test(jassub): [PKG-JASSUB-09] isolate Firefox bitmap readback stalls

playwright.jassub-diagnostic.config.js

@@ -0,0 +1,14 @@
+import base from './playwright.config.js'
+
+// Diagnostic profile only; canonical browser acceptance uses playwright.config.js.
+export default {
+  ...base,
+  testMatch: /jassub-(?:native|hybrid|platform)\.spec\.js$/,
+  projects: base.projects.filter(project => project.name === 'firefox').map(project => ({
+    ...project,
+    use: {
+      ...project.use,
+      launchOptions: { firefoxUserPrefs: { 'gfx.webrender.software': true } },
+    },
+  })),
+}

refactor/changes/2026-09-14-PKG-JASSUB-09-firefox-diagnostics.md

@@ -0,0 +1,72 @@
+# PKG-JASSUB-09 Firefox 绘制诊断检查点
+
+任务保持 doing。本轮未修改生产源码、默认选项、公开类型或发布产物；没有把一次
+对照通过当作修复。接续 HEAD `7f185f698dbd303b00ca7bc0c21f51cf65c69a04` 的 hybrid
+修复检查点，调查 JASSUB-FIREFOX-OFFSCREEN-01。
+
+## 新证据
+
+默认 Firefox 155.0、Windows、单 worker、不并行运行安装/构建。以前的失败仍保留。
+
+| 对照 | 结果 | 可以支持的结论 |
+| --- | --- | --- |
+| JASSUB 读取前等待 rAF，前置字幕切换 | 1 通过 / 3 失败 | 单等一帧不是修复 |
+| JASSUB 请求软件 WebRender，前置字幕切换 | 4 通过 | 仅该次诊断成功，不能确定硬件原因 |
+| JASSUB 显式 asyncRender=false，前置字幕切换 | 4 通过 | 同步路径可作为异步绘制的对照，不改变消费者默认值 |
+| 原生 Worker fillRect，前置字幕切换 | 4 通过 | 简单绘制对照成功 |
+| 原生 Worker ImageBitmap，初版较小 native 尺寸 | 2 通过 / 2 失败 | 两个核心宿主失败，native 通过；初版报告误写未使用 ImageBitmap，已在测试及此处更正 |
+| ImageBitmap，统一 viewport 尺寸且 native 不加载核心脚本，前置字幕切换 | 2 通过 / 2 失败 | 字幕切换与 candidate 控制失败，published/native 控制通过 |
+| 同样控制，请求软件 WebRender | 3 通过 / 1 失败 | 软件选项也不保证消除问题 |
+| ImageBitmap，等待 Worker 全部完成再读像素，无前置字幕切换 | 3 通过 | 受控无重叠读取路径通过 |
+| 同一最终控制取消读取等待，无前置字幕切换 | 2 通过 / 1 失败 | candidate seek 后仍可失败，前置字幕切换并非必要条件 |
+| 最终 fillRect 控制，三种浏览器，无前置字幕切换 | 9 通过 | Chromium/Firefox 验证 Worker；WebKit 无 transfer，只验证主线程能力回退 |
+
+统一尺寸的失败记录中，Worker `bitmap-start` 时间为 500 ms，`bitmap-ready`
+为 10510 ms，随后立即 `drawn`。这把一次约十秒停顿定位到原生
+createImageBitmap Promise 的等待区间。该页面没有加载 JASSUB wrapper、WASM
+或字体，不能把停顿归因于本次 hybrid guard。另一方面，纯原生页面迄今通过，
+因此尚不能断言彻底排除了核心宿主、样式或合成调度的影响。
+
+读取与绘制重叠是下一步的具体假设，尚未证明因果。需要验证不复制转移画布的
+真实显示证据，例如浏览器截图中的字幕像素，同时保留原失败用例。不能简单删除
+像素断言、扩展超时、全局关闭 offscreen/asyncRender，或更改默认 Firefox 配置。
+修改后的检查必须仍证明播放、seek、布局后的真实字幕，而不只是 Worker 发回通知。
+
+## 可维护的测试入口
+
+`test/browser/jassub-native.spec.js` 保留原默认行为，增加显式 rAF 读取和同步绘制
+诊断参数，并在报告内记录选择。`jassub-platform.spec.js` 只负责分离视频、
+ImageBitmap、转移画布与宿主影响，不承担 ASS 渲染正确性。它使用原生 Worker，
+记录创建/绘制时点，释放 Worker、URL、帧回调和宿主；失败收尾读取已保存的像素
+及当前计数，不再次触发可能阻塞的画布复制。
+
+`playwright.jassub-diagnostic.config.js` 单独请求软件 WebRender。早期运行使用
+同偏好的 cache 配置，原文件和指纹保存在验证记录中；正式文件的 reporter 路径
+继承根配置。这里只确认设置了偏好，没有从 about:support 验证实际 GPU 后端。
+
+在固定 Node 24.21.0 / Yarn Classic 1.22.22 下复跑：
+
+```powershell
+$env:ARTPLAYER_JASSUB_ARTIFACT = 'packages/artplayer-plugin-jassub/dist/artplayer-plugin-jassub.js'
+$env:ARTPLAYER_JASSUB_OFFSCREEN = 'default'
+yarn test:browser test/browser/jassub-hybrid.spec.js test/browser/jassub-native.spec.js --project=firefox --workers=1
+$env:ARTPLAYER_JASSUB_CONTROL_BITMAP = 'true'
+$env:ARTPLAYER_JASSUB_CONTROL_IDLE_READBACK = 'false'
+yarn test:browser test/browser/jassub-platform.spec.js --project=firefox --workers=1
+$env:ARTPLAYER_JASSUB_CONTROL_IDLE_READBACK = 'true'
+yarn test:browser test/browser/jassub-platform.spec.js --project=firefox --workers=1
+```
+
+各命令之间先归档共享 report/results。使用软件对照时指定
+`--config playwright.jassub-diagnostic.config.js`；不要混入默认验收统计。
+关闭诊断时清除对应环境变量。完整路径、报告哈希、选择的参数与失败附件摘要见
+[机器记录](../baselines/jassub-firefox-diagnostics.json)。原始 trace、截图和报告
+保留在 `.cache/`；提交的机器记录用于缓存清理后的证据摘要和复跑定位，不代替原始 trace。
+
+本检查点不关闭 09/05，也不计入 npm、设备、完整组合或三轮发布复盘通过。
+回退本诊断提交只移除测试入口及记录，不改变上一提交的生产实现。
+
+最终只读 ESLint（两个 spec 和诊断配置）、固定 Yarn 严格工具链检查、计划与风险
+登记校验、git diff --check 通过。正式软件配置 `--list` 发现 Firefox 三文件七项；
+此命令仅验证发现/配置，不声称重新运行其播放。没有依赖/锁文件变更，因此没有
+重新安装或重跑全部生产单测/类型打包。上一个生产提交的验证仍只代表其既定范围。

