# Roadmap

This is the canonical order of work, not proof that a feature exists. **A step is not ready for implementation until its user-visible and architectural behavior is documented in the canonical docs.** Update [UX](UX.md), [architecture](ARCHITECTURE.md), and the relevant packaging/upstream documents before changing behavior. Record validation and limitations when the step closes.

| Step | State | Goal |
| --- | --- | --- |
| STEP20A | DONE | Native compositor foundation |
| STEP20B | EXPERIMENTAL | First scrollable runtime row |
| STEP20C | NEXT | Viewport and multi-output correctness |
| STEP20D | PLANNED | Multiple runtime rows |
| STEP20E | PLANNED | Session V2 persistence |
| STEP20F | PLANNED | QuickShell visualization |
| STEP20G | PLANNED | Package and daily-use qualification |

## STEP20A — native foundation · DONE

**Deliverables:** native layout enum/parser, workspace-local state, real tiled Row 0, insertion/removal/focus model, IPC exposure, isolated build/staging, headless tests. **Exit evidence:** [historical report](STEP20A.md) and current source/tests. **Documentation before implementation:** original architecture, upstream base, and package coexistence contract; current canonical versions are [Architecture](ARCHITECTURE.md), [Upstream](UPSTREAM.md), and [Packaging](PACKAGING.md).

## STEP20B — first scrollable row · EXPERIMENTAL

**Deliverables:** logical horizontal geometry, bounded `scroll_x`, scene translation, focus visibility, workspace-local standard-layout toggle, headless visual evidence, patch export. **Exit evidence:** [historical report](STEP20B.md). The single-row proof is present, but it is not a general-use viewport guarantee. **Documentation before further implementation:** [UX](UX.md) and [Architecture](ARCHITECTURE.md) must keep the temporary sizing and scene boundaries explicit.

## STEP20C — viewport correctness · NEXT

**Goal:** make the single-row viewport correct at workspace and output boundaries. **Planned deliverables:** clipping or an equivalent rendering strategy, matching hit testing, adjacent-output tests, resize/migration tests, and transaction-safe camera animation. **Exit criteria:** no cross-output visual/input leakage in the tested scenarios; camera and IPC remain consistent across transactions; standard layouts still pass. **Docs first:** review the [STEP20C viewport proposal](design/STEP20C_VIEWPORT_DESIGN.md), resolve the visual/input gaps found by the [PARTIALLY FEASIBLE isolated probe](design/STEP20C_FEASIBILITY_PROBE.md) and the [PARTIALLY FEASIBLE SceneFX subtree spike](design/STEP20C_SCENEFX_CLIPPING_SPIKE.md), then settle the resulting contract in Architecture and UX and update Known Limitations before implementation. The subtree spike proves a narrow tiled path but exposes a popup visual/input leak and unresolved damage, effect and package-maintenance gates. The [PARTIALLY_FEASIBLE popup ownership probe](design/STEP20C_POPUP_OWNERSHIP_PROBE.md) closes the sampled root/nested popup leak in an isolated build. The later [PARTIALLY_FEASIBLE valid-grab and hidden-owner probe](design/STEP20C_VALID_GRAB_HIDDEN_OWNER_PROBE.md) measures a real XDG grab and exposes a hidden-owner leak in that initial private clip; a further private guard closes the sampled leak. The later nested valid-grab probe closes only its sampled horizontal matrix; the separate vertical probe covers sampled Y-crossing popups. Further output geometries, transaction/output migration, complete damage/effects and packaging remain unresolved. None of these probes authorizes production STEP20C development or general multi-output support.

The [source fixture for the valid-grab probe](../tooling/probes/step20c-valid-grab/README.md) preserves a bounded replay path. Its existence does not change STEP20C's **NEXT** status or any exit criterion.

The [nested valid-grab probe](design/STEP20C_NESTED_VALID_GRAB_PROBE.md) is
**FEASIBLE within its sampled horizontal headless matrix**: distinct valid
grabs for parent and child popups, visual/input clipping, outside dismissal,
hidden-owner camera return and standard-layout return were measured in a
disposable guarded binary. Its [source fixture](../tooling/probes/step20c-nested-grab/README.md)
is reproducible. The next bounded feasibility test should change output
geometry with the same nested grabbed hierarchy and direct control comparison.
Transaction, resize/migration, damage/effects and ABI/package gates remain
open; this result does not change STEP20C's **NEXT** status.

