用Epub.js引擎开发阅读器

• 实现功能
• • 使用node.js的npm安装epub.js引擎
  • script标签内的关键js代码

实现功能

   电子书解析渲染，获取文献封面，文献信息，获取阅读进度progress，高亮选中文本进而实现笔记功能。

使用node.js的npm安装epub.js引擎

npm install epubjs --save

script标签内的关键js代码

电子书解析和渲染，高亮文本（另外的dialog组件做笔记），获取文献信息，封面信息，上一页，下一页，更新进度等。

import Epub from 'epubjs'

export default {
  name: 'index',
  data () {
    return {
      drawer: false,
      infoDrawer: false,
      notesDrawer: false,
      direction: 'rtl',
      size: '400px',
      book: {},
      coverUrl: '',
      rendition: {},
      navigation: {},
      bookAvailable: false,
      metadata: {},
      notes: [],
      noteIndex: 0,
      dialogFormVisible: false,
      dialogNotesUpdate: '',
      progress: 0,
      selection: null
    }
  },
  mounted () {
    console.log('query: ', this.$route.query)
    this.showEpub()
  },
  methods: {
    updateProgress () {
      // 获得当前章节的百分比并设置 保留4位小数
      const currentLocation = this.book.rendition.currentLocation()
      this.progress = currentLocation.end.percentage.toFixed(6)
      console.log('updateProgress:', this.progress)
    },
    displayProgress (progress) {
      this.progress = progress
      // 获得cfi地址 // progress的范围: 0-1
      const location = progress > 0 ? this.book.locations.cfiFromPercentage(progress) : 0
      // 根据cfi地址渲染电子书
      this.book.rendition.display(location)
    },
    showNoteDialog (index) {
      this.noteIndex = index
      this.dialogFormVisible = true
      this.dialogNotesUpdate = this.notes[index].note
    },
    updateNotes (noteIndex) {
      this.notes[noteIndex].note = this.dialogNotesUpdate
    },
    addNotes (text) {
      this.$message.success('成功新增一条标记！')
      this.notes.push({'mark': text, 'note': ''})
    },
    confirmDelete (index) {
      this.notes.splice(index, 1)
      this.$message.success('删除成功！')
    },
    // 返回上一页（书架）
    goBack () {
      this.$router.go(-1)
    },
    // 根据链接跳转到指定位置
    jumpTo (href) {
      this.drawer = false
      this.rendition.display(href).then(() => {
        this.updateProgress()
      })
    },
    // 上一页
    prevPage () {
      if (this.rendition) {
        this.rendition.prev().then(() => {
          this.updateProgress()
        })
      }
    },
    // 下一页
    nextPage () {
      if (this.rendition) {
        this.rendition.next().then(() => {
          this.updateProgress()
        })
        // const location = percentage > 0 ? this.locations.cfiFromPercentage(percentage) : 0
        // this.rendition.display(location)
      }
    },
    showEpub () { // 电子书解析渲染
      this.book = new Epub(this.$route.query.bookUrl) // 生成Book对象
      // 获取文献信息
      this.book.loaded.metadata.then(metadata => {
        this.metadata = metadata
      })
      // 获取封面信息
      this.book.loaded.cover.then(cover => {
        this.book.archive.createUrl(cover).then(url => {
          this.coverUrl = url
        })
      })
      // 通过Book.renderTo生成Rendition对象
      this.rendition = this.book.renderTo('read', {
        width: window.innerWidth - 460,
        height: window.innerHeight - 130,
        method: 'default'
      })
      // Illustration of how to get text from a saved cfiRange
      let that = this
      this.rendition.on('selected', function (cfiRange, contents) {
        this.book.getRange(cfiRange).then(function (range) {
          if (range) {
            const text = range.toString()
            that.addNotes(text)
          }
        })
      })
      // Apply a class to selected text
      this.rendition.themes.default({
        '::selection': {
          'background': 'rgba(255,255,0, 0.3)'
        },
        '.epubjs-hl': {
          'fill': 'yellow', 'fill-opacity': '0.3', 'mix-blend-mode': 'multiply'
        }
      })
      // Book对象的钩子函数ready
      this.book.ready.then(() => {
        this.navigation = this.book.navigation
        // 生成Locations对象
        return this.book.locations.generate()
      }).then(result => {
        // 保存locations对象
        this.locations = this.book.locations
        // 根据 progress 渲染电子书    // progress数值（0-1）小数
        this.displayProgress(0.0092)
        // 标记电子书为解析完毕状态
        this.bookAvailable = true
      })
    }
  }
}
</script>