refactor/progress.md

@@ -1,5 +1,19 @@
 # 进度与证据
 
+## PKG-JASSUB-09 Firefox 原生绘制诊断（doing）
+
+新增不加载 JASSUB 的 Worker/ImageBitmap 控制，按新核心、已发布核心及无脚本的
+原生页面验证 seek/viewport 布局。一次失败的 createImageBitmap 等待区间约十秒；
+统一尺寸后纯原生仍通过，尚不能完全排除核心宿主/样式/合成调度影响。前置切字幕
+已不是必要条件：无前置测试的重叠读取 2 通过/1 失败，等待 Worker 完成再读取
+三项通过。软件渲染对照也有失败，rAF 等待亦未解决，均不作为默认配置替代。
+最终 fillRect 三浏览器控制九项通过；这是原生控制，不是 JASSUB 字幕验收。
+本轮只改测试和诊断文档，生产代码/类型/产物未变，保留 09/05 和风险 open。
+[诊断记录](changes/2026-09-14-PKG-JASSUB-09-firefox-diagnostics.md)及
+[机器证据](baselines/jassub-firefox-diagnostics.json)保存不同参数和所有红绿结果。
+下一步验证画布像素复制与异步绘制竞争的假设，补充无需复制转移画布的实际显示
+证据；仍须证明字幕在播放、seek、布局后真实可见，不能只检查 Worker 通知。
+
 ## PKG-JASSUB-09 hybrid 归属修复检查点（doing）
 
