解决vue-pdf查看pdf文件及打印乱码的问题

import { PDFLinkService } from 'pdfjs-dist/lib/web/pdf_link_service';

export default function(PDFJS) {

 function isPDFDocumentLoadingTask(obj) {

 return typeof(obj) === 'object' && obj !== null && obj.__PDFDocumentLoadingTask === true;
 }

 function createLoadingTask(src, options) {

 var source;
 if ( typeof(src) === 'string' )
  source = { url: src };
 else if ( src instanceof Uint8Array )
  source = { data: src };
 else if ( typeof(src) === 'object' && src !== null )
  source = Object.assign({}, src);
 else
  throw new TypeError('invalid src type');

 var loadingTask = PDFJS.getDocument(source);
 loadingTask.__PDFDocumentLoadingTask = true; // since PDFDocumentLoadingTask is not public

 if ( options && options.onPassword )
  loadingTask.onPassword = options.onPassword;

 if ( options && options.onProgress )
  loadingTask.onProgress = options.onProgress;

 return loadingTask;
 }


 function PDFJSWrapper(canvasElt, annotationLayerElt, emitEvent) {

 var pdfDoc = null;
 var pdfPage = null;
 var pdfRender = null;
 var canceling = false;

 canvasElt.getContext('2d').save();

 function clearCanvas() {

  canvasElt.getContext('2d').clearRect(0, 0, canvasElt.width, canvasElt.height);
 }

 function clearAnnotations() {

  while ( annotationLayerElt.firstChild )
  annotationLayerElt.removeChild(annotationLayerElt.firstChild);
 }

 this.destroy = function() {

  if ( pdfDoc === null )
  return;
  pdfDoc.destroy();
  pdfDoc = null;
 }

 this.getResolutionScale = function() {

  return canvasElt.offsetWidth / canvasElt.width;
 }

 this.printPage = function(dpi, pageNumberOnly) {

  if ( pdfPage === null )
  return;

  // 1in == 72pt
  // 1in == 96px
  var PRINT_RESOLUTION = dpi === undefined ? 150 : dpi;
  var PRINT_UNITS = PRINT_RESOLUTION / 72.0;
  var CSS_UNITS = 96.0 / 72.0;

  // var iframeElt = document.createElement('iframe');
  var printContainerElement = document.createElement('div');
  printContainerElement.setAttribute('id', 'print-container')

  // function removeIframe() {
  //
  // iframeElt.parentNode.removeChild(iframeElt);
  function removePrintContainer() {
  printContainerElement.parentNode.removeChild(printContainerElement);

  }

  new Promise(function(resolve, reject) {

  // iframeElt.frameBorder = '0';
  // iframeElt.scrolling = 'no';
  // iframeElt.width = '0px;'
  // iframeElt.height = '0px;'
  // iframeElt.style.cssText = 'position: absolute; top: 0; left: 0';
  //
  // iframeElt.onload = function() {
  //
  // resolve(this.contentWindow);
  // }
  //
  // window.document.body.appendChild(iframeElt);
  printContainerElement.frameBorder = '0';
  printContainerElement.scrolling = 'no';
  printContainerElement.width = '0px;'
  printContainerElement.height = '0px;'
  printContainerElement.style.cssText = 'position: absolute; top: 0; left: 0';

  window.document.body.appendChild(printContainerElement);
  resolve(window)
  })
  .then(function(win) {

  win.document.title = '';

  return pdfDoc.getPage(1)
  .then(function(page) {

   var viewport = page.getViewport(1);
   // win.document.head.appendChild(win.document.createElement('style')).textContent =
   printContainerElement.appendChild(win.document.createElement('style')).textContent =
   '@supports ((size:A4) and (size:1pt 1pt)) {' +
    '@page { margin: 1pt; size: ' + ((viewport.width * PRINT_UNITS) / CSS_UNITS) + 'pt ' + ((viewport.height * PRINT_UNITS) / CSS_UNITS) + 'pt; }' +
   '}' +

   '#print-canvas { display: none }' +

   '@media print {' +
    'body { margin: 0 }' +
    'canvas { page-break-before: avoid; page-break-after: always; page-break-inside: avoid }' +
   '#print-canvas { page-break-before: avoid; page-break-after: always; page-break-inside: avoid; display: block }' +
   'body > *:not(#print-container) { display: none; }' +
   '}'+

   '@media screen {' +
    'body { margin: 0 }' +
   // '}'+
   //
   // ''
   '}'
   return win;
  })
  })
  .then(function(win) {

  var allPages = [];

  for ( var pageNumber = 1; pageNumber <= pdfDoc.numPages; ++pageNumber ) {

   if ( pageNumberOnly !== undefined && pageNumberOnly.indexOf(pageNumber) === -1 )
   continue;

   allPages.push(
   pdfDoc.getPage(pageNumber)
   .then(function(page) {

    var viewport = page.getViewport(1);

