createFilterWorker 配置项

Worker 怎样运行滤镜、哪些浏览器会使用它，见图片滤镜指南。

import {
  canRunInWorker,
  createFilterWorker,
  runFilterPipeline,
} from "fabricjs-document-engine/filters";

function createFilterWorker(options?: FilterWorkerOptions): FilterWorker

Runs Fabric image filters in a Web Worker, with progress, cancel and newest-run-wins.

Name	Type	Default	Description
createWorker	() => Worker	the shipped worker	Makes a worker, for bundlers that need their own worker setup.
worker	boolean	true	`false` runs filters in steps on the main thread instead.
poolSize	number	1	Workers to run at once.
bandRows	number	64	Rows per step for pixel filters.
engine	DocumentEngine	none	Records each finished run as one undo step and drops runs that finish after another document opened.

FilterWorker

Name	Type	Default	Description
apply*	(image: FabricImage, filters?: ImageFilter[], options?: ApplyFilterOptions): Promise<boolean>	—	Applies filters to an image. Resolves `true` when it changed, `false` when a newer run replaced it. Rejects with the signal's reason when aborted.
mode*	"worker" \| "main-thread"	—	`worker` or `main-thread`.
terminate*	(): void	—	Stops the workers. Runs still going resolve `false`.

Name	Type	Default	Description
signal	AbortSignal	none	Cancels the run; the image is left as it was.
onProgress	(done: number) => void	none	Called with the share done, from 0 to 1.

runFilterPipeline 就是 Worker 运行的内容。它也可以在主线程上处理任意 ImageData，用在你自己的工具里。

function runFilterPipeline(filters: readonly PipelineFilter[], state: PipelineState, options?: PipelineOptions): Promise<ImageData | undefined>

Runs filters on ImageData in steps, with progress and cancel.

function canRunInWorker(filters: ReadonlyArray<{
  type?: unknown;
  subFilters?: unknown[];
}>): boolean

True when every filter, inside Composed ones too, can run in a worker.

Name	Type	Default	Description
bandRows	number	64	Rows per step for pixel filters.
onProgress	(done: number) => void	none	Called after each step with the share done.
isCancelled	() => boolean	none	Checked after each step; `true` stops the run.
pause	() => Promise<void>	none	Lets other work run between steps.

PIXEL_FILTERS 和 WORKER_FILTERS 分别列出按行分块运行的滤镜类型，以及 Worker 能运行的所有类型。其他滤镜会让 apply 使用 Fabric 的 applyFilters，不论 createFilterWorker 配置项怎样设置。