 修复旧混合帧干扰新 offscreen 画布、被丢弃完成通知导致等待卡死，以及销毁后

refactor/risk-table.md

@@ -251,4 +251,4 @@
 | JASSUB-QUERY-01 | resolved / 已复现 | Subtitle query errors throw before calling the consumer and leave request listeners attached | PKG-JASSUB-07, PKG-JASSUB-05 |
 | JASSUB-OFFSCREEN-01 | resolved / 已复现 | Default offscreen initialization lets queued resize render before Worker canvas ownership, raising clearRect on false context | PKG-JASSUB-08, PKG-JASSUB-05 |
 | JASSUB-HYBRID-01 | open / 已复现 | Late hybrid frames mutate the new offscreen canvas or throw; terminal track calls recreate transferred canvases | PKG-JASSUB-09, PKG-JASSUB-05 |
-| JASSUB-FIREFOX-OFFSCREEN-01 | open / 已复现 | Windows Firefox default offscreen readback/playback can stall after a preceding subtitle-switch test and web fullscreen | PKG-JASSUB-09, PKG-JASSUB-05 |
+| JASSUB-FIREFOX-OFFSCREEN-01 | open / 已复现 | Windows Firefox offscreen readback and asynchronous ImageBitmap creation can stall through seek/layout, including a minimal Worker control | PKG-JASSUB-09, PKG-JASSUB-05 |

refactor/risks.json

@@ -5640,7 +5640,7 @@
     },
     {
       "id": "JASSUB-FIREFOX-OFFSCREEN-01",
-      "title": "Windows Firefox default offscreen readback/playback can stall after a preceding subtitle-switch test and web fullscreen",
+      "title": "Windows Firefox offscreen readback and asynchronous ImageBitmap creation can stall through seek/layout, including a minimal Worker control",
       "confirmation": "reproduced",
       "status": "open",
       "owners": [
@@ -5650,6 +5650,9 @@
       "evidence": [
         "refactor/changes/2026-09-14-PKG-JASSUB-09-hybrid.md",
         "refactor/baselines/jassub-hybrid-validation.json",
+        "refactor/changes/2026-09-14-PKG-JASSUB-09-firefox-diagnostics.md",
+        "refactor/baselines/jassub-firefox-diagnostics.json",
+        "test/browser/jassub-platform.spec.js",
         "test/browser/jassub-native.spec.js",
         "test/browser/jassub-hybrid.spec.js"
       ],

test/browser/README.md

@@ -185,3 +185,23 @@ cleanup. ARTPLAYER_JASSUB_CUSTOM_CANVAS=true supplies a caller-owned canvas and
 asserts it remains connected after destroy(false). The native report records the
 artifact hash and both mode choices. This does not change the default published
 baseline or establish ESM/offscreen/device acceptance.
+
+JASSUB Firefox diagnostics retain the canonical failing cases. Set
+`ARTPLAYER_JASSUB_OFFSCREEN=default` to exercise native capability selection.
+`ARTPLAYER_JASSUB_ASYNC_RENDER=false` explicitly selects synchronous rendering;
+`ARTPLAYER_JASSUB_READBACK_FRAME=true` waits one animation frame before readback.
+Neither diagnostic changes the default candidate or constitutes a runtime fix.
+`playwright.jassub-diagnostic.config.js` requests Firefox software WebRender for
+comparison only; it is not the canonical browser acceptance configuration.
+
+`jassub-platform.spec.js` isolates native video and a minimal canvas Worker under
+candidate/published cores and a script-free native host. All hosts resize to the
+viewport. Default drawing uses fillRect; `ARTPLAYER_JASSUB_CONTROL_BITMAP=true`
+selects actual createImageBitmap/drawImage/close and records worker stage times.
+`ARTPLAYER_JASSUB_CONTROL_IDLE_READBACK=true` pauses submissions while waiting for
+all draw acknowledgements before copying the display canvas. This is a deliberate
+scheduling diagnostic, not unchanged production timing. Hosts without canvas
+transfer use main-thread fillRect and do not verify the Worker/ImageBitmap path.
+The report records these distinctions and never infers a JASSUB fix from a control
+pass. Preserve each raw report/results directory before the next browser command.
+See [the isolation record](../../refactor/changes/2026-09-14-PKG-JASSUB-09-firefox-diagnostics.md).

