pdfjs-dist/lib/web/pdf_rendering_queue.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';
var CLEANUP_TIMEOUT = 30000;
var RenderingStates = {
 INITIAL: 0,
 RUNNING: 1,
 PAUSED: 2,
 FINISHED: 3
};
var PDFRenderingQueue = function PDFRenderingQueueClosure() {
 function PDFRenderingQueue() {
  this.pdfViewer = null;
  this.pdfThumbnailViewer = null;
  this.onIdle = null;
  this.highestPriorityPage = null;
  this.idleTimeout = null;
  this.printing = false;
  this.isThumbnailViewEnabled = false;
 }
 PDFRenderingQueue.prototype = {
  setViewer: function PDFRenderingQueue_setViewer(pdfViewer) {
   this.pdfViewer = pdfViewer;
  },
  setThumbnailViewer: function PDFRenderingQueue_setThumbnailViewer(pdfThumbnailViewer) {
   this.pdfThumbnailViewer = pdfThumbnailViewer;
  },
  isHighestPriority: function PDFRenderingQueue_isHighestPriority(view) {
   return this.highestPriorityPage === view.renderingId;
  },
  renderHighestPriority: function PDFRenderingQueue_renderHighestPriority(currentlyVisiblePages) {
   if (this.idleTimeout) {
    clearTimeout(this.idleTimeout);
    this.idleTimeout = null;
   }
   if (this.pdfViewer.forceRendering(currentlyVisiblePages)) {
    return;
   }
   if (this.pdfThumbnailViewer && this.isThumbnailViewEnabled) {
    if (this.pdfThumbnailViewer.forceRendering()) {
     return;
    }
   }
   if (this.printing) {
    return;
   }
   if (this.onIdle) {
    this.idleTimeout = setTimeout(this.onIdle.bind(this), CLEANUP_TIMEOUT);
   }
  },
  getHighestPriority: function PDFRenderingQueue_getHighestPriority(visible, views, scrolledDown) {
   var visibleViews = visible.views;
   var numVisible = visibleViews.length;
   if (numVisible === 0) {
    return false;
   }
   for (var i = 0; i < numVisible; ++i) {
    var view = visibleViews[i].view;
    if (!this.isViewFinished(view)) {
     return view;
    }
   }
   if (scrolledDown) {
    var nextPageIndex = visible.last.id;
    if (views[nextPageIndex] && !this.isViewFinished(views[nextPageIndex])) {
     return views[nextPageIndex];
    }
   } else {
    var previousPageIndex = visible.first.id - 2;
    if (views[previousPageIndex] && !this.isViewFinished(views[previousPageIndex])) {
     return views[previousPageIndex];
    }
   }
   return null;
  },
  isViewFinished: function PDFRenderingQueue_isViewFinished(view) {
   return view.renderingState === RenderingStates.FINISHED;
  },
  renderView: function PDFRenderingQueue_renderView(view) {
   var state = view.renderingState;
   switch (state) {
   case RenderingStates.FINISHED:
    return false;
   case RenderingStates.PAUSED:
    this.highestPriorityPage = view.renderingId;
    view.resume();
    break;
   case RenderingStates.RUNNING:
    this.highestPriorityPage = view.renderingId;
    break;
   case RenderingStates.INITIAL:
    this.highestPriorityPage = view.renderingId;
    var continueRendering = function () {
     this.renderHighestPriority();
    }.bind(this);
    view.draw().then(continueRendering, continueRendering);
    break;
   }
   return true;
  }
 };
 return PDFRenderingQueue;
}();
exports.RenderingStates = RenderingStates;
exports.PDFRenderingQueue = PDFRenderingQueue;