The full Parsec model: launching a game from a desktop session flips the
client into captured relative automatically, and back — no chords.
- Capture overlay now distinguishes 'hidden' from 'no cursor yet':
CursorOverlay grows a visible flag, overlay() returns Some whenever a
bitmap is known (the encode loop strips invisible overlays after
forwarding so no blend path ever draws one; the CPU composite guarded
on visibility already).
- Host forwarder maps it onto the reserved wire bit: visible ⇒ VISIBLE,
hidden-but-known ⇒ RELATIVE_HINT (an app grabbed/hid the pointer),
never any hint before the first bitmap — a cold start can't flip a
desktop session into capture.
- Presenter: edge-triggered auto-flip on hint changes via the new
Capture::set_desktop (chord semantics untouched); a manual ⌃⌥⇧M sets
an override latch that holds until the HOST's intent next changes, so
the hint never fights the user. Leaving relative warps the local
cursor to the host's last pointer position through the new
content_to_window inverse-letterbox mapping (unit-tested against
finger_to_content) — the hand-back is seamless.
Verified on .21: fmt + clippy -D warnings + tests (presenter 20 incl.
the inverse-mapping roundtrip, host 245).
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
The host cursor stops riding the video and becomes a real OS cursor on
the client (the Parsec/RDP model): pointer feel no longer pays the
capture→encode→network→decode→present round trip.
Wire (M2a):
- Hello grows a client_caps trailing byte (CLIENT_CAP_CURSOR) after the
fixed display_hdr block — presence disambiguated by remaining length,
which caps the post-HDR tail at 27 bytes (documented); Welcome answers
HOST_CAP_CURSOR (capable-and-asked, the 444/clipboard precedent).
- CursorShape (0x50, control stream): serial + dims + hotspot + straight
RGBA, ≤120px/side so the u16 frame always fits (128² would overshoot);
client caches by serial — re-showing a known shape costs 14 bytes, not
a bitmap (RDP pointer-cache for free).
- CursorState (0xD0 datagram): serial + visible/relative_hint flags +
position, sent once per encode-loop tick — latest-wins, self-healing
under loss, no refresh timer. relative_hint is reserved for M3.
- Client core: two new planes (control-task + datagram-task arms) →
next_cursor_shape/next_cursor_state; connect() grows client_caps
(C ABI passes 0 until the v11 cursor poll fns exist).
Host (M2b, Linux portal only):
- handshake::cursor_forward is THE predicate (client asked ∧ Linux ∧
compositor ≠ gamescope) — Welcome bit and session wiring both read it.
- SessionPlan.cursor_blend goes false for a forwarding session; the
encode loop ticks a CursorForwarder every iteration: shape-serial diff
→ control-task bridge (mirrors probe_result), state datagram → conn.
- CursorOverlay/capture CursorState carry the hotspot through
(nearest-neighbor downscale backstop for XL cursors, unit-tested).
Presenter:
- CursorChannel drains both planes per loop iteration; shapes become
SDL color cursors (from_surface + hotspot), applied while the desktop
mouse model is engaged; visibility follows the host; capture/released
hands back the system cursor. Sessions advertise the cap when they
START in desktop mode.
Verified on .21: fmt + clippy -D warnings (7 crates) + tests green
(core 218 incl. new wire roundtrips, host 245 incl. e2e + forwarder
downscale tests).
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
enricobuehlerandClaude Fable 5