test/browser/jassub-native.spec.js

@@ -12,6 +12,15 @@ const customCanvas = process.env.ARTPLAYER_JASSUB_CUSTOM_CANVAS === 'true'
 const code = artifact ? fs.readFileSync(artifact, 'utf8') : readMember(archive, member).toString()
 const onDemandRender = process.env.ARTPLAYER_JASSUB_ON_DEMAND !== 'false'
 const defaultOffscreen = process.env.ARTPLAYER_JASSUB_OFFSCREEN === 'default'
+const readbackFrame = process.env.ARTPLAYER_JASSUB_READBACK_FRAME === 'true'
+const synchronousRender = process.env.ARTPLAYER_JASSUB_ASYNC_RENDER === 'false'
+async function pixels(page, phase) {
+  return page.evaluate(async ({ phase, readbackFrame }) => {
+    if (readbackFrame)
+      await new Promise(requestAnimationFrame)
+    return window.jassubPixels(phase)
+  }, { phase, readbackFrame })
+}
 const subtitles = `[Script Info]
 ScriptType: v4.00+
 PlayResX: 640
@@ -71,7 +80,7 @@ for (const core of ['candidate', 'published', 'published-5.3.1-beta.1']) {
         }
 
         postMessage(message, ...rest) {
-          this.observation.sent.push({ target: message.target, time: message.time, width: message.width, height: message.height })
+          this.observation.sent.push({ target: message.target, time: message.time, width: message.width, height: message.height, asyncRender: message.asyncRender })
           return super.postMessage(message, ...rest)
         }
 
