feat(client/input): desktop (absolute) mouse mode — remote-desktop sweep M1

New physical-mouse model beside capture: Desktop leaves the pointer
uncaptured and sends absolute positions through the letterbox
(MouseMoveAbs — every host injector already consumes it). Capture
stays the default and the game model.

- pf-client-core: MouseMode (capture|desktop) persisted in Settings,
  default capture so existing stores are unchanged.
- pf-presenter: Capture grows a desktop model — latest-wins pending
  abs position coalesced per loop iteration (same 1000 Hz discipline
  as relative), flushed before clicks/keys/wheel so they land where
  the cursor is; Ctrl+Alt+Shift+M flips the model live; local cursor
  stays hidden over the window (the host's composited cursor is the
  one you see until the M2 cursor channel); Windows keyboard grab
  only engages for capture (a desktop stream is something you
  Alt-Tab away from).
- gamescope gating: its EIS is relative-only, so desktop mode is
  pinned off there (resolved_compositor), with a log note.
- Settings surfaces: GTK row (dynamic caption), WinUI combo,
  console-UI row + step test, capture-hint line.

Verified: fmt + clippy -D warnings + tests (33/40/19) on Linux .21;
clippy -D warnings for all five crates incl. punktfunk-client-windows
native on .173.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

clients/linux/src/ui_settings.rs

@@ -69,6 +69,14 @@ const TOUCH_MODE_CAPTIONS: &[&str] = &[
     "The cursor jumps to your finger — a tap clicks there",
     "Real multi-touch reaches the host — for touch-native apps",
 ];
+/// Physical-mouse model values (persisted) + labels + dynamic captions — same idiom as
+/// the touch rows. Ctrl+Alt+Shift+M flips the model live in-stream.
+const MOUSE_MODES: &[&str] = &["capture", "desktop"];
+const MOUSE_MODE_LABELS: &[&str] = &["Capture (games)", "Desktop (absolute)"];
+const MOUSE_MODE_CAPTIONS: &[&str] = &[
+    "Pointer locks to the stream — relative motion, best for games",
+    "Pointer moves freely in and out — best for remote desktop work",
+];
 
 /// punktfunk's own license (MIT OR Apache-2.0), shown on the About dialog's Legal page.
 const APP_LICENSE: &str = concat!(
@@ -542,6 +550,20 @@ pub fn show(
             set_row_subtitle(&w, TOUCH_MODE_CAPTIONS[i]);
         });
     }
+    let mouse_row = ChoiceRow::new(
+        &dialog,
+        inline,
+        "Mouse input",
+        MOUSE_MODE_CAPTIONS[0],
+        MOUSE_MODE_LABELS,
+    );
+    {
+        let w = mouse_row.widget().clone();
+        mouse_row.connect_changed(move |i| {
+            let i = (i as usize).min(MOUSE_MODE_CAPTIONS.len() - 1);
+            set_row_subtitle(&w, MOUSE_MODE_CAPTIONS[i]);
+        });
+    }
     let inhibit_row = adw::SwitchRow::builder()
         .title("Capture system shortcuts")
         .subtitle("Forward Alt+Tab, Super, … to the host while input is captured")
@@ -718,6 +740,12 @@ pub fn show(
         touch_row.set_selected(touch_i as u32);
         // set_selected never fires the changed hook, so seed the dynamic caption directly.
         set_row_subtitle(touch_row.widget(), TOUCH_MODE_CAPTIONS[touch_i]);
+        let mouse_i = MOUSE_MODES
+            .iter()
+            .position(|&m| m == s.mouse_mode)
+            .unwrap_or(0);
+        mouse_row.set_selected(mouse_i as u32);
+        set_row_subtitle(mouse_row.widget(), MOUSE_MODE_CAPTIONS[mouse_i]);
         let comp_i = COMPOSITORS
             .iter()
             .position(|&c| c == s.compositor)
@@ -788,6 +816,7 @@ pub fn show(
     touch_group.add(touch_row.widget());
     // Group titles are Pango markup — the ampersand must be an entity.
     let kbm_group = group("Keyboard & mouse", "");
+    kbm_group.add(mouse_row.widget());
     kbm_group.add(&inhibit_row);
     kbm_group.add(&invert_row);
     input.add(&touch_group);
@@ -867,6 +896,8 @@ pub fn show(
         }
         s.touch_mode =
             TOUCH_MODES[(touch_row.selected() as usize).min(TOUCH_MODES.len() - 1)].to_string();
+        s.mouse_mode =
+            MOUSE_MODES[(mouse_row.selected() as usize).min(MOUSE_MODES.len() - 1)].to_string();
         s.forward_pad = chosen_pin.borrow().clone();
         s.compositor = COMPOSITORS[(compositor_row.selected() as usize).min(COMPOSITORS.len() - 1)]
             .to_string();

