vue3 quasar 读取pdf到页面上，可拖动缩放

你可以使用Quasar框架和一些现有的JavaScript库来实现在Vue 3中读取PDF并在页面上进行拖动和缩放的功能。以下是一种可能的实现方法：

1. 首先，安装Quasar框架和pdf.js库：

npm install quasar
npm install pdfjs-dist

2. 在Vue组件中引入pdf.js和Quasar的相关组件：

import { QPageContainer, QCard, QCardSection, QScrollArea } from 'quasar'
import pdfjs from 'pdfjs-dist'

export default {
  components: {
    QPageContainer,
    QCard,
    QCardSection,
    QScrollArea
  },
  // ...
}

3. 在Vue组件的模板中，使用QScrollArea组件来创建一个可滚动的区域，并在其中渲染PDF页面：

<template>
  <q-page-container>
    <q-card>
      <q-card-section>
        <q-scroll-area style="height: 500px;">
          <canvas ref="pdfCanvas"></canvas>
        </q-scroll-area>
      </q-card-section>
    </q-card>
  </q-page-container>
</template>

4. 在Vue组件的JavaScript部分，使用pdf.js来加载和渲染PDF页面，并为canvas元素添加拖动和缩放的功能：

export default {
  // ...
  mounted() {
    const canvas = this.$refs.pdfCanvas
    const context = canvas.getContext('2d')

    pdfjs.getDocument('path/to/your/pdf/file.pdf').promise.then((pdf) => {
      pdf.getPage(1).then((page) => {
        const viewport = page.getViewport({ scale: 1.5 })
        canvas.width = viewport.width
        canvas.height = viewport.height

        page.render({
          canvasContext: context,
          viewport: viewport
        })
      })
    })

    let isDragging = false
    let lastX = 0
    let lastY = 0

    canvas.addEventListener('mousedown', (event) => {
      isDragging = true
      lastX = event.clientX
      lastY = event.clientY
    })

    canvas.addEventListener('mousemove', (event) => {
      if (!isDragging) return

      const deltaX = event.clientX - lastX
      const deltaY = event.clientY - lastY

      canvas.scrollLeft += deltaX
      canvas.scrollTop += deltaY

      lastX = event.clientX
      lastY = event.clientY
    })

    canvas.addEventListener('mouseup', () => {
      isDragging = false
    })

    canvas.addEventListener('wheel', (event) => {
      event.preventDefault()

      const delta = event.deltaY

      let scale = 1.1
      if (delta < 0) {
        scale = 1 / scale
      }

      const mouseX = event.clientX - canvas.offsetLeft
      const mouseY = event.clientY - canvas.offsetTop

      const newWidth = canvas.width * scale
      const newHeight = canvas.height * scale

      const scrollLeft = canvas.scrollLeft
      const scrollTop = canvas.scrollTop

      const x = (mouseX + scrollLeft) * scale - mouseX
      const y = (mouseY + scrollTop) * scale - mouseY

      canvas.width = newWidth
      canvas.height = newHeight

      context.scale(scale, scale)
      context.translate(x, y)

      page.render({
        canvasContext: context,
        viewport: page.getViewport({ scale: 1.5 })
      })
    })
  }
}

这样，你就可以在Vue 3中使用Quasar框架和pdf.js库来实现读取PDF并在页面上进行拖动和缩放的功能了。记得将`path/to/your/pdf/file.pdf`替换为你实际的PDF文件路径。