pdfjs-dist/lib/web/pdf_viewer.js

/* Copyright 2017 Mozilla Foundation
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
'use strict';

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.PDFViewer = exports.PresentationModeState = undefined;

var _pdfjs = require('./pdfjs');

var _ui_utils = require('./ui_utils');

var _pdf_rendering_queue = require('./pdf_rendering_queue');

var _annotation_layer_builder = require('./annotation_layer_builder');

var _dom_events = require('./dom_events');

var _pdf_page_view = require('./pdf_page_view');

var _pdf_link_service = require('./pdf_link_service');

var _text_layer_builder = require('./text_layer_builder');

var PresentationModeState = {
  UNKNOWN: 0,
  NORMAL: 1,
  CHANGING: 2,
  FULLSCREEN: 3
};
var DEFAULT_CACHE_SIZE = 10;
var PDFViewer = function pdfViewer() {
  function PDFPageViewBuffer(size) {
    var data = [];
    this.push = function cachePush(view) {
      var i = data.indexOf(view);
      if (i >= 0) {
        data.splice(i, 1);
      }
      data.push(view);
      if (data.length > size) {
        data.shift().destroy();
      }
    };
    this.resize = function (newSize) {
      size = newSize;
      while (data.length > size) {
        data.shift().destroy();
      }
    };
  }
  function isSameScale(oldScale, newScale) {
    if (newScale === oldScale) {
      return true;
    }
    if (Math.abs(newScale - oldScale) < 1e-15) {
      return true;
    }
    return false;
  }
  function isPortraitOrientation(size) {
    return size.width <= size.height;
  }
  function PDFViewer(options) {
    this.container = options.container;
    this.viewer = options.viewer || options.container.firstElementChild;
    this.eventBus = options.eventBus || (0, _dom_events.getGlobalEventBus)();
    this.linkService = options.linkService || new _pdf_link_service.SimpleLinkService();
    this.downloadManager = options.downloadManager || null;
    this.removePageBorders = options.removePageBorders || false;
    this.enhanceTextSelection = options.enhanceTextSelection || false;
    this.renderInteractiveForms = options.renderInteractiveForms || false;
    this.enablePrintAutoRotate = options.enablePrintAutoRotate || false;
    this.renderer = options.renderer || _ui_utils.RendererType.CANVAS;
    this.defaultRenderingQueue = !options.renderingQueue;
    if (this.defaultRenderingQueue) {
      this.renderingQueue = new _pdf_rendering_queue.PDFRenderingQueue();
      this.renderingQueue.setViewer(this);
    } else {
      this.renderingQueue = options.renderingQueue;
    }
    this.scroll = (0, _ui_utils.watchScroll)(this.container, this._scrollUpdate.bind(this));
    this.presentationModeState = PresentationModeState.UNKNOWN;
    this._resetView();
    if (this.removePageBorders) {
      this.viewer.classList.add('removePageBorders');
    }
  }
  PDFViewer.prototype = {
    get pagesCount() {
      return this._pages.length;
    },
    getPageView: function getPageView(index) {
      return this._pages[index];
    },