clients/session/src/console.rs

@@ -158,6 +158,7 @@ pub fn run(target: Option<&str>) -> u8 {
             v => v,
         },
         touch_mode: settings_at_start.touch_mode(),
+        mouse_mode: settings_at_start.mouse_mode(),
         invert_scroll: settings_at_start.invert_scroll,
         json_status,
         on_connected: Some(Box::new(move |fingerprint: [u8; 32]| {

clients/session/src/main.rs

@@ -429,6 +429,7 @@ mod session_main {
                 v => v,
             },
             touch_mode: settings.touch_mode(),
+            mouse_mode: settings.mouse_mode(),
             invert_scroll: settings.invert_scroll,
             json_status: true,
             on_connected: Some(Box::new(|fingerprint: [u8; 32]| {

clients/windows/src/app/settings.rs

@@ -90,6 +90,13 @@ const TOUCH_MODES: &[(&str, &str)] = &[
     ("pointer", "Direct pointer"),
     ("touch", "Touch passthrough"),
 ];
+/// Physical-mouse presets: `(stored value, display label)` — capture (pointer lock,
+/// relative, for games) vs desktop (uncaptured absolute pointer, for remote desktop
+/// work). Ctrl+Alt+Shift+M flips the model live in-stream.
+const MOUSE_MODES: &[(&str, &str)] = &[
+    ("capture", "Capture (games)"),
+    ("desktop", "Desktop (absolute)"),
+];
 /// Host compositor presets: `(stored value, display label)`. Advisory — the host falls back to
 /// auto-detect when the choice is unavailable. Only meaningful against a Linux host.
 const COMPOSITORS: &[(&str, &str)] = &[
@@ -394,6 +401,10 @@ pub(crate) fn settings_page(
     let touch_combo = setting_combo(ctx, "Touch input", touch_names, touch_i, |s, i| {
         s.touch_mode = TOUCH_MODES[i].0.to_string();
     });
+    let (mouse_names, mouse_i) = presets(MOUSE_MODES, |v| *v == s.mouse_mode);
+    let mouse_combo = setting_combo(ctx, "Mouse input", mouse_names, mouse_i, |s, i| {
+        s.mouse_mode = MOUSE_MODES[i].0.to_string();
+    });
     let invert_scroll_toggle =
         setting_toggle(ctx, "Invert scroll direction", s.invert_scroll, |s, on| {
             s.invert_scroll = on
@@ -542,6 +553,13 @@ pub(crate) fn settings_page(
             out.extend(group(
                 Some("Keyboard & mouse"),
                 vec![
+                    described(
+                        mouse_combo,
+                        "Capture locks the pointer to the stream and sends relative motion — \
+                         best for games. Desktop leaves the pointer free to enter and leave \
+                         the stream and sends absolute positions — best for remote desktop \
+                         work. Ctrl+Alt+Shift+M switches live.",
+                    ),
                     described(
                         shortcuts_toggle,
                         "Alt+Tab, the Windows key and friends reach the host while the stream \

