pdfjs-dist/lib/web/pdf_rendering_queue.js

/**
 * @licstart The following is the entire license notice for the
 * Javascript code in this page
 *
 * Copyright 2018 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.
 *
 * @licend The above is the entire license notice for the
 * Javascript code in this page
 */
"use strict";

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.PDFRenderingQueue = exports.RenderingStates = void 0;

function _classCallCheck(instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError("Cannot call a class as a function"); } }

function _defineProperties(target, props) { for (var i = 0; i < props.length; i++) { var descriptor = props[i]; descriptor.enumerable = descriptor.enumerable || false; descriptor.configurable = true; if ("value" in descriptor) descriptor.writable = true; Object.defineProperty(target, descriptor.key, descriptor); } }

function _createClass(Constructor, protoProps, staticProps) { if (protoProps) _defineProperties(Constructor.prototype, protoProps); if (staticProps) _defineProperties(Constructor, staticProps); return Constructor; }

var CLEANUP_TIMEOUT = 30000;
var RenderingStates = {
  INITIAL: 0,
  RUNNING: 1,
  PAUSED: 2,
  FINISHED: 3
};
exports.RenderingStates = RenderingStates;

var PDFRenderingQueue =
/*#__PURE__*/
function () {
  function PDFRenderingQueue() {
    _classCallCheck(this, PDFRenderingQueue);

    this.pdfViewer = null;
    this.pdfThumbnailViewer = null;
    this.onIdle = null;
    this.highestPriorityPage = null;
    this.idleTimeout = null;
    this.printing = false;
    this.isThumbnailViewEnabled = false;
  }

  _createClass(PDFRenderingQueue, [{
    key: "setViewer",
    value: function setViewer(pdfViewer) {
      this.pdfViewer = pdfViewer;
    }
  }, {
    key: "setThumbnailViewer",
    value: function setThumbnailViewer(pdfThumbnailViewer) {
      this.pdfThumbnailViewer = pdfThumbnailViewer;
    }
  }, {
    key: "isHighestPriority",
    value: function isHighestPriority(view) {
      return this.highestPriorityPage === view.renderingId;
    }
  }, {
    key: "renderHighestPriority",
    value: function 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);
      }
    }
  }, {
    key: "getHighestPriority",
    value: function 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;
    }
  }, {
    key: "isViewFinished",
    value: function isViewFinished(view) {
      return view.renderingState === RenderingStates.FINISHED;
    }
  }, {
    key: "renderView",
    value: function renderView(view) {
      var _this = this;

      switch (view.renderingState) {
        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 continueRendering() {
            _this.renderHighestPriority();
          };

          view.draw().then(continueRendering, continueRendering);
          break;
      }

      return true;
    }
  }]);

  return PDFRenderingQueue;
}();

exports.PDFRenderingQueue = PDFRenderingQueue;