The [vertical-output nested-grab probe](design/STEP20C_VERTICAL_OUTPUT_NESTED_GRAB_PROBE.md)
is **FEASIBLE within its sampled stacked-headless matrix**: both standard
controls produced real Y-crossing A/B popup pixels and button targets, while
the disposable guarded Mosaic build excluded sampled lower popup pixels/hits
and preserved upper interaction, hidden-owner return and standard-layout
return. Its [source fixture](../tooling/probes/step20c-vertical-grab/README.md)
also reproduced the horizontal B-crossing control. The separate negative-origin
comparison is recorded below. Scaling, rotation,
resize/migration, transaction generations, complete damage/effects and
dependency maintenance remain open. STEP20C stays **NEXT**.

The [negative-origin nested-grab probe](design/STEP20C_NEGATIVE_ORIGIN_NESTED_GRAB_PROBE.md)
is **FEASIBLE within its sampled signed-coordinate headless matrix**:
HEADLESS-1 remained at `x=-800`, the virtual pointer reached both outputs,
standard controls proved A/B crossing pixels and buttons, and the private
guarded Mosaic build clipped sampled right-output pixels and hits. Hidden
owner and `splith` return passed. Its [source fixture](../tooling/probes/step20c-negative-origin/README.md)
preserves replay. Scaling, rotation, resize/migration, transaction
generations, complete damage/effects and dependency maintenance remain open.
STEP20C stays **NEXT**.

The [temporal damage probe](design/STEP20C_TEMPORAL_DAMAGE_PROBE.md) is
**PARTIALLY_FEASIBLE**: repeated XDG lifecycle and camera transitions restored
sampled private Mosaic pixels and standard controls, and time-ordered private
damage extents covered changed pixels between sampled captures. It did not
identify every presented frame or bind camera/clip/input to a native applied
transaction generation. Its [source fixture](../tooling/probes/step20c-temporal-damage/README.md)
remains experimental. Its proposed headless presentation-event gate was
examined by the subsequent probe below. Scaling, rotation,
resize/migration, complete effects and dependency
maintenance remain open. STEP20C stays **NEXT**.

The [presentation identity probe](design/STEP20C_PRESENTATION_IDENTITY_PROBE.md)
is **PARTIALLY_FEASIBLE**: native wlroots 0.20.2 headless present events
were paired to commits by `(output, commit_seq)` and applied scene/clip
snapshots were taken at the commit callback. Settled target states passed
sampled clipping and input checks; faster commands could coalesce or defer.
The actual buffer content of each commit and frame-specific pointer relation
remain unproven. Its [private source fixture](../tooling/probes/step20c-presentation-identity/README.md)
does not enter the production build. Its then-open buffer identity gate was
examined by the subsequent private probe below. Scaling, rotation,
migration/resize, complete effects/damage and SceneFX maintenance remain
open. STEP20C stays **NEXT**.

The [output buffer identity probe](design/STEP20C_OUTPUT_BUFFER_IDENTITY_PROBE.md)
is **PARTIALLY_FEASIBLE** in this fixed matrix: 32 real GBM output-state
buffers were read through FX texture APIs, correlated with native commits
and headless presents. Twenty-eight were released on present and four
early because HEADLESS-2 repaint reached a global release in the private
instrumentation; the latter were not retained through present. Three
second reads were byte-identical. Sampled
popup pixels matched the applied scene/clip across
three pairs with the same A/B popup objects; the initial logical/applied
camera lag also had an identified buffer but no proven visual defect.
Readback materially changed timing, and neither frame-specific pointer
identity nor an atomic scene/input generation is proven. Its
[private fixture](../tooling/probes/step20c-buffer-identity/README.md) is
preserved experimental source, not a production dependency. The smallest
next gate is a lower-impact buffer observation with an explicit applied
scene/input generation, then separate effects/damage and SceneFX maintenance
qualification. STEP20C stays **NEXT**.

