PDFJS: error on Text rendering for the PDF

问题

Recently the PDF rendering get a messed up text layer where text gets duplicated with the grey colored overlay. No idea about how to fix it as when i remove textLayerFactory: new pdfjsViewer.DefaultTextLayerFactory() it works fine. but need this as if not is render as images which takes a lot of time for large documents

Im using pdfjsViewer.PDFPageView

my code as follows

 getPdf() {

    var pdfDocument;

    if ( this._state !== 'inDOM' ) return false;

    pdfjsLib.disableRange = true;
    pdfjsLib.disableStream = true;

    let self = this;
    pdfDocument = pdfjsLib.getDocument(this.src);
    pdfDocument.promise.then(function(pdf) {
      self.set( 'pdfDocument', pdf );
      self.set( 'maxNumPages',  pdf.numPages );
      self.set( 'prevBtnDisabled', true );
      self.set( 'documentRendered', true );

      self.setViewportWidth();
      self.renderPdf();
    });

    return pdfDocument;
  },

  renderPdf() {

    var pdf = this.pdfDocument,
        maxNumPages,
        pagePromise;

    if ( !pdf ) return false;

    maxNumPages  = this.maxNumPages;

    pagePromise = this.getAndRenderPage( pdf, 1 );

    Array.apply( null, new Array( maxNumPages - 1 ) ).forEach( ( value, index ) => {

      pagePromise = pagePromise.then( () => this.getAndRenderPage( pdf, index + 2 ) );
    } );
  },

  getAndRenderPage( pdf, index ) {

    return pdf.getPage( index ).then( page => this.renderPage( page, index ) );
  },


  renderPage( pdfPage, pageNum ) {

    var parentWidth       = this.$().parent().width(),
        pageViewportScale = ( parentWidth >= this.get( 'breakpoints.mobile' ) ) ? 1.5 : 1.3,
        viewport          = pdfPage.getViewport( { scale: parentWidth / pdfPage.getViewport( { scale: pageViewportScale } ).width } ),
        container         = this.$().find( '.pdf_viewer--container' )[ 0 ],
        pdfPageView;

    pdfPageView = new pdfjsViewer.PDFPageView( {
      container: container,
      id: pageNum,
      scale: viewport.scale,
      defaultViewport: viewport,
     textLayerFactory: new pdfjsViewer.DefaultTextLayerFactory()

    } );
    var pages = this.get('pages');
    // Associates the actual page with the view, and drawing it
     pages.push( pdfPageView );
    this.set( 'pages', pages );
    this.set( 'scale', viewport.scale );z

    pdfPageView.setPdfPage( pdfPage );

    return pdfPageView.draw();
  },

i have seen same kind of questioned asked and its for angular Im importing his image as for the reference in here to give a more explanation about the issue

Reported Issue PDFJS: Text layer rendering twice

回答1:

in the new PDFjs, the CSS file needs to be added seperately from the node_modules folder. therefore i added this as

  app.import( 'node_modules/pdfjs-dist/web/pdf_viewer.css' );

and you can add this as a html import as well.

<link rel="stylesheet" href="../../node_modules/pdfjs-dist/web/pdf_viewer.css">

more information about the example from PDFjs https://github.com/mozilla/pdf.js/blob/master/examples/components/pageviewer.html

来源：https://stackoverflow.com/questions/59151218/pdfjs-error-on-text-rendering-for-the-pdf