@@ -87,7 +96,7 @@ for (const core of ['candidate', 'published', 'published-5.3.1-beta.1']) {
       await page.locator('#play').click()
       await expect.poll(() => page.evaluate(() => window.art.currentTime)).toBeGreaterThan(0.1)
       await page.locator('#pause').click()
-      await page.evaluate(async ({ subContent, onDemandRender, customCanvas, defaultOffscreen }) => {
+      await page.evaluate(async ({ subContent, onDemandRender, customCanvas, defaultOffscreen, synchronousRender }) => {
         const register = window.artplayerPluginJassub.default || window.artplayerPluginJassub
         let canvas
         if (customCanvas) {
@@ -106,6 +115,7 @@ for (const core of ['candidate', 'published', 'published-5.3.1-beta.1']) {
           availableFonts: { 'liberation sans': '/assets/jassub/default.woff2' },
           fonts: ['/assets/jassub/default.woff2'],
           ...(defaultOffscreen ? {} : { offscreenRender: false }),
+          ...(synchronousRender ? { asyncRender: false } : {}),
           onDemandRender,
           ...(canvas ? { canvas } : {}),
         }))
@@ -147,12 +157,12 @@ for (const core of ['candidate', 'published', 'published-5.3.1-beta.1']) {
             window.jassubNative.snapshots.push(state)
           return state
         }
-      }, { subContent: subtitles, onDemandRender, customCanvas, defaultOffscreen })
+      }, { subContent: subtitles, onDemandRender, customCanvas, defaultOffscreen, synchronousRender })
       const offscreen = await page.evaluate(() => window.jassubNative.offscreen)
       expect(offscreen.selected).toBe(defaultOffscreen && !customCanvas && offscreen.available)
       await page.locator('#play').click()
-      await expect.poll(() => page.evaluate(() => window.jassubPixels().visible)).toBeGreaterThan(100)
-      const before = await page.evaluate(() => window.jassubPixels('before-seek'))
+      await expect.poll(async () => (await pixels(page)).visible).toBeGreaterThan(100)
+      const before = await pixels(page, 'before-seek')
       expect(before.connected).toBe(true)
       await page.locator('#pause').click()
       await page.evaluate(async () => {
@@ -161,17 +171,17 @@ for (const core of ['candidate', 'published', 'published-5.3.1-beta.1']) {
         await seeked
       })
       await page.locator('#play').click()
-      await expect.poll(() => page.evaluate(() => window.jassubPixels().signature)).not.toBe(before.signature)
-      await expect.poll(() => page.evaluate(() => window.jassubPixels().visible)).toBeGreaterThan(100)
-      const after = await page.evaluate(() => window.jassubPixels('after-seek'))
+      await expect.poll(async () => (await pixels(page)).signature).not.toBe(before.signature)
+      await expect.poll(async () => (await pixels(page)).visible).toBeGreaterThan(100)
+      const after = await pixels(page, 'after-seek')
       expect(after.time).toBeGreaterThanOrEqual(10)
       expect(after.signature).not.toBe(before.signature)
       await page.evaluate(() => {
         window.art.fullscreenWeb = true
       })
-      await expect.poll(() => page.evaluate(() => window.jassubPixels().cssWidth)).toBeGreaterThan(before.cssWidth)
-      await expect.poll(() => page.evaluate(() => window.jassubPixels().visible)).toBeGreaterThan(100)
-      await page.evaluate(() => window.jassubPixels('fullscreen'))
+      await expect.poll(async () => (await pixels(page)).cssWidth).toBeGreaterThan(before.cssWidth)
+      await expect.poll(async () => (await pixels(page)).visible).toBeGreaterThan(100)
+      await pixels(page, 'fullscreen')
       await testInfo.attach('actual-jassub-page', { body: await page.screenshot(), contentType: 'image/png' })
       if (artifact)
         await page.evaluate(() => window.jassub.destroy())
@@ -187,6 +197,8 @@ for (const core of ['candidate', 'published', 'published-5.3.1-beta.1']) {
     }
     finally {
       const state = await page.evaluate(() => window.jassubNative).catch(error => ({ unavailable: error.message }))
+      state.readbackFrame = readbackFrame
+      state.synchronousRender = synchronousRender
       await testInfo.attach('actual-jassub-evidence', { body: JSON.stringify({ core, onDemandRender, customCanvas, defaultOffscreen, source: artifact ? { artifact, sha256: hash(code) } : { version: release.version, integrity: release.integrity, member, sha256: hash(code) }, subtitleSha256: hash(subtitles), resources, external, state, limitation: `Actual worker, WASM and local font; offscreen option ${defaultOffscreen ? 'omitted, actual capability/selection recorded' : 'explicitly false'}. Canvas pixels are read from a separate canvas copying the native display bitmap. No full failure recovery, sustained GPU/memory or physical-device acceptance; candidate adds direct-then-host destruction.` }, null, 2), contentType: 'application/json' })
       if (!page.isClosed()) {
         await page.evaluate(() => {