crates/pf-client-core/src/trust.rs

@@ -456,6 +456,48 @@ impl TouchMode {
     }
 }
 
+/// How a physical mouse drives the host — the desktop-sweep mouse model
+/// (design/remote-desktop-sweep.md M1). Stored stringly in [`Settings::mouse_mode`] so the
+/// file stays readable; parsed with [`MouseMode::from_name`].
+#[derive(Clone, Copy, PartialEq, Eq, Debug)]
+pub enum MouseMode {
+    /// Pointer lock (relative deltas, hidden cursor) — the game model, and the default:
+    /// the only cursor you see is the host's.
+    Capture,
+    /// Absolute pointer, uncaptured: the cursor enters and leaves the stream freely and
+    /// motion goes on the wire as absolute positions through the letterbox. The remote
+    /// desktop model. Requires a host injector with absolute support (not gamescope).
+    Desktop,
+}
+
+impl MouseMode {
+    /// Cycle/picker order (also the settings pickers' option order).
+    pub const ALL: [MouseMode; 2] = [MouseMode::Capture, MouseMode::Desktop];
+
+    /// Parse the persisted name, defaulting to `Capture` for unset/unknown values.
+    pub fn from_name(s: &str) -> MouseMode {
+        match s {
+            "desktop" => MouseMode::Desktop,
+            _ => MouseMode::Capture,
+        }
+    }
+
+    /// The persisted name (the inverse of [`from_name`](Self::from_name)).
+    pub fn as_name(self) -> &'static str {
+        match self {
+            MouseMode::Capture => "capture",
+            MouseMode::Desktop => "desktop",
+        }
+    }
+
+    pub fn label(self) -> &'static str {
+        match self {
+            MouseMode::Capture => "Capture (games)",
+            MouseMode::Desktop => "Desktop (absolute)",
+        }
+    }
+}
+
 /// App settings, persisted as JSON. Stringly-typed gamepad/compositor prefs so the file
 /// stays readable; parsed with `*Pref::from_name` at connect time.
 #[derive(Clone, Serialize, Deserialize)]
@@ -490,6 +532,12 @@ pub struct Settings {
     /// stores load as trackpad.
     #[serde(default = "default_touch_mode")]
     pub touch_mode: String,
+    /// How a physical mouse drives the host: a [`MouseMode`] name — `"capture"` (default,
+    /// pointer lock + relative) or `"desktop"` (uncaptured absolute pointer). Read at
+    /// connect via [`Settings::mouse_mode`]. `default` so pre-existing stores load as
+    /// capture — today's behavior.
+    #[serde(default = "default_mouse_mode")]
+    pub mouse_mode: String,
     /// Grab compositor shortcuts (Alt+Tab, Super…) while input is captured.
     pub inhibit_shortcuts: bool,
     /// Stream the default microphone to the host's virtual mic source.
@@ -577,6 +625,10 @@ fn default_touch_mode() -> String {
     "trackpad".into()
 }
 
+fn default_mouse_mode() -> String {
+    "capture".into()
+}
+
 fn default_true() -> bool {
     true
 }
@@ -604,6 +656,10 @@ impl Settings {
         TouchMode::from_name(&self.touch_mode)
     }
 
+    pub fn mouse_mode(&self) -> MouseMode {
+        MouseMode::from_name(&self.mouse_mode)
+    }
+
     /// The `codec` setting as a `quic::CODEC_*` preference bit (`0` = auto).
     pub fn preferred_codec(&self) -> u8 {
         match self.codec.as_str() {
@@ -631,6 +687,7 @@ impl Default for Settings {
             forward_pad: String::new(),
             compositor: "auto".into(),
             touch_mode: "trackpad".into(),
+            mouse_mode: "capture".into(),
             inhibit_shortcuts: true,
             mic_enabled: false,
             audio_channels: 2,

crates/pf-console-ui/src/screens/settings.rs

@@ -10,7 +10,7 @@ use crate::screens::{Ctx, Outbox};
 use crate::theme::{Fonts, DIM, W};
 use crate::widgets::{ListMsg, MenuList, RowSpec};
 use pf_client_core::gamepad::{MenuEvent, MenuPulse};
-use pf_client_core::trust::{StatsVerbosity, TouchMode};
+use pf_client_core::trust::{MouseMode, StatsVerbosity, TouchMode};
 use skia_safe::{Canvas, Rect};
 
 /// Stable row identity — adjust/activate dispatch by id so nothing acts on a stale
@@ -29,10 +29,11 @@ enum RowId {
     Pad,
     PadType,
     Touch,
+    Mouse,
     Stats,
 }
 
-const ROWS: [RowId; 13] = [
+const ROWS: [RowId; 14] = [
     RowId::Resolution,
     RowId::Refresh,
     RowId::Bitrate,
@@ -45,6 +46,7 @@ const ROWS: [RowId; 13] = [
     RowId::Pad,
     RowId::PadType,
     RowId::Touch,
+    RowId::Mouse,
     RowId::Stats,
 ];
 
