---
id: PLN-0082
ticket: render-frame-packet-boundary
title: Frame Publication and Present Boundary
status: done
created: 2026-05-25
ref_decisions: [DEC-0030]
tags: [gfx, renderer, runtime, frame-composer, architecture, ui, pipeline]
---

## Briefing

Source decision: `DEC-0030`.

Move `present()` and surface publication behind the render-surface implementation boundary so runtime producers no longer publish buffers directly.

## Target

Only the render-surface implementation publishes RGBA8888 output; logical producers and `RenderManager` hand off closed submissions through a boundary.

## Scope

- Identify all direct `present()` and surface publication callsites.
- Define the render-surface adapter boundary.
- Route publication through the adapter from `RenderManager`.
- Keep desktop `pixels` publication as a host implementation detail.
- Preserve frame pacing and invalidation behavior.

## Out of Scope

- New backend registry.
- GPU implementation.
- Render thread.
- Dirty regions.
- Visual transition design.

## Execution Sequence

1. Inventory `present()`, framebuffer publication, and host invalidation callsites.
2. Add or refine a render-surface trait/adapter that consumes `RenderSubmission`.
3. Move host desktop publication below that adapter.
4. Update runtime frame loop to publish only through `RenderManager` and the adapter.
5. Remove direct publication from composer, `gfx2d`, `gfxui`, Shell, and Game producers.
6. Verify frame pacing and host invalidation still occur at the correct boundary.

## Acceptance Criteria

- Logical render domains cannot call `present()` or publish buffers directly.
- Host desktop publication remains functional below the render-surface boundary.
- `RenderManager` owns the policy for selecting the latest complete submission.
- Existing frame pacing behavior is not regressed.

## Tests / Validation

- Add unit tests for render-surface handoff.
- Add integration tests proving producers cannot publish directly.
- Run host desktop render/pacing tests.
- Inspect `rg -n "present\\(|publish|pixels" crates` for boundary violations.

## Risks

- Publication and invalidation may be coupled in current host code; preserve timing semantics while moving ownership.
- A too-broad adapter can become a backend registry prematurely.

## Affected Artifacts

- Runtime render manager modules
- Host desktop render surface modules
- Frame pacing tests