# canvas mode

orbit's intra-frame component editor. a separate dialog window for fine-tuning the position and styling of individual components within a single frame.

## purpose

when a user double-clicks a frame in edit mode, canvas mode opens a dialog window that renders all of that frame's internal components (text, icons, auras, cast bars) as draggable elements. the user can reposition components, adjust per-component overrides (font, size, color), dock/undock components, and zoom the viewport.

## data flow

```mermaid
graph LR
    SV[(SavedVariables)] -->|read settings| dialog[Canvas Mode Dialog]
    dialog -->|user adjusts| buffer[Pending Overrides]
    buffer -->|staged| txn[Settings Transaction Cache]
    txn -->|CANVAS_SETTINGS_CHANGED| preview[Edit Mode Preview]
    txn -->|Apply| SV
    txn -->|Cancel/ESC| discard((Discard))
    SV -->|ApplySettings| live[Live Frames]
    SV -->|ApplySettings| preview
```

canvas mode reads the same settings as live frames and edit mode. all changes are buffered as pending overrides and staged into the settings transaction cache. the transaction fires `CANVAS_SETTINGS_CHANGED` on each edit, allowing preview frames to live-update without touching saved variables. when the user hits "apply," the transaction commits to saved variables and triggers `ApplySettings` on both live frames and edit mode previews. cancel discards the transaction and restores preview frames to their pre-edit state.

## directory structure

```
CanvasMode/
  CanvasMode.xml          -- xml script bundle (load order)
  CanvasEdit.lua          -- canvas mode engine: enter/exit/toggle, selection tinting, background overlay
  ComponentRegistry.lua   -- component registration, drag mechanics, position callbacks, nudge
  ComponentHandle.lua     -- drag handle creation and pooling for components
  ComponentHelpers.lua    -- safe size/position utilities (WoW 12.0+ secret value handling)
  SnapEngine.lua          -- unified edge-magnet and grid-round snap logic
  SmartGuides.lua         -- visual snap feedback lines (edge/center alignment)
  OverrideUtils.lua       -- per-component override read/write helpers
  Init.lua                -- canvas mode initialization and constants
  SettingsTransaction.lua -- transactional cache for edit sessions (Begin/Commit/Rollback)
  Dialog.lua              -- main dialog window: open/close, tab filtering, frame selection
  DialogActions.lua       -- dialog button handlers (apply, reset, cancel)
  Viewport.lua            -- viewport controls (zoom, pan, sync toggle, preview switching)
  Dock.lua                -- disabled component dock (drag-to-disable, click-to-restore)
  CanvasModeTour.lua      -- guided tour explaining Canvas Mode features
  CanvasModeDrag.lua      -- intra-dialog component drag-and-drop
  ComponentSettings.lua         -- per-component settings core (open/close, value routing, layout)
  ComponentSettingsSchema.lua   -- schema definitions, presets, titles, type detection
  ComponentSettingsWidgets.lua  -- widget creation helpers (slider, checkbox, font, color)
  ComponentSettingsPreview.lua  -- preview renderers (portrait, cast bar, health text) + style applicators
  Creators/               -- component creator registry (how to build draggable previews per type)
    Registry.lua
    AuraCreator.lua
    CastBarCreator.lua
    FontStringCreator.lua
    IconFrameCreator.lua
    PortraitCreator.lua
    StatusIconGroupCreator.lua
    TextureCreator.lua
```

## plugin onboarding contract

### required plugin fields

| field | type | description |
|-------|------|-------------|
| `canvasMode` | `true` | enables canvas mode for this plugin. set on the plugin table. |

### optional plugin fields

| field | type | description |
|-------|------|-------------|
| `supportsGlobalSync` | `boolean` | multi-instance plugins (e.g. ActionBars) where one layout applies to all instances. enables the sync toggle UI. |
| `defaults.ComponentPositions` | `table` | default positions per component key. used by "reset positions" in canvas mode. |
| `defaults.DisabledComponents` | `table` | default disabled component keys. used by "reset positions". |
| `canvasPreviewText` | `{[key] = string}` | per-key preview text shown in canvas mode. supplies realistic worst-case strings (e.g. `Name = "Tyrannothesaurus-Stormrage"`) so users can see how their layout handles long content and overlap. takes precedence over the live source text. |
| `GetCanvasPreviewText(self, key) → string\|nil` | `function` | functional alternative to `canvasPreviewText`. return nil to fall through to defaults. |

### lifecycle hooks (from PluginMixin)

these are already provided by `PluginMixin`. only override if you need plugin-specific behavior.

| hook | default behavior | when to override |
|------|------------------|------------------|
| `OnCanvasApply()` | calls `ApplySettings()` + `SchedulePreviewUpdate()` | group frames that delegate to `GroupCanvasRegistration` |
| `IsComponentDisabled(key)` | checks `DisabledComponents` setting (respects active transaction) | plugins with non-standard disabled storage (e.g. CooldownManager) |
| `GetComponentPositions(sysIdx)` | reads `ComponentPositions` (respects active transaction) | never — use the mixin default |

### settings contract

canvas mode reads and writes these settings keys per `systemIndex`:

| key | type | written by |
|-----|------|------------|
| `ComponentPositions` | `{[key] = {anchorX, anchorY, offsetX, offsetY, justifyH, posX, posY}}` | Apply |
| `DisabledComponents` | `{key, key, ...}` | Apply |
| `UseGlobalTextStyle` | `boolean` | Apply (sync toggle) |
| `GlobalComponentPositions` | same as ComponentPositions | Apply (when synced) |
| `GlobalDisabledComponents` | same as DisabledComponents | Apply (when synced) |

per-component overrides (font, size, color) are written via `ComponentSettings:FlushPendingPluginSettings()`.

### 4-step onboarding

1. **set the flag**: `Plugin.canvasMode = true` on your plugin table
2. **register components**: your plugin's `ApplySettings` must call `PositionUtils.ApplyTextPosition` or equivalent for each positioned component. canvas mode will generate position data that these functions consume.
3. **provide defaults** (optional): set `Plugin.defaults.ComponentPositions` and `Plugin.defaults.DisabledComponents` to enable the "reset positions" button.
4. **add a creator** (only if new component type): register a new creator type in `Creators/` and add it to `Creators/Registry.lua`. existing creators (Aura, CastBar, FontString, IconFrame, Portrait, StatusIconGroup, Texture) are the reference for the contract.

### component key naming

- PascalCase: `HealthText`, `CastBar`, `StatusIcons`
- sub-components use dot notation: `CastBar.Text`, `CastBar.Timer`
- aura containers: `Buffs`, `Debuffs`
- icons: `DefensiveIcon`, `CrowdControlIcon`, `PrivateAuraAnchor`

## rules

- canvas mode code may depend on edit mode infrastructure (`HandleCore`, `Pixel`), never on specific plugins
- all color constants for the dock and dialog must be at file top
- component settings modifications are applied via `OverrideUtils`
- the dialog must render correctly regardless of which plugin is active
- component drag functions run frequently — they must be performant (no allocations, no string concat)
- the apply action must update both live frames and edit mode previews in one pass via `ApplySettings`
- snap constants are centralized in `SnapEngine.lua` — never define `SNAP_SIZE` or `EDGE_THRESHOLD` locally