    get pageViewsReady() {
      return this._pageViewsReady;
    },
    get currentPageNumber() {
      return this._currentPageNumber;
    },
    set currentPageNumber(val) {
      if ((val | 0) !== val) {
        throw new Error('Invalid page number.');
      }
      if (!this.pdfDocument) {
        this._currentPageNumber = val;
        return;
      }
      this._setCurrentPageNumber(val, true);
    },
    _setCurrentPageNumber: function PDFViewer_setCurrentPageNumber(val, resetCurrentPageView) {
      if (this._currentPageNumber === val) {
        if (resetCurrentPageView) {
          this._resetCurrentPageView();
        }
        return;
      }
      if (!(0 < val && val <= this.pagesCount)) {
        console.error('PDFViewer_setCurrentPageNumber: "' + val + '" is out of bounds.');
        return;
      }
      var arg = {
        source: this,
        pageNumber: val,
        pageLabel: this._pageLabels && this._pageLabels[val - 1]
      };
      this._currentPageNumber = val;
      this.eventBus.dispatch('pagechanging', arg);
      this.eventBus.dispatch('pagechange', arg);
      if (resetCurrentPageView) {
        this._resetCurrentPageView();
      }
    },
    get currentPageLabel() {
      return this._pageLabels && this._pageLabels[this._currentPageNumber - 1];
    },
    set currentPageLabel(val) {
      var pageNumber = val | 0;
      if (this._pageLabels) {
        var i = this._pageLabels.indexOf(val);
        if (i >= 0) {
          pageNumber = i + 1;
        }
      }
      this.currentPageNumber = pageNumber;
    },
    get currentScale() {
      return this._currentScale !== _ui_utils.UNKNOWN_SCALE ? this._currentScale : _ui_utils.DEFAULT_SCALE;
    },
    set currentScale(val) {
      if (isNaN(val)) {
        throw new Error('Invalid numeric scale');
      }
      if (!this.pdfDocument) {
        this._currentScale = val;
        this._currentScaleValue = val !== _ui_utils.UNKNOWN_SCALE ? val.toString() : null;
        return;
      }
      this._setScale(val, false);
    },
    get currentScaleValue() {
      return this._currentScaleValue;
    },
    set currentScaleValue(val) {
      if (!this.pdfDocument) {
        this._currentScale = isNaN(val) ? _ui_utils.UNKNOWN_SCALE : val;
        this._currentScaleValue = val.toString();
        return;
      }
      this._setScale(val, false);
    },
    get pagesRotation() {
      return this._pagesRotation;
    },
    set pagesRotation(rotation) {
      if (!(typeof rotation === 'number' && rotation % 90 === 0)) {
        throw new Error('Invalid pages rotation angle.');
      }
      this._pagesRotation = rotation;
      if (!this.pdfDocument) {
        return;
      }
      for (var i = 0, l = this._pages.length; i < l; i++) {
        var pageView = this._pages[i];
        pageView.update(pageView.scale, rotation);
      }
      this._setScale(this._currentScaleValue, true);
      if (this.defaultRenderingQueue) {
        this.update();
      }
    },
    setDocument: function setDocument(pdfDocument) {
      var _this = this;

      if (this.pdfDocument) {
        this._cancelRendering();
        this._resetView();
      }
      this.pdfDocument = pdfDocument;
      if (!pdfDocument) {
        return;
      }
      var pagesCount = pdfDocument.numPages;
      var pagesCapability = (0, _pdfjs.createPromiseCapability)();
      this.pagesPromise = pagesCapability.promise;
      pagesCapability.promise.then(function () {
        _this._pageViewsReady = true;
        _this.eventBus.dispatch('pagesloaded', {
          source: _this,
          pagesCount: pagesCount
        });
      });
      var isOnePageRenderedResolved = false;
      var onePageRenderedCapability = (0, _pdfjs.createPromiseCapability)();
      this.onePageRendered = onePageRenderedCapability.promise;
      var bindOnAfterAndBeforeDraw = function bindOnAfterAndBeforeDraw(pageView) {
        pageView.onBeforeDraw = function () {
          _this._buffer.push(pageView);
        };
        pageView.onAfterDraw = function () {
          if (!isOnePageRenderedResolved) {
            isOnePageRenderedResolved = true;
            onePageRenderedCapability.resolve();
          }
        };
      };
      var firstPagePromise = pdfDocument.getPage(1);
      this.firstPagePromise = firstPagePromise;
      return firstPagePromise.then(function (pdfPage) {
        var scale = _this.currentScale;
        var viewport = pdfPage.getViewport(scale * _ui_utils.CSS_UNITS);
        for (var pageNum = 1; pageNum <= pagesCount; ++pageNum) {
          var textLayerFactory = null;
          if (!_pdfjs.PDFJS.disableTextLayer) {
            textLayerFactory = _this;
          }
          var pageView = new _pdf_page_view.PDFPageView({
            container: _this.viewer,
            eventBus: _this.eventBus,
            id: pageNum,
            scale: scale,
            defaultViewport: viewport.clone(),
            renderingQueue: _this.renderingQueue,
            textLayerFactory: textLayerFactory,
            annotationLayerFactory: _this,
            enhanceTextSelection: _this.enhanceTextSelection,
            renderInteractiveForms: _this.renderInteractiveForms,
            renderer: _this.renderer
          });
          bindOnAfterAndBeforeDraw(pageView);
          _this._pages.push(pageView);
        }
        onePageRenderedCapability.promise.then(function () {
          if (_pdfjs.PDFJS.disableAutoFetch) {
            pagesCapability.resolve();
            return;
          }
          var getPagesLeft = pagesCount;
          for (var pageNum = 1; pageNum <= pagesCount; ++pageNum) {
            pdfDocument.getPage(pageNum).then(function (pageNum, pdfPage) {
              var pageView = this._pages[pageNum - 1];
              if (!pageView.pdfPage) {
                pageView.setPdfPage(pdfPage);
              }
              this.linkService.cachePageRef(pageNum, pdfPage.ref);
              if (--getPagesLeft === 0) {
                pagesCapability.resolve();
              }
            }.bind(_this, pageNum));
          }
        });
        _this.eventBus.dispatch('pagesinit', { source: _this });
        if (_this.defaultRenderingQueue) {
          _this.update();
        }
        if (_this.findController) {
          _this.findController.resolveFirstPage();
        }
      });
    },

