# Classes

Import these from `@grafloria/renderer`.

## Classes

### `CanvasStyleResolver`

Resolves VNode props → concrete paint values, reproducing the SVG cascade. The CLASS-RULE layer is the export card's flattener; this adds priority order,
inheritance and typed parsing on top.

```ts
class CanvasStyleResolver
```

**Properties**

| Name | Type | Default | Description |
| --- | --- | --- | --- |
| `warnings` | `string[]` | `[]` | Declarations dropped because a variable could not be resolved. |

**Methods**

- `constructor(options: StyleResolverOptions)`
- `setTheme(theme: Theme, varOverrides?: Record<string, string>): void`
- `getTheme(): Theme`
- `rootStyle(): ComputedStyle` — The root style every diagram starts from (theme font, no paint inherited).
- `resolve(props: VNodeProps | undefined, inherited: ComputedStyle): ComputedStyle` — Compute an element's style: inherit from the parent, then apply
presentation attributes < matched class rules < inline style.

### `DirtyRegionTracker`

```ts
class DirtyRegionTracker
```

**Methods**

- `invalidateAll(): void` — Next frame repaints everything (camera moved, theme swapped, resized …).
- `reset(): void` — Forget everything (a new diagram, or a disposed renderer).
- `diff(current: Map<string, VNode>, measure: (vnode: VNode) => Bounds | null): DirtyDiff` — Diff this frame's entities against the last one.
- `getBounds(key: string): Bounds | null | undefined` — Bounds recorded for an entity on the last frame (testing / diagnostics).
- `get size(): number`

### `VNodePainter`

Paints VNode trees. Stateless between frames apart from the colour-key
allocator the caller injects.

```ts
class VNodePainter
```

**Methods**

- `constructor(private readonly resolver: CanvasStyleResolver)`
- `paint(ctx: Canvas2DLike, root: VNode, options: PaintOptions): PaintResult`
- `measure(vnode: VNode, worldToDevice: Matrix = IDENTITY): Bounds | null` — World bounds of a subtree, drawing nothing. Used by the dirty tracker to
measure the entities that actually changed (and only those).