feat: 增加字幕相关属性和事件，优化字幕切换逻辑

docs/uncompiled/artplayer-proxy-canvas/index.js

@@ -164,7 +164,6 @@ function artplayerProxyCanvas(callback) {
             ...methods,
             ...prototypes
         ];
-        // 存储 canvas 的原始属性
         const originalCanvasProperties = {};
         [
             "width",
@@ -207,8 +206,6 @@ function artplayerProxyCanvas(callback) {
             }
             try {
                 if (video.readyState >= 2) {
-                    // HAVE_CURRENT_DATA or higher
-                    // 使用 createImageBitmap 进行预处理
                     const bitmap = await createImageBitmap(video);
                     ctx.drawImage(bitmap, 0, 0, canvas.width, canvas.height);
                     bitmap.close();
@@ -234,10 +231,8 @@ function artplayerProxyCanvas(callback) {
                     canvasWidth = containerWidth;
                     canvasHeight = canvasWidth / aspectRatio;
                 }
-                // 设置 canvas 大小为实际显示大小
                 canvas.width = canvasWidth;
                 canvas.height = canvasHeight;
-                // 居中 canvas
                 const paddingLeft = (containerWidth - canvasWidth) / 2;
                 const paddingTop = (containerHeight - canvasHeight) / 2;
                 Object.assign(canvas.style, {
@@ -247,13 +242,10 @@ function artplayerProxyCanvas(callback) {
                 console.error("Error in resize function:", error);
             }
         };
-        // 在视频元数据加载完成后设置 canvas 尺寸并绘制第一帧
         art.on("video:loadedmetadata", async ()=>{
             canvas.width = video.videoWidth;
             canvas.height = video.videoHeight;
-            await sleep(300);
             resize();
-            drawFrame();
         });
         art.on("video:play", ()=>{
             cancelAnimationFrame(animationFrame);
@@ -265,7 +257,6 @@ function artplayerProxyCanvas(callback) {
         art.on("resize", resize);
         const destroy = ()=>{
             cancelAnimationFrame(animationFrame);
-        // 清理其他可能的资源...
         };
         art.on("destroy", destroy);
         if (typeof callback === "function") callback.call(art, video, option.url, art);