pdf.js/web/pdf_outline_viewer.js

/* Copyright 2012 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.
 */

import * as pdfjsLib from 'pdfjs-web/pdfjs';

var PDFJS = pdfjsLib.PDFJS;

var DEFAULT_TITLE = '\u2013';

/**
 * @typedef {Object} PDFOutlineViewerOptions
 * @property {HTMLDivElement} container - The viewer element.
 * @property {IPDFLinkService} linkService - The navigation/linking service.
 * @property {EventBus} eventBus - The application event bus.
 */

/**
 * @typedef {Object} PDFOutlineViewerRenderParameters
 * @property {Array|null} outline - An array of outline objects.
 */

/**
 * @class
 */
var PDFOutlineViewer = (function PDFOutlineViewerClosure() {
  /**
   * @constructs PDFOutlineViewer
   * @param {PDFOutlineViewerOptions} options
   */
  function PDFOutlineViewer(options) {
    this.outline = null;
    this.lastToggleIsShow = true;
    this.container = options.container;
    this.linkService = options.linkService;
    this.eventBus = options.eventBus;
  }

  PDFOutlineViewer.prototype = {
    reset: function PDFOutlineViewer_reset() {
      this.outline = null;
      this.lastToggleIsShow = true;

      // Remove the outline from the DOM.
      this.container.textContent = '';
      // Ensure that the left (right in RTL locales) margin is always reset,
      // to prevent incorrect outline alignment if a new document is opened.
      this.container.classList.remove('outlineWithDeepNesting');
    },

    /**
     * @private
     */
    _dispatchEvent: function PDFOutlineViewer_dispatchEvent(outlineCount) {
      this.eventBus.dispatch('outlineloaded', {
        source: this,
        outlineCount: outlineCount
      });
    },

    /**
     * @private
     */
    _bindLink: function PDFOutlineViewer_bindLink(element, item) {
      if (item.url) {
        pdfjsLib.addLinkAttributes(element, {
          url: item.url,
          target: (item.newWindow ? PDFJS.LinkTarget.BLANK : undefined),
        });
        return;
      }
      var self = this, destination = item.dest;

      element.href = self.linkService.getDestinationHash(destination);
      element.onclick = function () {
        if (destination) {
          self.linkService.navigateTo(destination);
        }
        return false;
      };
    },

    /**
     * @private
     */
    _setStyles: function PDFOutlineViewer_setStyles(element, item) {
      var styleStr = '';
      if (item.bold) {
        styleStr += 'font-weight: bold;';
      }
      if (item.italic) {
        styleStr += 'font-style: italic;';
      }

      if (styleStr) {
        element.setAttribute('style', styleStr);
      }
    },

    /**
     * Prepend a button before an outline item which allows the user to toggle
     * the visibility of all outline items at that level.
     *
     * @private
     */
    _addToggleButton: function PDFOutlineViewer_addToggleButton(div) {
      var toggler = document.createElement('div');
      toggler.className = 'outlineItemToggler';
      toggler.onclick = function(event) {
        event.stopPropagation();
        toggler.classList.toggle('outlineItemsHidden');

        if (event.shiftKey) {
          var shouldShowAll = !toggler.classList.contains('outlineItemsHidden');
          this._toggleOutlineItem(div, shouldShowAll);
        }
      }.bind(this);
      div.insertBefore(toggler, div.firstChild);
    },

    /**
     * Toggle the visibility of the subtree of an outline item.
     *
     * @param {Element} root - the root of the outline (sub)tree.
     * @param {boolean} show - whether to show the outline (sub)tree. If false,
     *   the outline subtree rooted at |root| will be collapsed.
     *
     * @private
     */
    _toggleOutlineItem:
        function PDFOutlineViewer_toggleOutlineItem(root, show) {
      this.lastToggleIsShow = show;
      var togglers = root.querySelectorAll('.outlineItemToggler');
      for (var i = 0, ii = togglers.length; i < ii; ++i) {
        togglers[i].classList[show ? 'remove' : 'add']('outlineItemsHidden');
      }
    },

    /**
     * Collapse or expand all subtrees of the outline.
     */
    toggleOutlineTree: function PDFOutlineViewer_toggleOutlineTree() {
      if (!this.outline) {
        return;
      }
      this._toggleOutlineItem(this.container, !this.lastToggleIsShow);
    },

    /**
     * @param {PDFOutlineViewerRenderParameters} params
     */
    render: function PDFOutlineViewer_render(params) {
      var outline = (params && params.outline) || null;
      var outlineCount = 0;

      if (this.outline) {
        this.reset();
      }
      this.outline = outline;

      if (!outline) {
        this._dispatchEvent(outlineCount);
        return;
      }

      var fragment = document.createDocumentFragment();
      var queue = [{ parent: fragment, items: this.outline }];
      var hasAnyNesting = false;
      while (queue.length > 0) {
        var levelData = queue.shift();
        for (var i = 0, len = levelData.items.length; i < len; i++) {
          var item = levelData.items[i];

          var div = document.createElement('div');
          div.className = 'outlineItem';

          var element = document.createElement('a');
          this._bindLink(element, item);
          this._setStyles(element, item);
          element.textContent =
            pdfjsLib.removeNullCharacters(item.title) || DEFAULT_TITLE;

          div.appendChild(element);

          if (item.items.length > 0) {
            hasAnyNesting = true;
            this._addToggleButton(div);

            var itemsDiv = document.createElement('div');
            itemsDiv.className = 'outlineItems';
            div.appendChild(itemsDiv);
            queue.push({ parent: itemsDiv, items: item.items });
          }

          levelData.parent.appendChild(div);
          outlineCount++;
        }
      }
      if (hasAnyNesting) {
        this.container.classList.add('outlineWithDeepNesting');
      }

      this.container.appendChild(fragment);

      this._dispatchEvent(outlineCount);
    }
  };

  return PDFOutlineViewer;
})();

export {
  PDFOutlineViewer,
};