test/browser/jassub-platform.spec.js

@@ -0,0 +1,162 @@
+import process from 'node:process'
+import { expect, test } from './fixtures.js'
+
+const bitmap = process.env.ARTPLAYER_JASSUB_CONTROL_BITMAP === 'true'
+const idleReadback = process.env.ARTPLAYER_JASSUB_CONTROL_IDLE_READBACK === 'true'
+
+for (const host of ['candidate', 'published', 'native']) {
+  test(`Native canvas and video control through seek/layout without JASSUB: ${host}`, async ({ page }, testInfo) => {
+    if (host === 'native') {
+      await page.route('**/test/native-canvas.html', route => route.fulfill({
+        contentType: 'text/html',
+        body: '<!doctype html><html><head><title>Native canvas control</title></head><body></body></html>',
+      }))
+      await page.goto('/test/native-canvas.html')
+    }
+    else {
+      await page.goto(`/test/player.html?core=${host}`)
+    }
+    await page.evaluate(async ({ host, bitmap, idleReadback }) => {
+      let video
+      if (host === 'native') {
+        video = document.createElement('video')
+        video.src = '/assets/sample/steve-jobs.mp4'
+        video.muted = true
+        video.style.width = '640px'
+        video.style.height = '360px'
+        document.body.append(video)
+      }
+      else {
+        window.createPlayer('/assets/sample/steve-jobs.mp4')
+        video = window.art.video
+      }
+      const canvas = document.createElement('canvas')
+      document.body.append(canvas)
+      const readback = document.createElement('canvas')
+      const probe = window.nativeCanvasProbe = { video, canvas, received: 0, frames: 0, sent: 0, bitmap, idleReadback, reading: false, stages: [], errors: [], pixel: null, offscreen: 'transferControlToOffscreen' in canvas, closed: false }
+      const draw = (ctx, canvas, message) => {
+        if (canvas.width !== message.width)
+          canvas.width = message.width
+        if (canvas.height !== message.height)
+          canvas.height = message.height
+        ctx.clearRect(0, 0, canvas.width, canvas.height)
+        ctx.fillStyle = message.time < 5 ? 'red' : 'blue'
+        ctx.fillRect(0, 0, canvas.width, canvas.height)
+      }
+      if (probe.offscreen) {
+        const source = `let canvas, ctx; const draw = ${draw.toString()}; onmessage = async ({data}) => {
+          if (data.canvas) { canvas = data.canvas; ctx = canvas.getContext('2d'); return; }
+          if (${bitmap}) {
+            const pixels = new Uint8ClampedArray(data.width * data.height * 4);
+            for (let i = 0; i < pixels.length; i += 4) { pixels[i + (data.time < 5 ? 0 : 2)] = 255; pixels[i + 3] = 255; }
+            postMessage({stage: 'bitmap-start', time: data.time, at: performance.now()});
+            const image = await createImageBitmap(new ImageData(pixels, data.width, data.height));
+            postMessage({stage: 'bitmap-ready', time: data.time, at: performance.now()});
+            if (canvas.width !== data.width) canvas.width = data.width;
+            if (canvas.height !== data.height) canvas.height = data.height;
+            ctx.clearRect(0, 0, canvas.width, canvas.height);
+            ctx.drawImage(image, 0, 0); image.close();
+          } else { draw(ctx, canvas, data); }
+          postMessage({stage: 'drawn', time: data.time, at: performance.now()});
+        };`
+        probe.workerUrl = URL.createObjectURL(new Blob([source], { type: 'text/javascript' }))
+        probe.worker = new Worker(probe.workerUrl)
+        const transferred = canvas.transferControlToOffscreen()
+        probe.worker.postMessage({ canvas: transferred }, [transferred])
+        probe.worker.onmessage = ({ data }) => {
+          probe.stages.push(data)
+          if (data.stage === 'drawn')
+            probe.received++
+          if (probe.received === probe.sent)
+            probe.drain?.()
+        }
+        probe.worker.onerror = event => probe.errors.push(event.message)
+        probe.post = message => probe.worker.postMessage(message)
+      }
+      else {
+        const ctx = canvas.getContext('2d')
+        probe.post = (message) => {
+          draw(ctx, canvas, message)
+          probe.received++
