
+        }
+        Ok(())
+    }
+
+    pub fn shutdown(&mut self) {
+        if let Err(e) = self.flush() {
+            tracing::error!("Flush error during shutdown: {e}");
+        }
+        tracing::info!("StatePortal shutdown complete");
+    }
+
+    pub fn is_errored(&self) -> bool {
+        self.errored
+    }
+}
+
+fn build_drm_descriptor(frame: &PwDmaBufFrame) -> ffi::AVDRMFrameDescriptor {
+    let mut desc: ffi::AVDRMFrameDescriptor = unsafe { mem::zeroed() };
+
+    desc.nb_objects = 1;
+    desc.objects[0].fd = frame.fd.as_raw_fd();
+    desc.objects[0].size = 0;
+    desc.objects[0].format_modifier = frame.modifier;
+
+    desc.nb_layers = 1;
+    desc.layers[0].format = frame.format;
+    desc.layers[0].nb_planes = 1;
+    desc.layers[0].planes[0].object_index = 0;
+    desc.layers[0].planes[0].offset = frame.offset as isize;
+    desc.layers[0].planes[0].pitch = frame.stride as isize;
+
+    desc
+}
+
+use std::os::fd::AsRawFd;
+
+fn resolve_drm_device(args: &Args) -> Result<PathBuf> {
+    if let Some(ref drm) = args.drm_device {
+        return Ok(PathBuf::from(drm));
+    }
+
+    for render in &["/dev/dri/renderD128", "/dev/dri/renderD129"] {
+        let path = PathBuf::from(render);
+        if path.exists() {
+            return Ok(path);
+        }
+    }
+
+    bail!("No DRM render device found. Specify --drm-device.")
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use std::os::fd::{FromRawFd, OwnedFd};
+
+    fn make_test_frame() -> PwDmaBufFrame {
+        // Create a dummy fd from stderr (always valid fd 2)
+        let fd = unsafe { OwnedFd::from_raw_fd(libc::dup(2)) };
+        PwDmaBufFrame {
+            fd,
+            offset: 0,
+            stride: 1920 * 4,
+            modifier: 0, // DRM_FORMAT_MOD_LINEAR
+            width: 1920,
+            height: 1080,
+            format: 0x34325258, // XR24 little-endian
+            pts: 12345,
+        }
+    }
+
+    #[test]
+    fn build_drm_descriptor_single_plane() {
+        let frame = make_test_frame();
+        let desc = build_drm_descriptor(&frame);
+
+        assert_eq!(desc.nb_objects, 1);
+        assert_eq!(desc.objects[0].format_modifier, 0);
+        assert_eq!(desc.nb_layers, 1);
+        assert_eq!(desc.layers[0].format, 0x34325258);
+        assert_eq!(desc.layers[0].nb_planes, 1);
+        assert_eq!(desc.layers[0].planes[0].object_index, 0);
+        assert_eq!(desc.layers[0].planes[0].offset, 0);
+        assert_eq!(desc.layers[0].planes[0].pitch, 1920 * 4);
+    }
+
+    #[test]
+    fn resolve_drm_device_explicit() {
+        let args = Args {
+            output: "test.mp4".to_string(),
+            output_name: None,
+            fps: 30,
+            codec: "h264".to_string(),
+            hw_accel: "vaapi".to_string(),
+            drm_device: Some("/dev/dri/renderD128".to_string()),
+            bitrate: None,
+            gop_size: None,
+            verbose: false,
+            backend: None,
+            port: 0,
+        };
+        let result = resolve_drm_device(&args);
+        assert!(result.is_ok());
+        assert_eq!(result.unwrap(), std::path::PathBuf::from("/dev/dri/renderD128"));
+    }
+}

src/transform.rs

@@ -56,12 +56,7 @@ pub fn transform_basis(transform: Transform) -> (i32, i32, i32, i32) {
 /// new_x = a * x + b * y + offset_x
 /// new_y = c * x + d * y + offset_y
 /// ```
-pub fn screen_to_frame(
-    transform: Transform,
-    rect: Rect,
-    frame_w: i32,
-    frame_h: i32,
-) -> Rect {
+pub fn screen_to_frame(transform: Transform, rect: Rect, frame_w: i32, frame_h: i32) -> Rect {
     let (a, b, c, d) = transform_basis(transform);
 
     // Compute the offset so that the transformed origin maps correctly.
@@ -90,9 +85,10 @@ pub fn screen_to_frame(
 /// and `(w, h)` unchanged otherwise.
 pub fn transpose_if_transform_transposed(transform: Transform, w: i32, h: i32) -> (i32, i32) {
     match transform {
-        Transform::Normal90 | Transform::Normal270 | Transform::Flipped90 | Transform::Flipped270 => {
-            (h, w)
-        }
+        Transform::Normal90
+        | Transform::Normal270
+        | Transform::Flipped90
+        | Transform::Flipped270 => (h, w),
         _ => (w, h),
     }
 }
@@ -161,15 +157,33 @@ mod tests {
 