@@ -251,6 +253,7 @@ fn row_spec(id: RowId, ctx: &Ctx) -> RowSpec {
             "Touch mode",
             s.touch_mode().label().into(),
         ),
+        RowId::Mouse => (None, "Mouse mode", s.mouse_mode().label().into()),
         RowId::Stats => (
             Some("Interface"),
             "Statistics overlay",
@@ -292,6 +295,11 @@ fn detail(id: RowId) -> &'static str {
             "How the touchscreen drives the host: Trackpad (relative cursor), \
              Direct pointer (cursor jumps to your finger), or Touch passthrough (raw contacts)."
         }
+        RowId::Mouse => {
+            "How a physical mouse drives the host: Capture locks the pointer (relative, \
+             for games), Desktop leaves it free and sends absolute positions. \
+             Ctrl+Alt+Shift+M switches live while streaming."
+        }
         RowId::Stats => {
             "How much the overlay shows: Compact (one line) → Normal → Detailed. \
              Ctrl+Alt+Shift+S cycles it live while streaming."
@@ -367,6 +375,11 @@ fn adjust(id: RowId, delta: i32, wrap: bool, ctx: &mut Ctx) -> bool {
             step_option(cur, TouchMode::ALL.len(), delta, wrap)
                 .map(|i| s.touch_mode = TouchMode::ALL[i].as_name().to_string())
         }
+        RowId::Mouse => {
+            let cur = MouseMode::ALL.iter().position(|m| *m == s.mouse_mode());
+            step_option(cur, MouseMode::ALL.len(), delta, wrap)
+                .map(|i| s.mouse_mode = MouseMode::ALL[i].as_name().to_string())
+        }
         RowId::Stats => {
             let cur = StatsVerbosity::ALL
                 .iter()
@@ -510,6 +523,33 @@ mod tests {
         assert_eq!(ctx.settings.touch_mode, "trackpad");
     }
 
+    #[test]
+    fn mouse_mode_steps_and_wraps() {
+        let (mut settings, pads) = ctx_parts();
+        assert_eq!(settings.mouse_mode, "capture");
+        let library = crate::library::LibraryShared::default();
+        let mut ctx = Ctx {
+            hosts: &[],
+            library: &library,
+            settings: &mut settings,
+            pads: &pads,
+            deck: false,
+            device_name: "t",
+            t: 0.0,
+        };
+        // Capture → Desktop, then a step past the end is a boundary.
+        assert!(
+            !adjust(RowId::Mouse, -1, false, &mut ctx),
+            "already first = thud"
+        );
+        assert!(adjust(RowId::Mouse, 1, false, &mut ctx));
+        assert_eq!(ctx.settings.mouse_mode, "desktop");
+        assert!(!adjust(RowId::Mouse, 1, false, &mut ctx), "last = thud");
+        // A wraps back to the first.
+        assert!(adjust(RowId::Mouse, 1, true, &mut ctx));
+        assert_eq!(ctx.settings.mouse_mode, "capture");
+    }
+
     #[test]
     fn unknown_value_snaps_to_first() {
         let (mut settings, pads) = ctx_parts();

crates/pf-presenter/src/input.rs

@@ -14,10 +14,17 @@
 //! Keys are SDL scancodes → VK via `keymap_sdl`, layout-independent. Motion deltas are
 //! COALESCED: one summed `MouseMove` per loop iteration (a 1000 Hz mouse would
 //! otherwise send a datagram per event).
+//!
+//! The DESKTOP mouse model (design/remote-desktop-sweep.md M1) reuses this same engage/
+//! release state but never locks the pointer: the local cursor moves freely (hidden over
+//! the window — the host's composited cursor is the one you see) and motion goes on the
+//! wire as absolute positions through the letterbox (`MouseMoveAbs`, latest-wins per loop
+//! iteration). Requires a host injector with absolute support — gamescope's EIS is
+//! relative-only, so sessions there are pinned to capture ([`Capture::new`] `abs_ok`).
 
