XCEngine/docs/plan/XCUI_Phase_Status_2026-04-05.md

# XCUI Phase Status 2026-04-05

## Scope

Current execution stays inside the XCUI module and `new_editor`.
Old `editor` replacement is explicitly out of scope for this phase.

## Latest Checkpoint

- Phase 1 sandbox batch committed and pushed as `67a28bd` (`Add XCUI new editor sandbox phase 1`).
- Current work has moved into Phase 2: filling the three-layer XCUI structure instead of replacing the old editor.

## Three-Layer Status

### 1. Common Core

- `UI::DrawData`, input event types, focus routing, style/theme resolution are in active use.
- `UIDocumentCompiler` was restored to a stable buildable baseline after a broken parallel schema attempt corrupted the file.
- Build-system hardening for MSVC/PDB output paths has started in root CMake, `engine/CMakeLists.txt`, `new_editor/CMakeLists.txt`, and `tests/NewEditor/CMakeLists.txt`.
- Shared engine-side XCUI runtime scaffolding is now present under `engine/include/XCEngine/UI/Runtime` and `engine/src/UI/Runtime`.
- Core regression coverage now includes `UIContext`, layout, style, and runtime screen-player tests through `core_ui_tests`.

Current gap:

- Schema/validation is not yet landed in a stable form.
- Shared widget/runtime instantiation is still thin and mostly editor-side.
- Common widget primitives are still incomplete: multiline text editing, tree/list virtualization, property-grid composition, and native image/source-rect level APIs.

### 2. Runtime/Game Layer

- Runtime-side XCUI is still shallow.
- The main concrete progress here is that the retained-mode demo runtime now supports a real `TextField` input path with UTF-8 text entry and backspace handling.
- This proves that the runtime-facing layer is no longer limited to static cards/buttons.
- Engine-side runtime ownership is no longer zero: `UIScreenPlayer` and `UISystem` now define a minimal shared runtime contract for loading a screen document, ticking it with input, and collecting `UI::UIDrawData`.

Current gap:

- No real game-facing screen host, menu stack, HUD stack, or shared runtime widget library yet.
- The new runtime layer still needs a real XCUI document host implementation instead of the current host-facing contract only.

### 3. Editor Layer

- `new_editor` remains the isolated XCUI sandbox.
- Native hosted preview is working as `RHI offscreen surface -> ImGui shell texture embed`.
- `XCUI Demo` remains the long-lived effect and behavior testbed.
- `LayoutLab` now includes a `ScrollView` prototype and a more editor-like three-column authored layout.
- Panel diagnostics were expanded to clearly separate preview/runtime/input state and native vs legacy paths.
- `XCNewEditor` builds successfully to `build/new_editor/bin/Debug/XCNewEditor.exe`.

Current gap:

- The shell is still ImGui-hosted.
- Editor-specialized widgets are still incomplete: tree, list virtualization, property grid, toolbar/menu, text area, icon atlas widgets.

## Validated This Phase

- `new_editor_xcui_demo_runtime_tests`: `6/6`
- `new_editor_xcui_layout_lab_runtime_tests`: `5/5`
- `new_editor_xcui_rhi_command_compiler_tests`: `6/6`
- `new_editor_xcui_rhi_render_backend_tests`: `5/5`
- `XCNewEditor` Debug target builds successfully
- `core_ui_tests`: `20/20`

## Landed This Phase

- Demo runtime `TextField` with UTF-8 text insertion, caret state, and backspace.
- Demo authored resources updated to exercise the input field.
- LayoutLab `ScrollView` prototype with clipping and hover rejection outside clipped content.
- RHI image path improvements:
  - clipped image UV adjustment
  - mirrored image UV preservation
  - external texture binding reuse
  - per-batch scissor application
- `new_editor` panel/shell diagnostics improvements for hosted preview state.
- XCUI asset document loading changed to prefer direct source compilation before `ResourceManager` fallback for the sandbox path, fixing the LayoutLab crash.

## Phase Risks Still Open

- Schema/validation work must be restarted cleanly after the corrupted parallel attempt.
- `ScrollView` is still authored/static; no wheel-driven scrolling or virtualization yet.
- `Image` widgets still do not have source-rect/atlas-subregion level API in the high-level draw command model.
- Editor shell still depends on ImGui as host chrome.

## Next Phase

1. Re-open common-layer schema/validation on a clean baseline and land the smallest stable version.
2. Expand runtime/game-layer ownership from `UIScreenPlayer`/`UISystem` into a real XCUI document host plus menu/HUD stack patterns.
3. Add next editor-facing widgets: `TextArea`, list/tree, property-style sections.
4. Move more diagnostics and shell affordances into XCUI-owned editor-layer surfaces instead of only ImGui HUDs.
5. Continue phased validation, commit, push, and plan refresh after each stable batch.