refactor(ambilight): [PKG-AMBILIGHT-03] split typed lifecycle and recover native canvas sampling

packages/artplayer-plugin-ambilight/src/sampler.ts

@@ -0,0 +1,80 @@
+export function createColorSampler(canvas: HTMLCanvasElement, video: HTMLVideoElement, createCanvas: () => HTMLCanvasElement) {
+  let context: CanvasRenderingContext2D | null
+  try {
+    context = canvas.getContext('2d')
+    canvas.width = 3
+    canvas.height = 3
+  }
+  catch (error) {
+    canvas.width = 0
+    canvas.height = 0
+    throw error
+  }
+  let destroyed = false
+  let replaceCanvas = false
+
+  function read(active: () => boolean): string[] | null {
+    if (destroyed || !active())
+      return null
+    const width = video.videoWidth
+    const height = video.videoHeight
+    if (!Number.isFinite(width) || !Number.isFinite(height) || width <= 0 || height <= 0)
+      return null
+    const w = width / 3
+    const h = height / 3
+    const colors: string[] = []
+    try {
+      if (replaceCanvas) {
+        const replacement = createCanvas()
+        if (destroyed || !active()) {
+          replacement.width = 0
+          replacement.height = 0
+          return null
+        }
+        canvas = replacement
+        context = null
+        context = canvas.getContext('2d')
+        if (destroyed || !active()) {
+          canvas.width = 0
+          canvas.height = 0
+          return null
+        }
+        canvas.width = 3
+        canvas.height = 3
+        replaceCanvas = false
+      }
+      if (!context)
+        return null
+      for (let row = 0; row < 3; row++) {
+        for (let column = 0; column < 3; column++) {
+          if (destroyed || !active())
+            return null
+          context.drawImage(video, column * w, row * h, w, h, 0, 0, 1, 1)
+          if (destroyed || !active())
+            return null
+          const [r, g, b] = context.getImageData(0, 0, 1, 1).data
+          colors.push(`rgb(${r}, ${g}, ${b})`)
+        }
+      }
+      return colors
+    }
+    catch {
+      // Firefox can retain taint after a size reset; replace on the next eligible sample.
+      if (!destroyed) {
+        replaceCanvas = true
+        canvas.width = 0
+        canvas.height = 0
+      }
+      return null
+    }
+  }
+
+  function destroy() {
+    if (destroyed)
+      return
+    destroyed = true
+    canvas.width = 0
+    canvas.height = 0
+  }
+  return { read, destroy }
+}