    setPageLabels: function PDFViewer_setPageLabels(labels) {
      if (!this.pdfDocument) {
        return;
      }
      if (!labels) {
        this._pageLabels = null;
      } else if (!(labels instanceof Array && this.pdfDocument.numPages === labels.length)) {
        this._pageLabels = null;
        console.error('PDFViewer_setPageLabels: Invalid page labels.');
      } else {
        this._pageLabels = labels;
      }
      for (var i = 0, ii = this._pages.length; i < ii; i++) {
        var pageView = this._pages[i];
        var label = this._pageLabels && this._pageLabels[i];
        pageView.setPageLabel(label);
      }
    },
    _resetView: function _resetView() {
      this._pages = [];
      this._currentPageNumber = 1;
      this._currentScale = _ui_utils.UNKNOWN_SCALE;
      this._currentScaleValue = null;
      this._pageLabels = null;
      this._buffer = new PDFPageViewBuffer(DEFAULT_CACHE_SIZE);
      this._location = null;
      this._pagesRotation = 0;
      this._pagesRequests = [];
      this._pageViewsReady = false;
      this.viewer.textContent = '';
    },

    _scrollUpdate: function PDFViewer_scrollUpdate() {
      if (this.pagesCount === 0) {
        return;
      }
      this.update();
      for (var i = 0, ii = this._pages.length; i < ii; i++) {
        this._pages[i].updatePosition();
      }
    },
    _setScaleDispatchEvent: function pdfViewer_setScaleDispatchEvent(newScale, newValue, preset) {
      var arg = {
        source: this,
        scale: newScale,
        presetValue: preset ? newValue : undefined
      };
      this.eventBus.dispatch('scalechanging', arg);
      this.eventBus.dispatch('scalechange', arg);
    },
    _setScaleUpdatePages: function pdfViewer_setScaleUpdatePages(newScale, newValue, noScroll, preset) {
      this._currentScaleValue = newValue.toString();
      if (isSameScale(this._currentScale, newScale)) {
        if (preset) {
          this._setScaleDispatchEvent(newScale, newValue, true);
        }
        return;
      }
      for (var i = 0, ii = this._pages.length; i < ii; i++) {
        this._pages[i].update(newScale);
      }
      this._currentScale = newScale;
      if (!noScroll) {
        var page = this._currentPageNumber,
            dest;
        if (this._location && !_pdfjs.PDFJS.ignoreCurrentPositionOnZoom && !(this.isInPresentationMode || this.isChangingPresentationMode)) {
          page = this._location.pageNumber;
          dest = [null, { name: 'XYZ' }, this._location.left, this._location.top, null];
        }
        this.scrollPageIntoView({
          pageNumber: page,
          destArray: dest,
          allowNegativeOffset: true
        });
      }
      this._setScaleDispatchEvent(newScale, newValue, preset);
      if (this.defaultRenderingQueue) {
        this.update();
      }
    },
    _setScale: function PDFViewer_setScale(value, noScroll) {
      var scale = parseFloat(value);
      if (scale > 0) {
        this._setScaleUpdatePages(scale, value, noScroll, false);
      } else {
        var currentPage = this._pages[this._currentPageNumber - 1];
        if (!currentPage) {
          return;
        }
        var hPadding = this.isInPresentationMode || this.removePageBorders ? 0 : _ui_utils.SCROLLBAR_PADDING;
        var vPadding = this.isInPresentationMode || this.removePageBorders ? 0 : _ui_utils.VERTICAL_PADDING;
        var pageWidthScale = (this.container.clientWidth - hPadding) / currentPage.width * currentPage.scale;
        var pageHeightScale = (this.container.clientHeight - vPadding) / currentPage.height * currentPage.scale;
        switch (value) {
          case 'page-actual':
            scale = 1;
            break;
          case 'page-width':
            scale = pageWidthScale;
            break;
          case 'page-height':
            scale = pageHeightScale;
            break;
          case 'page-fit':
            scale = Math.min(pageWidthScale, pageHeightScale);
            break;
          case 'auto':
            var isLandscape = currentPage.width > currentPage.height;
            var horizontalScale = isLandscape ? Math.min(pageHeightScale, pageWidthScale) : pageWidthScale;
            scale = Math.min(_ui_utils.MAX_AUTO_SCALE, horizontalScale);
            break;
          default:
            console.error('PDFViewer_setScale: "' + value + '" is an unknown zoom value.');
            return;
        }
        this._setScaleUpdatePages(scale, value, noScroll, true);
      }
    },
    _resetCurrentPageView: function _resetCurrentPageView() {
      if (this.isInPresentationMode) {
        this._setScale(this._currentScaleValue, true);
      }
      var pageView = this._pages[this._currentPageNumber - 1];
      (0, _ui_utils.scrollIntoView)(pageView.div);
    },