 use crate::keymap_sdl;
 use crate::touch::{Abs, Act, Gestures};
-use pf_client_core::trust::TouchMode;
+use pf_client_core::trust::{MouseMode, TouchMode};
 use punktfunk_core::client::NativeClient;
 use punktfunk_core::input::{InputEvent, InputKind};
 use std::collections::{HashMap, HashSet};
@@ -41,6 +48,13 @@ pub struct Capture {
     held_buttons: HashSet<u32>,
     /// Relative motion not yet on the wire, summed per loop iteration.
     pending_rel: (i32, i32),
+    /// Desktop-model position not yet on the wire, latest-wins per loop iteration.
+    pending_abs: Option<Abs>,
+    /// The desktop (absolute, uncaptured) mouse model is active. Flipped live by the
+    /// Ctrl+Alt+Shift+M chord; never true unless `abs_ok`.
+    desktop: bool,
+    /// The host injector accepts `MouseMoveAbs` (any compositor but gamescope).
+    abs_ok: bool,
     /// Fractional wheel remainder per axis (x, y) in 120-unit WHEEL_DELTA space —
     /// precision surfaces deliver sub-unit deltas; truncating each event drops the tail.
     scroll_acc: (f64, f64),
@@ -70,10 +84,14 @@ fn send(connector: &NativeClient, kind: InputKind, code: u32, x: i32, y: i32, fl
 }
 
 impl Capture {
+    /// `abs_ok` = the host injector accepts absolute pointer events; without it the
+    /// desktop model is unavailable and `mouse_mode` silently resolves to capture.
     pub fn new(
         connector: Arc<NativeClient>,
         touch_mode: TouchMode,
         invert_scroll: bool,
+        mouse_mode: MouseMode,
+        abs_ok: bool,
     ) -> Capture {
         Capture {
             connector,
@@ -82,6 +100,9 @@ impl Capture {
             held_keys: HashSet::new(),
             held_buttons: HashSet::new(),
             pending_rel: (0, 0),
+            pending_abs: None,
+            desktop: abs_ok && mouse_mode == MouseMode::Desktop,
+            abs_ok,
             scroll_acc: (0.0, 0.0),
             touch_slots: HashMap::new(),
             touch_mode,
@@ -94,6 +115,24 @@ impl Capture {
         self.captured
     }
 
+    /// The desktop (absolute, uncaptured) mouse model is active.
+    pub fn desktop(&self) -> bool {
+        self.desktop
+    }
+
+    /// Flip capture ⇄ desktop (the Ctrl+Alt+Shift+M chord). `None` = the host can't take
+    /// absolute pointer events (gamescope), so the chord has nothing to offer; otherwise
+    /// the new desktop state. Motion gathered under the old model never crosses modes.
+    pub fn toggle_desktop(&mut self) -> Option<bool> {
+        if !self.abs_ok {
+            return None;
+        }
+        self.desktop = !self.desktop;
+        self.pending_rel = (0, 0);
+        self.pending_abs = None;
+        Some(self.desktop)
+    }
+
     /// Whether a regained focus should re-engage: yes unless the user released
     /// deliberately (the chord keeps its meaning across an Alt-Tab).
     pub fn should_reengage(&self) -> bool {
@@ -117,6 +156,7 @@ impl Capture {
             return false;
         }
         self.pending_rel = (0, 0); // never flush motion gathered while captured
+        self.pending_abs = None;
         for vk in self.held_keys.drain() {
             send(&self.connector, InputKind::KeyUp, vk as u32, 0, 0, 0);
         }
@@ -132,22 +172,42 @@ impl Capture {
         true
     }
 
-    /// Forward the coalesced motion delta, if any — one datagram per loop iteration.
+    /// Forward the coalesced motion, if any — one datagram per loop iteration. Only one
+    /// of the two stores is ever populated (the run loop routes by [`desktop`](Self::desktop)).
     pub fn flush_motion(&mut self) {
         let (dx, dy) = std::mem::take(&mut self.pending_rel);
         if dx != 0 || dy != 0 {
             send(&self.connector, InputKind::MouseMove, 0, dx, dy, 0);
         }
+        if let Some(a) = self.pending_abs.take() {
+            send(
+                &self.connector,
+                InputKind::MouseMoveAbs,
+                0,
+                a.x,
+                a.y,
+                Self::touch_flags(a.w, a.h),
+            );
+        }
     }
 
     /// Relative motion (SDL relative mouse mode delivers raw deltas while locked).
     pub fn on_motion(&mut self, xrel: f32, yrel: f32) {
-        if self.captured {
+        if self.captured && !self.desktop {
             self.pending_rel.0 += xrel as i32;
             self.pending_rel.1 += yrel as i32;
         }
     }
 
