新增播放速率调整功能

src/common/utils/lyric-font-player/line-player.js

@@ -38,7 +38,7 @@ const parseExtendedLyric = (lrcLinesMap, extendedLyric) => {
 }
 
 module.exports = class LinePlayer {
-  constructor({ offset = 0, onPlay = function() { }, onSetLyric = function() { } } = {}) {
+  constructor({ offset = 0, rate = 1, onPlay = function() { }, onSetLyric = function() { } } = {}) {
     this.tags = {}
     this.lines = null
     this.onPlay = onPlay
@@ -49,6 +49,7 @@ module.exports = class LinePlayer {
     this.offset = offset
     this._performanceTime = 0
     this._startTime = 0
+    this._rate = rate
   }
 
   _init() {
@@ -119,7 +120,7 @@ module.exports = class LinePlayer {
   }
 
   _currentTime() {
-    return getNow() - this._performanceTime + this._startTime
+    return (getNow() - this._performanceTime) * this._rate + this._startTime
   }
 
   _findCurLineNum(curTime, startIndex = 0) {
@@ -146,14 +147,14 @@ module.exports = class LinePlayer {
 
     if (driftTime >= 0 || this.curLineNum === 0) {
       let nextLine = this.lines[this.curLineNum + 1]
-      this.delay = nextLine.time - curLine.time - driftTime
+      const delay = (nextLine.time - curLine.time - driftTime) / this._rate
 
-      if (this.delay > 0) {
+      if (delay > 0) {
         if (this.isPlay) {
           timeoutTools.start(() => {
             if (!this.isPlay) return
             this._refresh()
-          }, this.delay)
+          }, delay)
         }
         this.onPlay(this.curLineNum, curLine.text, currentTime)
         return
@@ -195,6 +196,13 @@ module.exports = class LinePlayer {
     }
   }
 
+  setPlaybackRate(rate) {
+    this._rate = rate
+    if (!this.lines.length) return
+    if (!this.isPlay) return
+    this.play(this._currentTime())
+  }
+
   setLyric(lyric, extendedLyrics) {
     // console.log(extendedLyrics)
     if (this.isPlay) this.pause()