     #[test]
     fn screen_to_frame_identity_unchanged() {
-        let rect = Rect { x: 10, y: 20, w: 100, h: 50 };
+        let rect = Rect {
+            x: 10,
+            y: 20,
+            w: 100,
+            h: 50,
+        };
         let result = screen_to_frame(Transform::Normal, rect, 1920, 1080);
-        assert_eq!(result, Rect { x: 10, y: 20, w: 100, h: 50 });
+        assert_eq!(
+            result,
+            Rect {
+                x: 10,
+                y: 20,
+                w: 100,
+                h: 50
+            }
+        );
     }
 
     #[test]
     fn screen_to_frame_90_rotates_origin() {
         // 90° CW: top-left (0,0) in screen should map to bottom-left in frame
-        let rect = Rect { x: 0, y: 0, w: 100, h: 50 };
+        let rect = Rect {
+            x: 0,
+            y: 0,
+            w: 100,
+            h: 50,
+        };
         let result = screen_to_frame(Transform::Normal90, rect, 1080, 1920);
         // a=0,b=1,c=-1,d=0 => offset_x=0, offset_y=1920 (c+d=-1<0)
         // new_x = 0*0 + 1*0 + 0 = 0
@@ -183,7 +197,12 @@ mod tests {
 
     #[test]
     fn screen_to_frame_180_rotates() {
-        let rect = Rect { x: 100, y: 200, w: 300, h: 400 };
+        let rect = Rect {
+            x: 100,
+            y: 200,
+            w: 300,
+            h: 400,
+        };
         let result = screen_to_frame(Transform::Normal180, rect, 1920, 1080);
         // a=-1,b=0,c=0,d=-1, offset_x=1920, offset_y=1080
         assert_eq!(result.x, -100 + 1920);
@@ -194,7 +213,12 @@ mod tests {
 
     #[test]
     fn screen_to_frame_flipped_horizontal() {
-        let rect = Rect { x: 50, y: 30, w: 200, h: 100 };
+        let rect = Rect {
+            x: 50,
+            y: 30,
+            w: 200,
+            h: 100,
+        };
         let result = screen_to_frame(Transform::Flipped, rect, 1920, 1080);
         // a=-1,b=0,c=0,d=1, offset_x=1920, offset_y=0
         assert_eq!(result.x, -50 + 1920);
@@ -207,85 +231,179 @@ mod tests {
 
     #[test]
     fn transpose_normal_no_swap() {
-        assert_eq!(transpose_if_transform_transposed(Transform::Normal, 1920, 1080), (1920, 1080));
+        assert_eq!(
+            transpose_if_transform_transposed(Transform::Normal, 1920, 1080),
+            (1920, 1080)
+        );
     }
 
     #[test]
     fn transpose_90_swaps() {
-        assert_eq!(transpose_if_transform_transposed(Transform::Normal90, 1920, 1080), (1080, 1920));
+        assert_eq!(
+            transpose_if_transform_transposed(Transform::Normal90, 1920, 1080),
+            (1080, 1920)
+        );
     }
 
     #[test]
     fn transpose_180_no_swap() {
-        assert_eq!(transpose_if_transform_transposed(Transform::Normal180, 1920, 1080), (1920, 1080));
+        assert_eq!(
+            transpose_if_transform_transposed(Transform::Normal180, 1920, 1080),
+            (1920, 1080)
+        );
     }
 
     #[test]
     fn transpose_270_swaps() {
-        assert_eq!(transpose_if_transform_transposed(Transform::Normal270, 1920, 1080), (1080, 1920));
+        assert_eq!(
+            transpose_if_transform_transposed(Transform::Normal270, 1920, 1080),
+            (1080, 1920)
+        );
     }
 
     #[test]
     fn transpose_flipped_no_swap() {
-        assert_eq!(transpose_if_transform_transposed(Transform::Flipped, 1920, 1080), (1920, 1080));
+        assert_eq!(
+            transpose_if_transform_transposed(Transform::Flipped, 1920, 1080),
+            (1920, 1080)
+        );
     }
 
     #[test]
     fn transpose_flipped90_swaps() {
-        assert_eq!(transpose_if_transform_transposed(Transform::Flipped90, 1920, 1080), (1080, 1920));
+        assert_eq!(
+            transpose_if_transform_transposed(Transform::Flipped90, 1920, 1080),
+            (1080, 1920)
+        );
     }
 
     #[test]
     fn transpose_flipped180_no_swap() {
-        assert_eq!(transpose_if_transform_transposed(Transform::Flipped180, 1920, 1080), (1920, 1080));
+        assert_eq!(
+            transpose_if_transform_transposed(Transform::Flipped180, 1920, 1080),
+            (1920, 1080)
+        );
     }
 