    // var printCanvasElt = win.document.body.appendChild(win.document.createElement('canvas'));
    var printCanvasElt = printContainerElement.appendChild(win.document.createElement('canvas'));
    printCanvasElt.setAttribute('id', 'print-canvas')

    printCanvasElt.width = (viewport.width * PRINT_UNITS);
    printCanvasElt.height = (viewport.height * PRINT_UNITS);

    return page.render({
    canvasContext: printCanvasElt.getContext('2d'),
    transform: [ // Additional transform, applied just before viewport transform.
     PRINT_UNITS, 0, 0,
     PRINT_UNITS, 0, 0
    ],
    viewport: viewport,
    intent: 'print'
    }).promise;
   })
   );
  }

  Promise.all(allPages)
  .then(function() {

   win.focus(); // Required for IE
   if (win.document.queryCommandSupported('print')) {
   win.document.execCommand('print', false, null);
   } else {
   win.print();
    }
   // removeIframe();
   removePrintContainer();
  })
  .catch(function(err) {

   // removeIframe();
   removePrintContainer();
   emitEvent('error', err);
  })
  })
 }

 this.renderPage = function(rotate) {
  if ( pdfRender !== null ) {

  if ( canceling )
   return;
  canceling = true;
  pdfRender.cancel();
  return;
  }

  if ( pdfPage === null )
  return;

  if ( rotate === undefined )
  rotate = pdfPage.rotate;

  var scale = canvasElt.offsetWidth / pdfPage.getViewport(1).width * (window.devicePixelRatio || 1);
  var viewport = pdfPage.getViewport(scale, rotate);

  emitEvent('page-size', viewport.width, viewport.height);

  canvasElt.width = viewport.width;
  canvasElt.height = viewport.height;

  pdfRender = pdfPage.render({
  canvasContext: canvasElt.getContext('2d'),
  viewport: viewport
  });

  annotationLayerElt.style.visibility = 'hidden';
  clearAnnotations();

  var viewer = {
  scrollPageIntoView: function(params) {
   emitEvent('link-clicked', params.pageNumber)
  },
  };

  var linkService = new PDFLinkService();
  linkService.setDocument(pdfDoc);
  linkService.setViewer(viewer);

  pdfPage.getAnnotations({ intent: 'display' })
  .then(function(annotations) {

  PDFJS.AnnotationLayer.render({
   viewport: viewport.clone({ dontFlip: true }),
   div: annotationLayerElt,
   annotations: annotations,
   page: pdfPage,
   linkService: linkService,
   renderInteractiveForms: false
  });
  });

  pdfRender
  .then(function() {
  annotationLayerElt.style.visibility = '';
  canceling = false;
  pdfRender = null;
  })
  .catch(function(err) {

  pdfRender = null;
  if ( err instanceof PDFJS.RenderingCancelledException ) {

   canceling = false;
   this.renderPage(rotate);
   return;
  }
  emitEvent('error', err);
  }.bind(this))
 }


 this.forEachPage = function(pageCallback) {

  var numPages = pdfDoc.numPages;

  (function next(pageNum) {

  pdfDoc.getPage(pageNum)
  .then(pageCallback)
  .then(function() {

   if ( ++pageNum <= numPages )
   next(pageNum);
  })
  })(1);
 }


 this.loadPage = function(pageNumber, rotate) {

  pdfPage = null;

  if ( pdfDoc === null )
  return;

  pdfDoc.getPage(pageNumber)
  .then(function(page) {

  pdfPage = page;
  this.renderPage(rotate);
  emitEvent('page-loaded', page.pageNumber);
  }.bind(this))
  .catch(function(err) {

  clearCanvas();
  clearAnnotations();
  emitEvent('error', err);
  });
 }

 this.loadDocument = function(src) {

  pdfDoc = null;
  pdfPage = null;

  emitEvent('num-pages', undefined);

  if ( !src ) {

  canvasElt.removeAttribute('width');
  canvasElt.removeAttribute('height');
  clearAnnotations();
  return;
  }

  if ( isPDFDocumentLoadingTask(src) ) {

  if ( src.destroyed ) {

   emitEvent('error', new Error('loadingTask has been destroyed'));
   return
  }

  var loadingTask = src;
  } else {

  var loadingTask = createLoadingTask(src, {
   onPassword: function(updatePassword, reason) {

   var reasonStr;
   switch (reason) {
    case PDFJS.PasswordResponses.NEED_PASSWORD:
    reasonStr = 'NEED_PASSWORD';
    break;
    case PDFJS.PasswordResponses.INCORRECT_PASSWORD:
    reasonStr = 'INCORRECT_PASSWORD';
    break;
   }
   emitEvent('password', updatePassword, reasonStr);
   },
   onProgress: function(status) {

   var ratio = status.loaded / status.total;
   emitEvent('progress', Math.min(ratio, 1));
   }
  });
  }

  loadingTask
  .then(function(pdf) {

  pdfDoc = pdf;
  emitEvent('num-pages', pdf.numPages);
  emitEvent('loaded');
  })
  .catch(function(err) {

  clearCanvas();
  clearAnnotations();
  emitEvent('error', err);
  })
 }

 annotationLayerElt.style.transformOrigin = '0 0';
 }

 return {
 createLoadingTask: createLoadingTask,
 PDFJSWrapper: PDFJSWrapper,
 }
}

***
PDFJS.cMapUrl = '../../static/cmaps/';
PDFJS.cMapPacked = true;
***
PDFJS.cMapUrl = '../../static/cmaps/';//这里面是相对路径