+    /// Desktop-model motion: the cursor's position mapped into the letterboxed content
+    /// rect. Latest-wins — intermediate positions carry no information the final one
+    /// doesn't (unlike deltas, which must sum).
+    pub fn on_motion_abs(&mut self, abs: Abs) {
+        if self.captured && self.desktop {
+            self.pending_abs = Some(abs);
+        }
+    }
+
     pub fn on_key_down(&mut self, sc: sdl3::keyboard::Scancode) {
         if !self.captured {
             return;

crates/pf-presenter/src/run.rs

@@ -20,11 +20,11 @@ use crate::vk::{FrameInput, Presenter};
 use anyhow::{Context as _, Result};
 use pf_client_core::gamepad::GamepadService;
 use pf_client_core::session::{self, SessionEvent, SessionHandle, SessionParams, Stats};
-use pf_client_core::trust::{StatsVerbosity, TouchMode};
+use pf_client_core::trust::{MouseMode, StatsVerbosity, TouchMode};
 use pf_client_core::video::VulkanDecodeDevice;
 use pf_client_core::video::{DecodedFrame, DecodedImage};
 use punktfunk_core::client::NativeClient;
-use punktfunk_core::config::Mode;
+use punktfunk_core::config::{CompositorPref, Mode};
 use sdl3::event::{Event, WindowEvent};
 use sdl3::keyboard::Mod;
 use std::sync::atomic::{AtomicBool, Ordering};
@@ -48,6 +48,11 @@ pub struct SessionOpts {
     /// `Pointer` (absolute cursor), or `Touch` (real multi-touch passthrough). Latched per
     /// session — a mouse-only client leaves this at the default and never sees a finger.
     pub touch_mode: TouchMode,
+    /// Physical-mouse model: `Capture` (pointer lock + relative, the default) or `Desktop`
+    /// (uncaptured absolute pointer — design/remote-desktop-sweep.md M1). Ctrl+Alt+Shift+M
+    /// flips it live; silently resolves to capture on hosts without absolute injection
+    /// (gamescope).
+    pub mouse_mode: MouseMode,
     /// Reverse the scroll direction sent to the host ([`Settings::invert_scroll`]).
     pub invert_scroll: bool,
     /// Emit the `{"ready":true}` stdout line after the first presented frame.
@@ -490,7 +495,7 @@ fn run_inner(mut opts: SessionOpts, mut mode: ModeCtl) -> Result<Option<Outcome>
                     WindowEvent::FocusLost => {
                         if let Some(cap) = stream.as_mut().and_then(|s| s.capture.as_mut()) {
                             if cap.release(false) {
-                                apply_capture(&mut window, &mouse, false);
+                                apply_capture(&mut window, &mouse, false, false);
                                 tracing::info!("focus lost — input released");
                             }
                         }
@@ -501,7 +506,7 @@ fn run_inner(mut opts: SessionOpts, mut mode: ModeCtl) -> Result<Option<Outcome>
                         if let Some(cap) = stream.as_mut().and_then(|s| s.capture.as_mut()) {
                             if cap.should_reengage() {
                                 cap.engage();
-                                apply_capture(&mut window, &mouse, true);
+                                apply_capture(&mut window, &mouse, true, cap.desktop());
                                 tracing::info!("focus gained — input recaptured");
                             }
                         }
@@ -537,20 +542,39 @@ fn run_inner(mut opts: SessionOpts, mut mode: ModeCtl) -> Result<Option<Outcome>
                         if let Some(cap) = stream.as_mut().and_then(|s| s.capture.as_mut()) {
                             if cap.captured() {
                                 cap.release(true);
-                                apply_capture(&mut window, &mouse, false);
+                                apply_capture(&mut window, &mouse, false, false);
                             } else {
                                 cap.engage();
-                                apply_capture(&mut window, &mouse, true);
+                                apply_capture(&mut window, &mouse, true, cap.desktop());
                             }
                             tracing::info!(captured = cap.captured(), "chord: release/engage");
                         }
                         continue;
                     }
+                    // Mouse model flip (capture ⇄ desktop) — applies immediately when
+                    // engaged; a released stream just changes what the next engage does.
+                    if chord && sc == Scancode::M {
+                        if let Some(cap) = stream.as_mut().and_then(|s| s.capture.as_mut()) {
+                            match cap.toggle_desktop() {
+                                Some(desktop) => {
+                                    if cap.captured() {