The [applied state/input probe](design/STEP20C_APPLIED_STATE_INPUT_PROBE.md)
is **PARTIALLY_FEASIBLE** in its fixed headless matrix. A distinct private
patch prevented the historical cross-output buffer release; three
selected buffers were read and retained through native headless present,
while a partial experimental epoch and real pointer traces exposed
applied state at build and hit. Client delivery under grabs remained a
separate observation. Incomplete mutation coverage, untested error paths
and intrusive readback leave the temporal-consistency gate open. The
next experiment was to map the mutation boundary with lower-impact
observation before any production STEP20C decision. STEP20C
stays **NEXT**; multi-output remains **NOT YET SUPPORTED**.

The [mutation coverage probe](design/STEP20C_MUTATION_COVERAGE_PROBE.md)
is **PARTIALLY_FEASIBLE** overall. A bounded trace-only matrix separated
camera/clip, popup hierarchy, same-size client content and surface input
region changes. The input-region test changed the actual scene hit while
`asi_applied_epoch` was unchanged, so that counter is not a complete
geometry/hit identity. Output destruction released one held reference in
the real private compositor; rejected-commit cleanup is still untested on
a backend. Whether SwayFX's existing event-loop ordering suffices for
build/present/input coherence is **UNDECIDED**. The smallest next gate is
a controlled hit-geometry mutation between one known output-state build
and its deferred headless present, with hits and client delivery sampled
on both sides. This remains scientific evidence, not production STEP20C.

The independently replayed [commit/present/input ordering probe](design/STEP20C_COMMIT_PRESENT_INPUT_ORDERING_PROBE.md)
tested that gate without changing backend scheduling. Twenty real input
region mutations applied in two private modes, but none occurred between
an accepted output commit and its matching headless present; P2 is
**INCONCLUSIVE**. The sampled hit and client delivery matched effective
input state, and no distinct Mosaic clipping defect was reproduced. Before
deciding whether an extra generation contract is necessary, the smallest
next gate is passive event-loop phase tracing with a client request already
pending during ordinary repaint, then a same-interval hit if naturally
observable. STEP20C remains **NEXT** and multi-output **NOT YET SUPPORTED**.

The bounded [event-loop pending-input probe](design/STEP20C_EVENT_LOOP_PENDING_INPUT_PROBE.md)
decoupled normal client submission from IPC/client acknowledgements, then
stopped after five attempts in each private mode. All 20 target mutations
applied, with no matching commit-to-present interleaving. Close this
particular temporal line as **INCONCLUSIVE / NOT EXERCISED** for the tested
headless backend and fixed geometry. Do not infer an extra generation
contract or production readiness. The next separate STEP20C gate should
address complete effects/damage, scaling, or resize/migration. STEP20C stays
**NEXT** and multi-output Mosaic **NOT YET SUPPORTED**.

## STEP20D — multi-row Spatial Canvas · PLANNED

**Goal:** connect rows to runtime tree, transactions, scene, input, and IPC. **Planned deliverables:** active-row navigation, row-local scroll/focus, deterministic insertion/reflow, in-row reorder, and between-row movement. **Exit criteria:** real tiled containers preserve identity and order across row changes; focus and camera restore correctly; headless multi-row tests pass. **Docs first:** settle exact interactions and row invariants in UX and Architecture. Unset key combinations remain TBD.

## STEP20E — Session V2 persistence · PLANNED

**Goal:** restore Mosaic workspaces across sessions without creating a second runtime authority. **Planned deliverables:** durable activation, row order/membership, active row, scroll, focus, stable identities, and restart tests. **Exit criteria:** deterministic restore and safe fallback for missing windows/older snapshots. **Docs first:** specify persistence identity, versioning, failure handling, and ownership in Architecture and UX.

## STEP20F — QuickShell visualization · PLANNED

**Goal:** expose compositor-owned Mosaic state in the desktop UI. **Planned deliverables:** workspace/row view and optional layout indication without duplicate QML layout state. **Exit criteria:** UI reflects IPC state and cannot contradict the compositor. **Docs first:** specify IPC consumer behavior and UI interactions in Architecture and UX.

## STEP20G — package and daily-use qualification · PLANNED

**Goal:** publish a validated optional session while preserving standard SwayFX fallback. **Planned deliverables:** final Arch package, optional distinct session entry, install/rollback instructions, and a forward port proven against a newer SwayFX release. **Exit criteria:** package file ownership and coexistence verified, release build and headless/live qualification recorded, standard SwayFX updates remain independent. **Docs first:** update Packaging, Upstream, Development, UX, and Known Limitations with the intended release contract.