overleaf/services/web/frontend/js/features/pdf-preview/util/pdf-js-wrapper.js

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JavaScript
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// NOTE: using "legacy" build as main build requires webpack v5
// import PDFJS from 'pdfjs-dist/webpack'
import * as PDFJS from 'pdfjs-dist/legacy/build/pdf'
import * as PDFJSViewer from 'pdfjs-dist/legacy/web/pdf_viewer'
import PDFJSWorker from 'pdfjs-dist/legacy/build/pdf.worker'
import 'pdfjs-dist/legacy/web/pdf_viewer.css'
import getMeta from '../../../utils/meta'
if (typeof window !== 'undefined' && 'Worker' in window) {
PDFJS.GlobalWorkerOptions.workerPort = new PDFJSWorker()
}
const params = new URLSearchParams(window.location.search)
const disableFontFace = params.get('disable-font-face') === 'true'
const cMapUrl = getMeta('ol-pdfCMapsPath')
const imageResourcesPath = getMeta('ol-pdfImageResourcesPath')
const rangeChunkSize = 128 * 1024 // 128K chunks
export default class PDFJSWrapper {
constructor(container) {
this.container = container
// create the event bus
const eventBus = new PDFJSViewer.EventBus()
// create the link service
const linkService = new PDFJSViewer.PDFLinkService({
eventBus,
externalLinkTarget: 2,
externalLinkRel: 'noopener',
})
// create the localization
// const l10n = new PDFJSViewer.GenericL10n('en-GB') // TODO: locale mapping?
// create the viewer
const viewer = new PDFJSViewer.PDFViewer({
container,
eventBus,
imageResourcesPath,
linkService,
// l10n, // commented out since it currently breaks `aria-label` rendering in pdf pages
enableScripting: false, // default is false, but set explicitly to be sure
renderInteractiveForms: false,
})
linkService.setViewer(viewer)
this.eventBus = eventBus
this.linkService = linkService
this.viewer = viewer
}
// load a document from a URL
loadDocument(url) {
// prevents any previous loading task from populating the viewer
this.loadDocumentTask = undefined
return new Promise((resolve, reject) => {
this.loadDocumentTask = PDFJS.getDocument({
url,
cMapUrl,
cMapPacked: true,
disableFontFace,
rangeChunkSize,
disableAutoFetch: true,
disableStream: true,
textLayerMode: 2, // PDFJSViewer.TextLayerMode.ENABLE,
})
this.loadDocumentTask.promise
.then(doc => {
if (!this.loadDocumentTask) {
return // ignoring the response since loading task has been aborted
}
const previousDoc = this.viewer.pdfDocument
this.viewer.setDocument(doc)
this.linkService.setDocument(doc)
resolve(doc)
if (previousDoc) {
previousDoc.cleanup().catch(console.error)
previousDoc.destroy()
}
})
.catch(error => {
if (this.loadDocumentTask) {
reject(error)
}
})
.finally(() => {
this.loadDocumentTask = undefined
})
})
}
// update the current scale value if the container size changes
updateOnResize() {
const currentScaleValue = this.viewer.currentScaleValue
if (
currentScaleValue === 'auto' ||
currentScaleValue === 'page-fit' ||
currentScaleValue === 'page-width'
) {
this.viewer.currentScaleValue = currentScaleValue
}
this.viewer.update()
}
// get the page and offset of a click event
clickPosition(event, pageElement, textLayer) {
const { viewport } = this.viewer.getPageView(textLayer.pageNumber - 1)
const pageRect = pageElement.querySelector('canvas').getBoundingClientRect()
const dx = event.clientX - pageRect.left
const dy = event.clientY - pageRect.top
const [left, top] = viewport.convertToPdfPoint(dx, dy)
return {
page: textLayer.pageNumber - 1,
offset: {
left,
top: viewport.viewBox[3] - top,
},
}
}
// get the current page, offset and page size
get currentPosition() {
const pageIndex = this.viewer.currentPageNumber - 1
const pageView = this.viewer.getPageView(pageIndex)
const pageRect = pageView.div.getBoundingClientRect()
const containerRect = this.container.getBoundingClientRect()
const dy = containerRect.top - pageRect.top
const [, , width, height] = pageView.viewport.viewBox
const [, top] = pageView.viewport.convertToPdfPoint(0, dy)
return {
page: pageIndex,
offset: { top, left: 0 },
pageSize: { height, width },
}
}
abortDocumentLoading() {
this.loadDocumentTask = undefined
}
destroy() {
if (this.loadDocumentTask) {
this.loadDocumentTask.destroy()
this.loadDocumentTask = undefined
}
this.viewer.destroy()
}
}