+        }
+      }
+      const render = () => {
+        if (probe.closed)
+          return
+        probe.frames++
+        if (!probe.reading) {
+          const rect = video.getBoundingClientRect()
+          probe.post({ width: Math.round(rect.width), height: Math.round(rect.height), time: video.currentTime })
+          probe.sent++
+        }
+        if (video.requestVideoFrameCallback)
+          probe.handle = video.requestVideoFrameCallback(render)
+        else
+          probe.handle = requestAnimationFrame(render)
+      }
+      probe.state = () => ({ pixel: probe.pixel, width: canvas.width, height: canvas.height, time: video.currentTime, frames: probe.frames, sent: probe.sent, received: probe.received, quality: video.getVideoPlaybackQuality?.().totalVideoFrames })
+      probe.sample = async () => {
+        if (idleReadback) {
+          probe.reading = true
+          if (probe.received < probe.sent)
+            await new Promise(resolve => probe.drain = resolve)
+        }
+        readback.width = canvas.width
+        readback.height = canvas.height
+        const ctx = readback.getContext('2d')
+        ctx.drawImage(canvas, 0, 0)
+        probe.pixel = [...ctx.getImageData(0, 0, 1, 1).data]
+        probe.reading = false
+        return probe.state()
+      }
+      await video.play()
+      render()
+    }, { host, bitmap, idleReadback })
+    try {
+      await expect.poll(async () => (await page.evaluate(() => window.nativeCanvasProbe.sample())).pixel).toEqual([255, 0, 0, 255])
+      const before = await page.evaluate(() => window.nativeCanvasProbe.sample())
+      await page.evaluate(async () => {
+        const video = window.nativeCanvasProbe.video
+        video.pause()
+        const seeked = new Promise(resolve => video.addEventListener('seeked', resolve, { once: true }))
+        video.currentTime = 10
+        await seeked
+        await video.play()
+      })
+      await expect.poll(async () => (await page.evaluate(() => window.nativeCanvasProbe.sample())).pixel).toEqual([0, 0, 255, 255])
+      await page.evaluate((host) => {
+        if (host === 'native') {
+          Object.assign(window.nativeCanvasProbe.video.style, { position: 'fixed', inset: '0', width: '100vw', height: '100vh' })
+        }
+        else {
+          window.art.fullscreenWeb = true
+        }
+      }, host)
+      await expect.poll(async () => (await page.evaluate(() => window.nativeCanvasProbe.sample())).width).toBeGreaterThan(before.width)
+      await expect.poll(async () => (await page.evaluate(() => window.nativeCanvasProbe.sample())).time).toBeGreaterThan(10.2)
+      await expect.poll(async () => (await page.evaluate(() => window.nativeCanvasProbe.sample())).pixel).toEqual([0, 0, 255, 255])
+    }
+    finally {
+      const evidence = await page.evaluate(() => {
+        const probe = window.nativeCanvasProbe
+        const state = { offscreen: probe.offscreen, bitmap: probe.bitmap, idleReadback: probe.idleReadback, stages: probe.stages, errors: probe.errors, coreLoaded: typeof window.Artplayer !== 'undefined', ...probe.state() }
+        probe.closed = true
+        if (probe.video.cancelVideoFrameCallback)
+          probe.video.cancelVideoFrameCallback(probe.handle)
+        else
+          cancelAnimationFrame(probe.handle)
+        probe.video.pause()
+        probe.worker?.terminate()
+        if (probe.workerUrl)
+          URL.revokeObjectURL(probe.workerUrl)
+        probe.canvas.remove()
+        if (window.art)
+          window.art.destroy(false)
+        else
+          probe.video.remove()
+        return state
+      })
+      await testInfo.attach('native-canvas-control', { body: JSON.stringify({ host, evidence, limitation: 'Native video/frame callbacks and a minimal Worker painting opaque colors. Bitmap mode uses createImageBitmap/drawImage/close; otherwise fillRect. JASSUB wrapper, WASM and fonts are absent. The native host loads no ArtPlayer scripts. Capability fallback without transfer is main-thread fillRect, not offscreen or ImageBitmap verification.' }), contentType: 'application/json' })
+    }
+  })
+}