+                                        apply_capture(&mut window, &mouse, true, desktop);
+                                    }
+                                    tracing::info!(desktop, "chord: mouse mode");
+                                }
+                                None => tracing::info!(
+                                    "chord: mouse mode — host has no absolute pointer \
+                                     (gamescope), staying captured"
+                                ),
+                            }
+                        }
+                        continue;
+                    }
                     if chord && sc == Scancode::D {
                         if let Some(st) = &mut stream {
                             tracing::info!("chord: disconnect");
                             st.request_quit();
-                            apply_capture(&mut window, &mouse, false);
+                            apply_capture(&mut window, &mouse, false, false);
                             // The pump emits Ended(None); the end path routes per mode.
                         }
                         continue;
@@ -583,9 +607,34 @@ fn run_inner(mut opts: SessionOpts, mut mode: ModeCtl) -> Result<Option<Outcome>
                         cap.on_key_up(sc);
                     }
                 }
-                Event::MouseMotion { xrel, yrel, .. } => {
-                    if let Some(cap) = stream.as_mut().and_then(|s| s.capture.as_mut()) {
-                        cap.on_motion(xrel, yrel);
+                Event::MouseMotion {
+                    x, y, xrel, yrel, ..
+                } => {
+                    if let Some(st) = stream.as_mut() {
+                        let video = st.last_video;
+                        if let Some(cap) = st.capture.as_mut() {
+                            if cap.desktop() {
+                                // Desktop model: the cursor's window position through the
+                                // letterbox (same mapping as a pointer-mode finger).
+                                // Before the first decoded frame there is nothing to map
+                                // onto — dropped, like touch.
+                                if let Some(video) = video {
+                                    let (lw, lh) = window.size();
+                                    let nx = x / lw.max(1) as f32;
+                                    let ny = y / lh.max(1) as f32;
+                                    let (ax, ay, aw, ah) =
+                                        finger_to_content(window.size_in_pixels(), video, nx, ny);
+                                    cap.on_motion_abs(Abs {
+                                        x: ax,
+                                        y: ay,
+                                        w: aw,
+                                        h: ah,
+                                    });
+                                }
+                            } else {
+                                cap.on_motion(xrel, yrel);
+                            }
+                        }
                     }
                 }
                 Event::MouseButtonDown { mouse_btn, .. } => {
@@ -593,7 +642,7 @@ fn run_inner(mut opts: SessionOpts, mut mode: ModeCtl) -> Result<Option<Outcome>
                         if !cap.captured() {
                             // The engaging click is suppressed toward the host.
                             cap.engage();
-                            apply_capture(&mut window, &mouse, true);
+                            apply_capture(&mut window, &mouse, true, cap.desktop());
                         } else {
                             cap.on_button_down(mouse_btn);
                         }
@@ -714,7 +763,7 @@ fn run_inner(mut opts: SessionOpts, mut mode: ModeCtl) -> Result<Option<Outcome>
         while escape_rx.try_recv().is_ok() {
             if let Some(cap) = stream.as_mut().and_then(|s| s.capture.as_mut()) {
                 if cap.release(true) {
-                    apply_capture(&mut window, &mouse, false);
+                    apply_capture(&mut window, &mouse, false, false);
                 }
             }
             if fullscreen && !opts.fullscreen {
@@ -727,7 +776,7 @@ fn run_inner(mut opts: SessionOpts, mut mode: ModeCtl) -> Result<Option<Outcome>
             if let Some(st) = &mut stream {
                 tracing::info!("controller chord: disconnect");
                 st.request_quit();
-                apply_capture(&mut window, &mouse, false);
+                apply_capture(&mut window, &mouse, false, false);
             }
         }
 
