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).
• Phase 2 common/runtime batch committed and pushed as ade5be3 (Add XCUI runtime screen layer and demo textarea).
• Current work has moved into Phase 3: stabilize schema/validation and continue filling the remaining common/runtime/editor gaps instead of replacing the old editor.
• The current stable editor-layer batch is centered on LayoutLab as the widget proving ground for tree/list/property-section style controls.

Three-Layer Status

1. Common Core

• UI::DrawData, input event types, focus routing, style/theme resolution are in active use.
• UIDocumentCompiler is buildable again after repairing the duplicated schema helper regression introduced by overlapping schema work.
• 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.
• Shared engine-side UIDocumentScreenHost now compiles .xcui / .xctheme screen documents into a runtime-facing document host path instead of leaving all document ownership in new_editor.
• Core regression coverage now includes UIContext, layout, style, runtime screen player/system, and real document-host 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

• 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.
• The demo runtime has moved past single-line input: multiline TextArea behavior is now covered in the sandbox testbed.
• Engine-side runtime ownership is no longer zero: UIScreenPlayer, UIDocumentScreenHost, and UISystem now define a shared runtime contract for loading a screen document, ticking it with input, and collecting UI::UIDrawData.
• UISystem now supports layered screen composition semantics: stacked screen players, top-interactive input routing, and modal layers that block lower screens.

Current gap:

• No production game-loop integration has been wired yet from scene/runtime systems into UISystem.
• The runtime widget library is still shallow and missing the editor-grade controls that will later be shared downward.

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.
• XCUI Demo now covers both single-line and multiline text authoring behavior.
• LayoutLab now includes a ScrollView prototype and a more editor-like three-column authored layout.
• LayoutLab now also covers editor-facing widget prototypes: TreeView, TreeItem, ListView, ListItem, PropertySection, and FieldRow.
• 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 at the shared-module level: the authored prototypes exist, but virtualization, selection models, command routing, property editing models, toolbar/menu chrome, and icon-atlas widgets are not yet extracted into reusable XCUI modules.

Validated This Phase

• new_editor_xcui_demo_runtime_tests: 7/7
• new_editor_xcui_layout_lab_runtime_tests: 6/6
• 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: 14/14
• core_ui_style_tests: 5/5

Landed This Phase

• Demo runtime TextField with UTF-8 text insertion, caret state, and backspace.
• Demo runtime multiline TextArea path in the sandbox and test coverage for caret movement / multiline input.
• Demo authored resources updated to exercise the input field.
• LayoutLab ScrollView prototype with clipping and hover rejection outside clipped content.
• LayoutLab editor-widget prototypes for tree/list/property-style sections with dedicated runtime coverage.
• Engine runtime layer added:
  • UIScreenPlayer
  • UIDocumentScreenHost
  • UISystem
  • layered screen composition and modal blocking semantics
• 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.
• UIDocumentCompiler.cpp repaired enough to restore full local builds after the duplicated schema-helper regression.
• MSVC debug build hardening was tightened again so large parallel engine rebuilds stop tripping over compile-PDB contention.

Phase Risks Still Open

• Schema/validation still needs a clean minimal landing instead of the current partially merged state in UIDocumentCompiler.cpp.
• 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.
• Editor widget coverage is still prototype-driven inside LayoutLab; it has not yet been promoted into a reusable shared widget/runtime layer.

Next Phase

1. Cleanly stabilize schema/validation in UIDocumentCompiler.cpp and add targeted schema regression tests.
2. Expand runtime/game-layer ownership from the current document host + layered UISystem into reusable menu/HUD stack patterns and engine runtime integration.
3. Promote the current editor-facing widget prototypes out of authored LayoutLab content and into reusable XCUI widget/runtime modules, then continue with toolbar/menu and more native shell-owned chrome.
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.