refactor(mediabunny): [PKG-MB-05] own video iterators, frame pools and rendering

packages/artplayer-proxy-mediabunny/src/video-poster.ts

@@ -0,0 +1,33 @@
+export default class Poster {
+  private image: HTMLImageElement | null = null
+
+  cancel(): void {
+    if (!this.image)
+      return
+    this.image.onload = null
+    this.image.onerror = null
+    this.image = null
+  }
+
+  draw(source: string, current: () => boolean, draw: (image: HTMLImageElement) => void, failure: (error: unknown) => void): void {
+    this.cancel()
+    const image = new Image()
+    this.image = image
+    image.onload = () => {
+      if (this.image !== image || !current())
+        return
+      this.cancel()
+      try {
+        draw(image)
+      }
+      catch (error) {
+        failure(error)
+      }
+    }
+    image.onerror = () => {
+      if (this.image === image)
+        this.cancel()
+    }
+    image.src = source
+  }
+}