    scrollPageIntoView: function PDFViewer_scrollPageIntoView(params) {
      if (!this.pdfDocument) {
        return;
      }
      if (arguments.length > 1 || typeof params === 'number') {
        console.warn('Call of scrollPageIntoView() with obsolete signature.');
        var paramObj = {};
        if (typeof params === 'number') {
          paramObj.pageNumber = params;
        }
        if (arguments[1] instanceof Array) {
          paramObj.destArray = arguments[1];
        }
        params = paramObj;
      }
      var pageNumber = params.pageNumber || 0;
      var dest = params.destArray || null;
      var allowNegativeOffset = params.allowNegativeOffset || false;
      if (this.isInPresentationMode || !dest) {
        this._setCurrentPageNumber(pageNumber, true);
        return;
      }
      var pageView = this._pages[pageNumber - 1];
      if (!pageView) {
        console.error('PDFViewer_scrollPageIntoView: ' + 'Invalid "pageNumber" parameter.');
        return;
      }
      var x = 0,
          y = 0;
      var width = 0,
          height = 0,
          widthScale,
          heightScale;
      var changeOrientation = pageView.rotation % 180 === 0 ? false : true;
      var pageWidth = (changeOrientation ? pageView.height : pageView.width) / pageView.scale / _ui_utils.CSS_UNITS;
      var pageHeight = (changeOrientation ? pageView.width : pageView.height) / pageView.scale / _ui_utils.CSS_UNITS;
      var scale = 0;
      switch (dest[1].name) {
        case 'XYZ':
          x = dest[2];
          y = dest[3];
          scale = dest[4];
          x = x !== null ? x : 0;
          y = y !== null ? y : pageHeight;
          break;
        case 'Fit':
        case 'FitB':
          scale = 'page-fit';
          break;
        case 'FitH':
        case 'FitBH':
          y = dest[2];
          scale = 'page-width';
          if (y === null && this._location) {
            x = this._location.left;
            y = this._location.top;
          }
          break;
        case 'FitV':
        case 'FitBV':
          x = dest[2];
          width = pageWidth;
          height = pageHeight;
          scale = 'page-height';
          break;
        case 'FitR':
          x = dest[2];
          y = dest[3];
          width = dest[4] - x;
          height = dest[5] - y;
          var hPadding = this.removePageBorders ? 0 : _ui_utils.SCROLLBAR_PADDING;
          var vPadding = this.removePageBorders ? 0 : _ui_utils.VERTICAL_PADDING;
          widthScale = (this.container.clientWidth - hPadding) / width / _ui_utils.CSS_UNITS;
          heightScale = (this.container.clientHeight - vPadding) / height / _ui_utils.CSS_UNITS;
          scale = Math.min(Math.abs(widthScale), Math.abs(heightScale));
          break;
        default:
          console.error('PDFViewer_scrollPageIntoView: \'' + dest[1].name + '\' is not a valid destination type.');
          return;
      }
      if (scale && scale !== this._currentScale) {
        this.currentScaleValue = scale;
      } else if (this._currentScale === _ui_utils.UNKNOWN_SCALE) {
        this.currentScaleValue = _ui_utils.DEFAULT_SCALE_VALUE;
      }
      if (scale === 'page-fit' && !dest[4]) {
        (0, _ui_utils.scrollIntoView)(pageView.div);
        return;
      }
      var boundingRect = [pageView.viewport.convertToViewportPoint(x, y), pageView.viewport.convertToViewportPoint(x + width, y + height)];
      var left = Math.min(boundingRect[0][0], boundingRect[1][0]);
      var top = Math.min(boundingRect[0][1], boundingRect[1][1]);
      if (!allowNegativeOffset) {
        left = Math.max(left, 0);
        top = Math.max(top, 0);
      }
      (0, _ui_utils.scrollIntoView)(pageView.div, {
        left: left,
        top: top
      });
    },
    _updateLocation: function _updateLocation(firstPage) {
      var currentScale = this._currentScale;
      var currentScaleValue = this._currentScaleValue;
      var normalizedScaleValue = parseFloat(currentScaleValue) === currentScale ? Math.round(currentScale * 10000) / 100 : currentScaleValue;
      var pageNumber = firstPage.id;
      var pdfOpenParams = '#page=' + pageNumber;
      pdfOpenParams += '&zoom=' + normalizedScaleValue;
      var currentPageView = this._pages[pageNumber - 1];
      var container = this.container;
      var topLeft = currentPageView.getPagePoint(container.scrollLeft - firstPage.x, container.scrollTop - firstPage.y);
      var intLeft = Math.round(topLeft[0]);
      var intTop = Math.round(topLeft[1]);
      pdfOpenParams += ',' + intLeft + ',' + intTop;
      this._location = {
        pageNumber: pageNumber,
        scale: normalizedScaleValue,
        top: intTop,
        left: intLeft,
        pdfOpenParams: pdfOpenParams
      };
    },

