fix(弹幕组件): 增强弹幕宽度测量逻辑和默认值处理

改进弹幕宽度测量功能，增加重试机制和更保守的默认值计算
优化动画启动时机，确保宽度测量完成后再开始

@@ -105,9 +105,16 @@ const WINDOW_WIDTH = SYSTEM_INFO.windowWidth
 
 // px 转 rpx
 const toRpx = (px) => (px * CONTAINER_WIDTH) / WINDOW_WIDTH
-// 获取弹幕宽度（rpx）
+// 获取弹幕宽度 - 增强版，提供更安全的默认值
 const getDanmuWidth = (danmu) => {
-  return danmu?.widthRpx && danmu.widthRpx > 0 ? danmu.widthRpx : DANMU_WIDTH
+  if (danmu.widthRpx && danmu.widthRpx > 0) {
+    return danmu.widthRpx
+  }
+  // 如果没有测量到宽度，使用更保守的默认值
+  // 根据内容长度动态估算，避免过短导致重叠
+  const contentLength = danmu.data?.familyName?.length || 0
+  const estimatedWidth = Math.max(DANMU_WIDTH, contentLength * 30 + 100) // 每字符约30rpx + 100rpx边距
+  return Math.min(estimatedWidth, DANMU_WIDTH * 2) // 最大不超过2倍默认宽度
 }
 // 重新计算时长，保证速度一致
 const recalculateDuration = (danmu) => {
@@ -115,18 +122,37 @@ const recalculateDuration = (danmu) => {
   const totalDistance = CONTAINER_WIDTH + width + EXTRA_DISTANCE
   danmu.duration = (totalDistance / (props.danmuSpeed * 0.6)) * 1000
 }
-// 测量弹幕真实宽度（px），存为 rpx
-const measureDanmuWidth = (danmu) => new Promise((resolve) => {
+// 测量弹幕真实宽度（px），存为 rpx - 增强版，支持重试和更保守的默认值
+const measureDanmuWidth = (danmu, retryCount = 0) => new Promise((resolve) => {
+  const maxRetries = 3
+  const retryDelay = 50 // 50ms 重试间隔
+  
   try {
     const selector = `#danmu-${danmu.id} .danmu-content`
     Taro.createSelectorQuery().select(selector).boundingClientRect(rect => {
-      if (rect && rect.width) {
+      if (rect && rect.width && rect.width > 0) {
         danmu.widthRpx = toRpx(rect.width)
+        resolve(getDanmuWidth(danmu))
+      } else if (retryCount < maxRetries) {
+        // 测量失败，延迟重试
+        setTimeout(() => {
+          measureDanmuWidth(danmu, retryCount + 1).then(resolve)
+        }, retryDelay)
+      } else {
+        // 重试失败，使用更保守的默认宽度（比实际内容更大）
+        danmu.widthRpx = DANMU_WIDTH * 1.5 // 使用1.5倍默认宽度作为安全值
+        resolve(getDanmuWidth(danmu))
       }
-      resolve(getDanmuWidth(danmu))
     }).exec()
   } catch (e) {
-    resolve(getDanmuWidth(danmu))
+    if (retryCount < maxRetries) {
+      setTimeout(() => {
+        measureDanmuWidth(danmu, retryCount + 1).then(resolve)
+      }, retryDelay)
+    } else {
+      danmu.widthRpx = DANMU_WIDTH * 1.5
+      resolve(getDanmuWidth(danmu))
+    }
   }
 })
 
@@ -168,7 +194,7 @@ const getDanmuStyle = (danmu, trackIndex) => {
 
   return {
     transform: `translateX(${danmu.x}rpx)`,
-    transition: danmu.isMoving ? `transform ${(danmu.remainingDuration ?? danmu.duration)}ms linear` : 'none',
+    transition: danmu.isMoving ? 'transform ' + (danmu.remainingDuration ?? danmu.duration) + 'ms linear' : 'none',
     opacity: danmu.opacity || 1,
     // 明确设置垂直位置
     position: 'absolute',
@@ -279,12 +305,17 @@ const addDanmuToTrack = (danmu, targetTrack = null, options = {}) => {
   track.danmus.push(danmu)
   track.lastDanmuTime = Date.now()
 
-  // 启动弹幕动画
+  // 启动弹幕动画 - 确保宽度测量完成后再开始
   nextTick(async () => {
+    // 等待宽度测量完成，确保获得准确宽度
     await measureDanmuWidth(danmu)
     recalculateDuration(danmu)
+    
     // 重置起始时间，保证时长重新计算后动画正确
     danmu.startTime = Date.now()
+    
+    // 再次等待一个 tick，确保 DOM 完全更新
+    await nextTick()
     startDanmuAnimation(danmu, track)
   })