@@ -818,9 +867,26 @@ fn run_inner(mut opts: SessionOpts, mut mode: ModeCtl) -> Result<Option<Outcome>
                         .ok();
                     gamepad.attach(c.clone());
                     st.clock_offset = Some(c.clock_offset_shared());
-                    let mut cap = Capture::new(c.clone(), opts.touch_mode, opts.invert_scroll);
+                    // gamescope's EIS grants only a relative pointer — absolute sends
+                    // would be dropped, so the desktop model is pinned off there. Auto
+                    // (an older host that didn't say) stays allowed: Windows hosts and
+                    // pre-Welcome-compositor Linux hosts both take absolute.
+                    let abs_ok = c.resolved_compositor != CompositorPref::Gamescope;
+                    if opts.mouse_mode == MouseMode::Desktop && !abs_ok {
+                        tracing::info!(
+                            "desktop mouse mode unavailable on a gamescope host \
+                             (relative-only input) — using capture"
+                        );
+                    }
+                    let mut cap = Capture::new(
+                        c.clone(),
+                        opts.touch_mode,
+                        opts.invert_scroll,
+                        opts.mouse_mode,
+                        abs_ok,
+                    );
                     cap.engage(); // capture engages when the stream starts (ui_stream parity)
-                    apply_capture(&mut window, &mouse, true);
+                    apply_capture(&mut window, &mouse, true, cap.desktop());
                     st.capture = Some(cap);
                     st.connector = Some(c);
                     if let Some(f) = opts.on_connected.as_mut() {
@@ -870,7 +936,7 @@ fn run_inner(mut opts: SessionOpts, mut mode: ModeCtl) -> Result<Option<Outcome>
                         if let Some(st) = stream.take() {
                             st.shutdown();
                         }
-                        apply_capture(&mut window, &mouse, false);
+                        apply_capture(&mut window, &mouse, false, false);
                         if let Some(o) = overlay.as_mut() {
                             // A user-canceled dial ends silently — no error scene.
                             if canceled {
@@ -887,7 +953,7 @@ fn run_inner(mut opts: SessionOpts, mut mode: ModeCtl) -> Result<Option<Outcome>
                     if let Some(cap) = &mut st.capture {
                         cap.release(true);
                     }
-                    apply_capture(&mut window, &mouse, false);
+                    apply_capture(&mut window, &mouse, false, false);
                     match &mode {
                         ModeCtl::Single(_) => break 'main Some(Outcome::Ended(reason)),
                         ModeCtl::Browse(_) => {
@@ -1477,11 +1543,22 @@ impl ResizeIndicator {
 /// with a low-level keyboard hook, the same mechanism the WinUI shell's in-process
 /// client used its own WH_KEYBOARD_LL hooks for. Not engaged on Linux: the compositor
 /// shortcut-inhibit story stays the shells' concern (Settings.inhibit_shortcuts).
-fn apply_capture(window: &mut sdl3::video::Window, mouse: &sdl3::mouse::MouseUtil, on: bool) {
-    mouse.set_relative_mouse_mode(window, on);
+///
+/// The `desktop` mouse model never locks: the pointer roams (and leaves the window)
+/// freely, the local cursor is hidden over the window — the host's composited cursor,
+/// tracking our absolute sends, is the one you see (until the M2 cursor channel flips
+/// who draws it) — and system chords stay local (a remote desktop is something you
+/// Alt-Tab away from, not into). `desktop` only matters while `on`.
+fn apply_capture(
+    window: &mut sdl3::video::Window,
+    mouse: &sdl3::mouse::MouseUtil,
+    on: bool,
+    desktop: bool,
+) {
+    mouse.set_relative_mouse_mode(window, on && !desktop);
     mouse.show_cursor(!on);
     #[cfg(windows)]
-    window.set_keyboard_grab(on);
+    window.set_keyboard_grab(on && !desktop);
 }
 
 /// Is this SDL touch device a real touchscreen (DIRECT, window-relative coordinates)?
@@ -1599,7 +1676,7 @@ struct PresentedWindow {
 
 /// The capture hints (`ui_stream` parity — the words the user reads while released).
 const HINT_KEYBOARD: &str = "Click the stream to capture input · Ctrl+Alt+Shift+Q releases · \
-     Ctrl+Alt+Shift+D disconnects · Ctrl+Alt+Shift+S stats";
+     Ctrl+Alt+Shift+M mouse mode · Ctrl+Alt+Shift+D disconnects · Ctrl+Alt+Shift+S stats";
 const HINT_WITH_PAD: &str = "Click the stream to capture input · Ctrl+Alt+Shift+Q releases · \
      Ctrl+Alt+Shift+D disconnects · hold L1 + R1 + Start + Select to leave";