     #[test]
     fn transpose_flipped270_swaps() {
-        assert_eq!(transpose_if_transform_transposed(Transform::Flipped270, 1920, 1080), (1080, 1920));
+        assert_eq!(
+            transpose_if_transform_transposed(Transform::Flipped270, 1920, 1080),
+            (1080, 1920)
+        );
     }
 
     // ── fit_inside_bounds ─────────────────────────────────────────
 
     #[test]
     fn fit_inside_already_fits() {
-        let rect = Rect { x: 10, y: 20, w: 100, h: 50 };
+        let rect = Rect {
+            x: 10,
+            y: 20,
+            w: 100,
+            h: 50,
+        };
         let result = fit_inside_bounds(rect, 1920, 1080);
         assert_eq!(result, rect);
     }
 
     #[test]
     fn fit_inside_clips_right_and_bottom() {
-        let rect = Rect { x: 1800, y: 1000, w: 200, h: 200 };
+        let rect = Rect {
+            x: 1800,
+            y: 1000,
+            w: 200,
+            h: 200,
+        };
         let result = fit_inside_bounds(rect, 1920, 1080);
-        assert_eq!(result, Rect { x: 1800, y: 1000, w: 120, h: 80 });
+        assert_eq!(
+            result,
+            Rect {
+                x: 1800,
+                y: 1000,
+                w: 120,
+                h: 80
+            }
+        );
     }
 
     #[test]
     fn fit_inside_clips_negative_origin() {
-        let rect = Rect { x: -50, y: -30, w: 200, h: 200 };
+        let rect = Rect {
+            x: -50,
+            y: -30,
+            w: 200,
+            h: 200,
+        };
         let result = fit_inside_bounds(rect, 1920, 1080);
-        assert_eq!(result, Rect { x: 0, y: 0, w: 150, h: 170 });
+        assert_eq!(
+            result,
+            Rect {
+                x: 0,
+                y: 0,
+                w: 150,
+                h: 170
+            }
+        );
     }
 
     #[test]
     fn fit_inside_completely_out_of_bounds() {
-        let rect = Rect { x: 2000, y: 2000, w: 100, h: 100 };
+        let rect = Rect {
+            x: 2000,
+            y: 2000,
+            w: 100,
+            h: 100,
+        };
         let result = fit_inside_bounds(rect, 1920, 1080);
-        assert_eq!(result, Rect { x: 1920, y: 1080, w: 0, h: 0 });
+        assert_eq!(
+            result,
+            Rect {
+                x: 1920,
+                y: 1080,
+                w: 0,
+                h: 0
+            }
+        );
     }
 
     #[test]
     fn fit_inside_zero_size_rect() {
-        let rect = Rect { x: 100, y: 100, w: 0, h: 0 };
+        let rect = Rect {
+            x: 100,
+            y: 100,
+            w: 0,
+            h: 0,
+        };
         let result = fit_inside_bounds(rect, 1920, 1080);
-        assert_eq!(result, Rect { x: 100, y: 100, w: 0, h: 0 });
+        assert_eq!(
+            result,
+            Rect {
+                x: 100,
+                y: 100,
+                w: 0,
+                h: 0
+            }
+        );
     }
 
     #[test]
     fn fit_inside_zero_bounds() {
-        let rect = Rect { x: 0, y: 0, w: 100, h: 100 };
+        let rect = Rect {
+            x: 0,
+            y: 0,
+            w: 100,
+            h: 100,
+        };
         let result = fit_inside_bounds(rect, 0, 0);
-        assert_eq!(result, Rect { x: 0, y: 0, w: 0, h: 0 });
+        assert_eq!(
+            result,
+            Rect {
+                x: 0,
+                y: 0,
+                w: 0,
+                h: 0
+            }
+        );
     }
 }

tests/integration_test.rs

@@ -44,10 +44,7 @@ fn test_rejects_invalid_args() {
         .output()
         .expect("failed to execute wl-webrtc with invalid args");
 
-    assert!(
-        !output.status.success(),
-        "should reject unrecognized flag"
-    );
+    assert!(!output.status.success(), "should reject unrecognized flag");
     let stderr = String::from_utf8_lossy(&output.stderr);
     assert!(
         stderr.to_lowercase().contains("error")
@@ -68,10 +65,7 @@ fn test_rejects_hevc_codec() {
         .expect("failed to execute wl-webrtc --codec hevc");
 
     // MVP only supports h264; hevc should be rejected.
-    assert!(
-        !output.status.success(),
-        "should reject hevc codec in MVP"
-    );
+    assert!(!output.status.success(), "should reject hevc codec in MVP");
 }
 
 /// Tests requiring a live Wayland compositor and VAAPI hardware.