RegionEditor DevPlan

Region Editor UI — Dev Plan

Companion pages: Technical Index · Animation Roadmap (Sub-goal B) · Asset Manager Dev Plan (Sub-goal A, deferred) · Regions Guide

Status: SHIPPED (R0–R3). All phases landed, including the R3 "Capture current view" re-frame. Source design: Animation Roadmap §Sub-goal B. Sibling Asset Manager is deferred and will reuse this editor as its Region detail-pane.

---

Problem

Regions are saved (name-prompt dialog) and recalled (combo pick), but cannot be edited in place. To rename a region, retag its curated themes, attach an animation, or drop a stale lighting override, the user must delete and re-save — which forces recapturing the live view geometry and loses any metadata they don't re-enter.

Concretely, HostColorThemeService.SaveCurrentAsRegion always rebuilds the region from the live FractalViewState. There is no path that edits a saved region's metadata while preserving its stored geometry (Center / Zoom / Iterations / QD limbs).

Goal

A real edit-in-place path for saved regions:

• Right-click / "Edit" a region → dialog pre-populated from the saved record, geometry preserved.
• Edit metadata: Name, Description, attached Animation, CuratedThemes whitelist, keep/clear LightingOverride, keep/clear EmbeddedWatermark.
• Geometry (Center, Zoom, Iterations) is not free-text editable — it is shown read-only, with an optional "Capture current view" to re-snap it from the live view (parallels the save flow). (Capture button is a Phase R3 nicety, not required for MVP.)
• Built-in regions are immutable: editing one clones it into a new user-region (user picks a new name), leaving the built-in untouched.

Existing pieces we build on

• FractalRegion — editable metadata fields already exist: Name, Description, AnimationName, CuratedThemes, LightingOverride, EmbeddedWatermark, FractalType.
• FractalRegionLibrary — UserRegions, AddUserRegion, RemoveUserRegion, FindByName, Save. Replace-by-name = remove + add.
• HostColorThemeService — SaveCurrentAsRegion already does replace-by-name + built-in-clobber refusal; EnumerateAnimationNames, EnumerateRegionNames.
• Editor-window pattern: AnimationEditorView / ColorThemeEditorView (modeless Window + VM, launched from ShellViewModel, tracked in MainWindow.axaml.cs). We mirror it.
• Toolbar has a Theme "Edit" button next to the region/theme combos (MainWindow.axaml:115) — we add a Region "Edit" button as the parallel affordance.

---

Phases (each phase = one commit)

Phase R0 — service layer (metadata-preserving edit) ✅

New DTO + two service methods; no UI. Establishes the edit contract and is unit-testable headless.

• New RegionEditModel DTO in Abstractions/Models/ — editable fields plus read-only geometry echo (for display) plus IsBuiltIn / OriginalName.
• IColorThemeService.GetRegionForEdit(string name) : RegionEditModel? — snapshots a saved (or built-in) region into the DTO.
• IColorThemeService.UpdateRegionMetadata(RegionEditModel edits) : RegionUpdateResult — writes metadata back onto the existing user region, preserving its stored geometry; built-in OriginalName → clone to a new user region; refuses name collisions with a different existing region.
• HostColorThemeService implements both against FractalRegionLibrary.
• Tests in Server.Tests: preserve-geometry round-trip, rename, built-in clone-on-edit, name-collision refusal, animation attach/detach.

Phase R1 — editor VM + view ✅

• RegionEditorViewModel (UI.Avalonia/ViewModels) — binds the DTO, exposes animation-name + theme-name pick lists from the service, Save / Cancel commands, validation (non-empty name, collision preflight), keep/clear toggles for lighting + watermark.
• RegionEditorView.axaml (UI.Avalonia/Views) — modeless Window mirroring AnimationEditorView chrome. Read-only geometry block; editable metadata rows; Save/Cancel.

Phase R2 — wire entry point ✅

• Region "Edit" button on the toolbar (parallel to Theme Edit), enabled when a region is selected.
• ShellViewModel.ShowRegionEditor(name) — mirror ShowAnimationEditor: build VM from GetRegionForEdit, wire RegionSavedToLibrary → refresh region combo + reselect, CloseRequested → hide.
• MainWindow.axaml.cs — track the RegionEditorView window instance like _animationEditorWin.
• Built-in selected → editor opens in clone mode (name cleared / suffixed, Save always creates a new user region).
• Entry points: toolbar "Edit" button and a right-click "Edit region…" context-menu item on the toolbar region combo (both fire ShowRegionEditorCommand).

Phase R3 — "Capture current view" ✅

• Button in the editor that re-snaps geometry from the live FractalViewState (reuses the save-flow capture), so users can both retag metadata and update the framing in one edit.
• Service: UpdateRegionMetadata(RegionEditModel, FractalViewState?) overload — when the live state is non-null the region geometry is built from it (BuildGeometryFromLiveState, shared with SaveCurrentAsRegion) instead of preserved via CloneRegionGeometry. Default interface method delegates to the metadata-only overload for back-compat.
• VM: optional Func<FractalViewState?> provider wired by the shell (() => Main.ViewState); CaptureCurrentViewCommand arms a pending re-frame and shows a green banner previewing the live center/zoom. Save passes the pending state through.

---

Risk

Low. Persistence shape unchanged; library already supports add/remove; only a "replace-by-name preserving geometry" service path + one dialog are new. Built-ins stay immutable by construction (clone-on-edit).

Open questions

• CuratedThemes editing UI. Full multi-select vs comma list? Resolved (R1b): checkable list against EnumerateThemeNames with a live substring filter. Curated names no longer in the library are kept (checked) so an edit never silently drops them.
• Rename ripple. Regions are referenced by name from slideshow configs (FilterFractalTypes is by type, not name — low risk) and the toolbar's last-selected. Rename updates the combo; no back-references to rewrite today, but note it here in case slideshow gains by-name region whitelists later.