    update: function PDFViewer_update() {
      var visible = this._getVisiblePages();
      var visiblePages = visible.views;
      if (visiblePages.length === 0) {
        return;
      }
      var suggestedCacheSize = Math.max(DEFAULT_CACHE_SIZE, 2 * visiblePages.length + 1);
      this._buffer.resize(suggestedCacheSize);
      this.renderingQueue.renderHighestPriority(visible);
      var currentId = this._currentPageNumber;
      var firstPage = visible.first;
      for (var i = 0, ii = visiblePages.length, stillFullyVisible = false; i < ii; ++i) {
        var page = visiblePages[i];
        if (page.percent < 100) {
          break;
        }
        if (page.id === currentId) {
          stillFullyVisible = true;
          break;
        }
      }
      if (!stillFullyVisible) {
        currentId = visiblePages[0].id;
      }
      if (!this.isInPresentationMode) {
        this._setCurrentPageNumber(currentId);
      }
      this._updateLocation(firstPage);
      this.eventBus.dispatch('updateviewarea', {
        source: this,
        location: this._location
      });
    },
    containsElement: function containsElement(element) {
      return this.container.contains(element);
    },
    focus: function focus() {
      this.container.focus();
    },

    get isInPresentationMode() {
      return this.presentationModeState === PresentationModeState.FULLSCREEN;
    },
    get isChangingPresentationMode() {
      return this.presentationModeState === PresentationModeState.CHANGING;
    },
    get isHorizontalScrollbarEnabled() {
      return this.isInPresentationMode ? false : this.container.scrollWidth > this.container.clientWidth;
    },
    _getVisiblePages: function _getVisiblePages() {
      if (!this.isInPresentationMode) {
        return (0, _ui_utils.getVisibleElements)(this.container, this._pages, true);
      }
      var visible = [];
      var currentPage = this._pages[this._currentPageNumber - 1];
      visible.push({
        id: currentPage.id,
        view: currentPage
      });
      return {
        first: currentPage,
        last: currentPage,
        views: visible
      };
    },
    cleanup: function cleanup() {
      for (var i = 0, ii = this._pages.length; i < ii; i++) {
        if (this._pages[i] && this._pages[i].renderingState !== _pdf_rendering_queue.RenderingStates.FINISHED) {
          this._pages[i].reset();
        }
      }
    },

