M.010.17 — Android Foldable Display Split-View XR (Execution Spec)

Date: 2026-04-04
Owner: Copilot execution lane
Status: Ready for implementation

Goal

Enable a foldable-first interaction mode where Android foldables (Galaxy Fold/Flip class) use split-screen layout:

• Viewfinder pane: immersive scene preview
• Control pane: editing/scene controls

This converts foldables into practical mobile XR workstations for authoring and demo workflows.

Product behavior

1. User opens HoloScript mobile session on foldable.
2. Runtime detects fold posture + window class.
3. App switches to split XR layout automatically (or via toggle).
4. Left/top pane renders viewfinder scene; right/bottom pane exposes controls.
5. Edits in control pane apply to viewfinder in real time.

Scope

In scope (v1)

• Foldable capability + posture detection
• Dynamic pane orchestration for split mode
• Real-time control-to-view updates
• Portrait/landscape posture-aware pane ratios
• Graceful fallback on non-foldables

Out of scope (v1)

• Multi-window collaboration across apps
• Full desktop-grade panel docking
• Vendor-specific hinge-angle optimization beyond baseline categories

Architecture

1) Device capability and posture probe

Capture runtime profile:

interface FoldableProfile {
  isFoldable: boolean;
  posture: 'closed' | 'half_open' | 'open' | 'unknown';
  orientation: 'portrait' | 'landscape';
  preferredSplit: 'horizontal' | 'vertical';
  viewfinderRatio: number;
  controlRatio: number;
}

2) Split layout orchestrator

• Establish two rendering surfaces/components:
  • XRViewfinderPane
  • ControlPane
• Shared reactive scene state channel keeps both panes synchronized.

3) Input routing model

• Gesture/input in control pane mutates scene command stream.
• Viewfinder receives command stream and re-renders incrementally.
• Prevent cross-pane gesture collision via pane-scoped hit testing.

4) Fallback behavior

• Non-foldable devices use stacked single-pane mode.
• Foldable unsupported posture falls back to standard mode with prompt.

Proposed code touch points

• packages/studio/ (mobile authoring UI)
  • add foldable split layout container and pane components
• packages/runtime/
  • add posture/capability adapter and synchronized render channel
• packages/core/
  • add split-mode state schema metadata for persistence

Failure taxonomy

• FOLDABLE_PROFILE_UNAVAILABLE
• UNSUPPORTED_POSTURE_TRANSITION
• PANE_SYNC_TIMEOUT
• COMMAND_STREAM_BACKPRESSURE
• VIEWFINDER_RENDER_DEGRADED

Acceptance criteria

1. Foldable device auto-enters split mode in supported posture.
2. Control pane actions reflect in viewfinder under 100ms median local latency.
3. Posture/orientation changes preserve session state without crash.
4. Non-foldable fallback path remains fully functional.
5. Telemetry captures split-mode engagement and failure events.

Test plan

Unit

• foldable profile derivation logic
• pane ratio/orientation calculations
• command routing and pane-scoped input guards

Integration

• split mode activation/deactivation lifecycle
• orientation + posture transition handling
• control-pane mutation -> viewfinder update path

Device validation

• Galaxy Fold open/half-open/closed transitions
• Galaxy Flip posture transitions
• sustained editing session stability and heat/perf checks

Shipping slices

• Slice A: foldable detection + split container
• Slice B: synchronized panes + input routing
• Slice C: transition hardening + telemetry + UX polish

Metrics

• foldable_mode_entry_total
• foldable_mode_active_duration_ms
• pane_sync_latency_ms
• posture_transition_failure_total
• foldable_fallback_activation_total

Definition of done

• Foldable split-view XR authoring works end-to-end on target devices
• acceptance criteria pass
• fallback behavior verified on non-foldable Android
• docs updated with support matrix and posture behavior