    _cancelRendering: function PDFViewer_cancelRendering() {
      for (var i = 0, ii = this._pages.length; i < ii; i++) {
        if (this._pages[i]) {
          this._pages[i].cancelRendering();
        }
      }
    },
    _ensurePdfPageLoaded: function _ensurePdfPageLoaded(pageView) {
      var _this2 = this;

      if (pageView.pdfPage) {
        return Promise.resolve(pageView.pdfPage);
      }
      var pageNumber = pageView.id;
      if (this._pagesRequests[pageNumber]) {
        return this._pagesRequests[pageNumber];
      }
      var promise = this.pdfDocument.getPage(pageNumber).then(function (pdfPage) {
        if (!pageView.pdfPage) {
          pageView.setPdfPage(pdfPage);
        }
        _this2._pagesRequests[pageNumber] = null;
        return pdfPage;
      });
      this._pagesRequests[pageNumber] = promise;
      return promise;
    },
    forceRendering: function forceRendering(currentlyVisiblePages) {
      var _this3 = this;

      var visiblePages = currentlyVisiblePages || this._getVisiblePages();
      var pageView = this.renderingQueue.getHighestPriority(visiblePages, this._pages, this.scroll.down);
      if (pageView) {
        this._ensurePdfPageLoaded(pageView).then(function () {
          _this3.renderingQueue.renderView(pageView);
        });
        return true;
      }
      return false;
    },
    getPageTextContent: function getPageTextContent(pageIndex) {
      return this.pdfDocument.getPage(pageIndex + 1).then(function (page) {
        return page.getTextContent({ normalizeWhitespace: true });
      });
    },
    createTextLayerBuilder: function createTextLayerBuilder(textLayerDiv, pageIndex, viewport) {
      var enhanceTextSelection = arguments.length > 3 && arguments[3] !== undefined ? arguments[3] : false;

      return new _text_layer_builder.TextLayerBuilder({
        textLayerDiv: textLayerDiv,
        eventBus: this.eventBus,
        pageIndex: pageIndex,
        viewport: viewport,
        findController: this.isInPresentationMode ? null : this.findController,
        enhanceTextSelection: this.isInPresentationMode ? false : enhanceTextSelection
      });
    },
    createAnnotationLayerBuilder: function createAnnotationLayerBuilder(pageDiv, pdfPage) {
      var renderInteractiveForms = arguments.length > 2 && arguments[2] !== undefined ? arguments[2] : false;

      return new _annotation_layer_builder.AnnotationLayerBuilder({
        pageDiv: pageDiv,
        pdfPage: pdfPage,
        renderInteractiveForms: renderInteractiveForms,
        linkService: this.linkService,
        downloadManager: this.downloadManager
      });
    },
    setFindController: function setFindController(findController) {
      this.findController = findController;
    },
    getPagesOverview: function getPagesOverview() {
      var pagesOverview = this._pages.map(function (pageView) {
        var viewport = pageView.pdfPage.getViewport(1);
        return {
          width: viewport.width,
          height: viewport.height,
          rotation: viewport.rotation
        };
      });
      if (!this.enablePrintAutoRotate) {
        return pagesOverview;
      }
      var isFirstPagePortrait = isPortraitOrientation(pagesOverview[0]);
      return pagesOverview.map(function (size) {
        if (isFirstPagePortrait === isPortraitOrientation(size)) {
          return size;
        }
        return {
          width: size.height,
          height: size.width,
          rotation: (size.rotation + 90) % 360
        };
      });
    }
  };
  return PDFViewer;
}();
exports.PresentationModeState = PresentationModeState;
exports.PDFViewer = PDFViewer;